Visualizing Conformance Control Mechanisms in High-Temperature Reservoirs: A Microfluidic Analysis of Pickering Emulsified Gel Systems

Visualizing Conformance Control Mechanisms in High-Temperature Reservoirs: A Microfluidic Analysis of Pickering Emulsified Gel Systems | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Visualizing Conformance Control Mechanisms in High-Temperature Reservoirs: A Microfluidic Analysis of Pickering Emulsified Gel Systems Tinku Saikia, Lucas Mejia, Abdullah Sultan, Matthew Balhoff, Jafar Al Hamad This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3975156/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 12 Oct, 2024 Read the published version in Microfluidics and Nanofluidics → Version 1 posted 16 You are reading this latest preprint version Abstract In the context of mature oil fields, the management of conformance control and water shut-off stands out as a formidable challenge. Our prior research endeavors (Saikia et al., 2021, 2020) have introduced an innovative Pickering emulsified gel system tailored for the precise adjustment of relative permeability in high-temperature reservoirs. To optimize the efficiency of this system, a comprehensive comprehension of the underlying conformance control mechanism is deemed imperative. Traditionally, the exploration of conformance control mechanisms leans on empirical data culled from core flooding experiments, computerized tomography (CT) scans, nuclear magnetic resonance spectroscopy (NMR), and analogous methodologies. Nevertheless, these conventional avenues often fall short in delivering real-time visual analyses, thereby raising doubts about their reliability in predicting conformance mechanisms. In our research study, we have harnessed the capabilities of microfluidics to unlock real-time visual insights into the mechanisms governing conformance control. Employing two distinct glass micromodel geometries, we have conducted Pickering emulsified gel treatments at a scorching 105°C to achieve the targeted conformance control within these micromodels. By synergizing image and video analysis with injection pressure measurements, our findings have cast doubt on the previously posited Thin Film conformance control mechanism, revealing a more nuanced perspective on this intricate process. Conformance Control Water shut-off Emulsified Gel Microfluidic. Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 1. Introduction The comprehensive study of multiphase flow in porous media holds paramount significance across various industries, with particular prominence in the oil and gas sector. Reservoirs, inherently porous in nature, serve as reservoirs for hydrocarbons, where the multiphase flow of oil, gas, and water plays a pivotal role (Alhammadi et al., 2017). Understanding the intricate dynamics of multiphase flow in porous media is critical for the successful implementation of enhanced oil recovery techniques, conformance control strategies, waterflooding processes, and more (Auset and Keller, 2004; Gupta et al., 2011; Sohrabi et al., 2015; Tanzil et al., 2002; Tavassoli et al., 2016) (Asadi-Saghandi et al., 2022). Excessive water production from oil wells poses a substantial challenge, particularly in mature wells (Saikia et al., 2019). Water shut-off operations, originally devised to mitigate excessive water production, have been adapted to address conformance issues by ameliorating reservoir heterogeneity (Divandari et al., 2021; Goudarzi et al., 2015). In the realm of water shut-off and conformance control, chemical treatment methods have taken center stage. These methods employ a repertoire of agents, including in-situ gels, polymers, water swelling polymers, micro matrix cement, and HWSO plugging agents, to curtail water production and enhance conformance in oil wells (Dai et al., 2011) (Alain Zaitoun et al., 2007) (Bai et al., 2008) (Peirce et al., 2014) (Liu et al., 2010) (SUN and BAI, 2017) (Yin et al., 2022). Core flooding experiments, a conventional technique, are commonly employed to investigate multiphase flow in realistic porous materials (Cuthiell et al., 1993; Qi et al., 2017). These experiments yield macro-scale data, including pressure variations, fluid saturation profiles, and produced fluid properties, offering insights into multiphase flow behavior within porous rocks. However, the complex 3D geometry of core sections presents challenges for direct visualization of micron-scale multiphase flow. To address this limitation, advanced techniques such as medical CT scans and NMR spectroscopy have been employed to complement core flooding experimental results (Cuthiell et al., 1993) (Siavashi et al., 2022). Nevertheless, these techniques do not provide dynamic, high-resolution micron-scale visualization of multiphase flow within core sections during experiments (Xu et al., 2017). Conversely, chemical water shut-off and conformance control agents, including those previously mentioned, have primarily been tested in core flooding setups, often supported by medical CT scans, NMR spectroscopy, and simulation studies. Researchers have proposed various conformance mechanisms based on their findings. Some posit that polymer microgels selectively invade high-permeability layers while avoiding low-permeability layers due to their low viscosity and steric effects (Cozic et al., 2009) (Seright et al., 2012). Others suggest that microgels show minimal penetration in low-permeability layers owing to their large size (A. Zaitoun et al., 2007). Divergent conformance mechanisms have also been proposed, such as the Disproportionate Permeability Reduction (DPR) or Relative Permeability Modification (RPM) effect, which involves microgels compressing under water-oil capillary pressure, selectively reducing water permeability (Chauveteau et al., 2004) (Rousseau et al., 2005). Additionally, the mechanism of microscopic diversion suggests that rigid polymer microgel colloids promote the recovery of capillary-trapped residual oil through pore-blocking-induced redistribution of flow (Spildo et al., 2009). Similar proposals exist for other conformance control chemical treatment methods, all originating from experimental results obtained via core flooding experiments, pressure variations, permeability reduction, residual oil saturation, effluent profiles, and more (Cozic et al., 2009) (A. Zaitoun et al., 2007). These disputes regarding conformance control mechanisms can be resolved through the application of microfluidic analysis, which allows for the efficient study and visualization of micron-scale multiphase flow. Glass micromodels, designed to emulate the pore structures of subsurface rocks, provide a promising avenue for such investigations. In our previous work, we developed an invert Pickering emulsified gel system designed for high-temperature reservoirs. This system, tested as a conformance control mechanism, demonstrated the ability to curtail water production while preserving oil flow (Saikia et al., 2021, 2020; Saikia and Sultan, 2020). Utilizing core flooding experiments and microcomputed tomography (CT) imaging, we postulated the "Thin Film conformance control mechanism" based on experimental data. The current research endeavors employ microfluidic glass micromodels to delve into the intricacies of conformance control mechanisms. Our objective is to gain a profound understanding of these mechanisms and validate the hypothesized "Thin Film conformance mechanism." To the best of our knowledge, this represents the pioneering study to utilize glass micromodels for elucidating conformance control mechanisms. 2. Experimental Section 2.1 Materials The emulsion system developed and used as a conformance control system was an invert Pickering emulsion. The continuous phase is the oleic phase (diesel oil), and the dispersed phase is the aqueous phase (gelant). The diesel oil was purchased from the local gas station. The density and viscosity of the diesel oil was 0.832kg/L and 1.6cP respectively. The crude oil used in this work was Arabian heavy crude oil with a density of 890 kg/m 3 and 170 Cp of zero shear viscosity at 25℃ (Figure S1 ). The gelant or aqueous phase is a mixture of polyacrylamide (PAM) and polyethylenimine (PEI). The PAM was purchased from SNF Floerger, France and PEI from MPI Biomedicals. The PAM is used in powdered form having a molecular weight of 4.5-7.5 MDa. The PEI solution was 50% aqueous solution with a molecular weight and density of 43 kDa and 1.07 g/mL respectively. The PEI is used as a crosslinker for gelation in the emulsion system. The desired emulsion stability was obtained with the help of Cloisite 20, which is an organically modified phyllosilicate. The Cloisite 20 is used as an emulsifier in the emulsion system and obtained from BYK, U.K. The Cloisite 20 have a particle size of D50 < 10 µm and a density of 1.80 g/cm 3 (at 20 ℃). The PAM and PEI solution was prepared using field mixing water obtained from a local operating company. The TDS in the field mixing water was maintained at 976.2 with the composition shown in Table S1. 2.2 Proposed (postulate) Thin Film Conformance Control Mechanism (during core flooding experiments) The proposed "Thin Film" conformance control mechanism is depicted comprehensively in Figure 1 . The process commences with the injection of an invert Pickering emulsion into the reservoir region characterized by high water cut, as illustrated in Figure 1A . The formulation of this invert emulsion system is engineered to facilitate its breakdown into distinct oleic and aqueous phases, driven by the elevated temperature of 105°C. This temperature regime closely emulates the conditions prevailing in high-temperature oil wells. Upon breakdown, the separated aqueous phase undergoes a phase transition into a gel-like state at higher temperatures, effectively occupying the central void spaces within the pore channels. Concurrently, the isolated oil phase envelops the gel phase, resulting in the formation of a thin, oil-rich layer encompassing the gel, as exemplified in Figure 1B . Subsequently, during the post-treatment backflow phase, the crude oil readily traverses the Thin Film segment due to its favorable miscibility with diesel oil. In contrast, the formation brine exhibits non-miscibility with diesel oil within the Thin Film. Consequently, the brine is compelled to displace the entire diesel oil residing within the Thin Film to facilitate its own flow, as depicted in Figure 1C . Notably, within the context of multiphase flow, fluids with lower resistance inherently take precedence. Thus, this emulsified gel treatment strategy orchestrates a dynamic that aligns with the principle of least resistance, ultimately delivering the targeted conformance control and effecting the desired relative permeability modification. 2.3 Microfluidic Glass Micromodel In this research endeavor, two distinct glass micromodels were meticulously employed for experimentation, as illustrated in Figure 2 . The initial glass micromodel, referred to as "micromodel I," embodies a homogeneous structure characterized by a circular grain geometry with a diameter of 136 µm, effectively emulating the rock structure within the micromodel ( Figure 2A & 2B ). The inter-grain spacing, set at 63 µm, faithfully replicates pore throat dimensions. The entirety of the circular grain configuration spans 14mm in length and 7.27 mm in width. Maintaining a pore channel depth of 0.011mm, this model exhibits a porosity of 65% and houses a total pore volume of 0.72 µL. Conversely, the second glass micromodel, denominated as "micromodel-II," introduces a heterogeneous paradigm that mirrors a more realistic rock matrix pattern interspersed with high-permeability fractures, as vividly depicted in Figure 2C & 2D . This glass micromodel extends over dimensions of 4.415 mm in length and 3.302 mm in width, with both fractures and pore spaces sharing a common depth of 0.011 mm. The fractures themselves boast a width of 100 µm. Micromodel II exhibits a porosity of 52% and possesses a pore volume measuring 0.08 µL. To bring these glass micromodels to fruition, we leveraged high-resolution photolithographic masks provided by CAD Art Services, USA. The fabrication process followed established photolithography procedures, complemented by hydrofluoric acid etching techniques (Xu et al., 2017). Furthermore, a chloro-dimethyloctylsilane coating was applied, rendering glass micromodel I water-wet, while glass micromodel II adopted an oil-wet nature (Mejia et al., 2019). 2.4 Microfluidic Experimental setup The experimental procedures were meticulously executed within a meticulously self-assembled microfluidic setup. Fluid infusion was adeptly facilitated by a Harvard Apparatus PhD 2000 syringe pump. To capture intricate details of the glass micromodels in real-time, we harnessed the capabilities of the Meros high-speed digital microscope. This advanced microscope is outfitted with high-power LED coaxial illumination, boasting an impressive frame rate of approximately 4100 frames per second (fps). Seamless integration with computer systems enabled streamlined data acquisition and analysis. For the fluidic connections between the system components, we employed 1/16-inch OD tubing crafted from PFA (perfluoroalkoxy). This choice of material ensures compatibility with the glass micromodels while maintaining the integrity of the experimental setup. In the context of pressure monitoring, the uProcess pressure sensors emerged as indispensable tools. These sensors possess a commendable pressure measurement range spanning from 0 to 250 Kpa, and they were strategically deployed to measure pressure levels within the inlet line feeding into the glass micromodel. Collectively, this ensemble of specialized equipment and instrumentation facilitated the precise execution and data acquisition of our microfluidic experiments. 2.5 Experimental procedure In this research undertaking, the glass micromodels underwent a meticulous pre-treatment process to emulate the conditions prevailing in reservoir zones with high water production issues. Initially, full saturation of the glass micromodels was achieved using field mixing water, closely mirroring the reservoir conditions. The introduction of field mixing water into the glass micromodels was expertly executed via a gas-tight syringe, specifically the Hamilton 250µL Model 1725 TLL SYR, operating at a controlled flow rate of 50µL/hr. Towards the latter stages of the field mixing water (brine) injection, the flow rate was elevated to 100 µL/hr to dislodge any residual air bubbles trapped within the glass micromodel. Following the successful saturation of the glass micromodels with field mixing water, the specially developed Pickering emulsified gel system was introduced into the system at a consistent flow rate of 50 µL/hr. The formulation and emulsification process of this Pickering emulsified gel system have been extensively detailed in Saikia et al., 2019. Approximately 2 pore volumes of the Pickering emulsified gel system were meticulously injected into the glass micromodels. Post-emulsion injection, the glass micromodels were subjected to a controlled temperature of 105℃, skillfully maintained using a hot plate. This temperature exposure spanned a duration of 24 hours. The inherent design of the Pickering emulsified gel system ensured that, during this period, the emulsion would undergo phase separation, resulting in the formation of distinct aqueous and oleic phases (Saikia et al., 2021, 2019). The aqueous phase subsequently underwent a transformation into a rigid gel structure, serving as a formidable impediment to the flow of the formation water. Upon successful gelation, diesel or crude oil was introduced into the glass micromodels at carefully regulated flow rates of 50 µL/hr and 100 µL/hr. The ensuing experiments meticulously monitored and scrutinized the flow behavior and pressure variations during both the diesel/crude oil injection and the subsequent introduction of field mixing water (brine). This comparative analysis shed light on the contrasting dynamics between the two fluid injections, providing valuable insights into the conformance control mechanisms at play. 3. Results and Discussion 3.1 Conformance Control Mechanism in Glass Micromodel I In this research study, the physical state of the emulsion system before its injection into the glass micromodel is depicted in Figure 4(A) . The emulsion comprises an aqueous phase (PAM+PEI) dispersed within a continuous oleic phase. Notably, the emulsion droplets exhibit non-uniform spherical characteristics. The hypothesized conformance control mechanism ( Figure 1 ) posited that these emulsion droplets would enter the pore channels in their droplet form. However, during the actual injection into the glass micromodel ( Figure 4B & 4C ), an unexpected phenomenon transpired. The emulsion droplets began coalescing prior to reaching the pore matrix section within the glass micromodel. This premature coalescence can be attributed to the substantial shear stress encountered during the injection process. Consequently, the emulsion droplets transformed into a dispersed aqueous slug (comprising the major portion) and dispersed aqueous drops (constituting the minor portion) within the glass micromodel. Additionally, it was observed that minimal coalescence of the aqueous slug or droplets occurred during the subsequent 24-hour shut-in period at the elevated temperature of 105℃. In Figure 4(C) , a distinct gelled aqueous phase, manifesting as slugs and drops, effectively obstructed the pore space within the glass micromodel matrix. Meanwhile, the separated oleic phase occupied the remaining matrix space, potentially providing a pathway for oil flow. Following the successful gelation of the aqueous phase, crude oil was introduced into the glass micromodel to elucidate the flow path. Contrary to the anticipated behavior posited in the hypothesized mechanism ( Figure 1B ), the observed oil flow in the glass micromodel exhibited an unexpected pattern. Notably, the postulated Thin Film structure was conspicuously absent following gelation (shut-in period), and the oil primarily flowed through two discernible macroscopic channels, as depicted in Figure 5 . This outcome diverged significantly from the anticipated "Thin Film mechanism." Subsequent experiments involving the injection of both crude oil and diesel oil aimed to ascertain whether altering the type of oleic phase would impact miscibility or flow patterns. It was observed that crude oil and diesel oil exhibited a high degree of miscibility, facilitating smooth flow through the designated oil channels. This observation was further corroborated by the accompanying video evidence ( Video 1 ). To further probe the conformance control mechanism of the emulsified gel system, field mixing water (brine) was introduced into the glass micromodel ( Figure 6 ). It became evident that the injected brine struggled to identify alternative flow paths within the glass micromodel other than the oil channel. Consequently, the brine flowed through the oil channel, displacing the oil towards the outlet, as depicted in Figure 6(A) with black arrows indicating the brine flow path. Even after water breakthrough, the brine encountered resistance compared to the relatively unhindered oil flow. The brine became entrapped within the pore matrix, while the oil continued to flow with minimal resistance through the available space between the blocked brine and matrix grains ( Figure 6B ). A similar trend was observed in Figure 6C, 6D, and 6E , where during brine injection, the diesel oil was displaced from the glass micromodel, resulting in continuous flow with minimal resistance. However, once water breakthrough occurred, the flow pattern abruptly changed, with intermittent brine flow through the same channel indicating increased resistance encountered by the brine after treatment with the Pickering emulsified gel. These flow patterns are further elucidated in Videos 2 and 3 . Consistent findings were also reflected in the pressure measurement data, as presented in Figure 7A & 7B . During diesel oil injection post-gelation, the injection commenced at a flow rate of 50 µL/hr, with an initial pressure of approximately 32 Kpa ( Figure 7A ). After about 5 minutes, the pressure stabilized at approximately 150 Kpa, prompting an increase in the injection flow rate to 100 µL/hr. This change led to a subsequent increase in pressure to approximately 190 Kpa within the following 3 minutes. Subsequently, the pressure remained constant at 190 Kpa for an additional 18 minutes. Similarly, during field mixing water (brine) injection into the micromodel at a flow rate of 50 µL/hr, a steep increase in pressure reading was observed, escalating from 51 Kpa to 250 Kpa ( Figure 7B ). The injection flow rate was maintained at 50 µL/hr for 10 minutes, during which the pressure reading remained constant at 250 Kpa. This value persisted even after the brine breakthrough. While the pressure reading may have surpassed this value, the pressure sensors' upper limit capped it at 250 Kpa. Subsequently, the injection flow rate was increased to 100 µL/hr for an additional 15 minutes, with no noticeable variation in pressure readings. Comparing both pressure profiles during oil and brine injection, it is evident that brine encountered significant resistance during its flow. Notably, the maximum injection pressure recorded during oil injection was 190 Kpa, while it reached 250 Kpa during brine injection. This resistance to flow can be attributed to the gel treatment's role as a relative permeability modifier. 3.2 Conformance Control Mechanism in Glass Micromodel II In the case of glass micromodel II, the initial step involved saturating it with field mixing water, as illustrated in Figure 8A . During the subsequent injection of Pickering emulsified gel, a distinctive behavior was observed. Within glass micromodel II, the emulsion system entered the matrix primarily in the form of substantial aqueous phase slugs accompanied by small quantities of aqueous phase drops dispersed within a continuous oil phase ( Figure 8B ). This phenomenon is visually demonstrated in the attached video 4 . Following the emulsion injection, the glass micromodel was subjected to a temperature of 105℃, placed atop a hot plate, for 24 hours. During this period, the aqueous phase underwent a transition into a gel phase, occupying a significant portion of the pore space within the matrix, while the remaining space was filled by the separated oleic phase ( Figure 8C ). Subsequent injection of crude oil into glass micromodel II revealed a unique flow pattern. Contrary to the anticipated Thin Film mechanism, the injected crude oil predominantly flowed through a single fracture, resembling a channel flow. Most of the matrix space remained blocked by the rigid gel, except for the specified fracture. Figure 9A illustrates the initial state of the glass micromodel during crude oil injection, while Figure 9B represents the state at the conclusion of the crude oil injection. Remarkably, minimal deviation in the crude oil flow path occurred throughout the entire injection process. A macroscopic view of glass micromodel II after the experiment is presented in Figure 9(C) . Notably, the injected crude oil primarily followed a solitary flow path through the fracture. A notable observation was the change in crude oil color during the injection, shifting from lighter shades at the beginning to darker tones towards the end. This color alteration was attributed to the fact that the flow channel had initially been occupied by diesel oil, a component separated from the emulsion system. Consequently, the injected crude oil exhibited miscibility with the diesel oil, enabling a continuous flow through the channel, as evident in video 5 . Following the conclusion of the crude oil injection stage, field mixing water (brine) was introduced into glass micromodel II. During brine injection, behavior analogous to that observed in glass micromodel I was evident. The injected brine struggled to identify alternative pathways within the micromodel, primarily following the crude oil flow path. This brine flow path is indicated by white arrows in Figure 10 . While the brine displaced the crude oil from the oil channel, it failed to entirely displace it. The brine exhibited intermittent flow within the channel, as seen in video 6 . This intermittent behavior could be attributed to the oil-wet wettability of glass micromodel II. Consequently, in glass micromodel II, the brine intermittently encountered flow resistance compared to the continuous crude oil flow. Even after the brine breakthrough, the crude oil continued to flow continuously. Moreover, the brine exerted pressure, compelling the crude oil out of the flow channels. Figure 10 visually depicts this behavior, with yellow arrows indicating the crude oil's displacement to previously unoccupied areas of the glass micromodel. Pressure profiles during both crude oil and brine injection within glass micromodel II are illustrated in Figure 11 . During the initial crude oil injection phase, maintained at a flow rate of 50 µL/hr, the pressure reading increased from 30 Kpa to 93 Kpa within 3 minutes. Subsequently, the pressure stabilized at 93 Kpa ( Figure 11A ). Upon increasing the injection flow rate to 100 µL/hr, the pressure rapidly rose from 93 Kpa to 155 Kpa within 3 minutes. Despite maintaining the flow rate at 100 µL/hr for an additional 18 minutes, the pressure remained constant at 155 Kpa. In contrast, during the transition to brine injection, maintained at 50 µL/hr, the pressure exhibited a steeper ascent, surging from 51 Kpa to 250 Kpa ( Figure 11B ). This pressure rise transpired within 18 minutes of brine injection. Subsequently increasing the flow rate to 100 µL/hr failed to elicit any noticeable change in pressure readings, with the pressure consistently maintained at the peak value of 250 Kpa. The discernible difference in peak injection pressures between crude oil and brine injection at equivalent flow rates underscores the resistance encountered by the brine during its flow through glass micromodel II relative to the crude oil. Brine injection persisted for approximately 60 minutes, yet the pressure reading remained capped at 250 Kpa, reflecting the pressure sensors' upper limit. Additionally, video 6 confirmed the intermittent flow of brine within the channel, highlighting the reduced relative permeability of brine following gel treatment. In contrast, oil relative permeability remained unaffected. The findings align with those observed during core flooding experiments conducted using the same Pickering emulsified gel system (Saikia et al., 2021) (Saikia et al., 2019), suggesting that the originally postulated conformance control mechanism only partially holds. While the hypothesis of emulsion separation and aqueous phase gelling was confirmed, the Thin Film mechanism was debunked. Instead, the newly proposed conformance control mechanism involving Relative Permeability Modified Channel Flow, as observed in the experiments, and discussed in the results, presents a more accurate representation. Under this mechanism, following gel treatment, crude oil flows continuously through the diesel oil channel, whereas brine flow remains intermittent. 4. Conclusion This research endeavor has yielded several valuable insights into the conformance control mechanism employing an invert Pickering emulsion, as investigated through two distinct glass micromodels. The following conclusions can be deduced from this comprehensive study: In contrast to the initially hypothesized Thin Film mechanism, it was observed that the emulsified gel system predominantly infiltrates the matrix space in the form of emulsion slugs. Coalescence of emulsion droplets occurred during the injection process, resulting in the gelling of the aqueous phase within the micromodel's matrix space, particularly under elevated temperature conditions. This behavior contradicts the formation of clearly distinguishable aqueous gel phases within the central pore space and surrounding oleic Thin Films, as envisaged in the Thin Film mechanism. Crude oil exhibited a distinctive flow pattern, traversing specific flow channels created by the separated emulsion oleic phase, facilitated by their miscibility. This flow behavior deviates from the anticipated Thin Film flow. During brine injection, the injected brine struggled to locate alternative flow channels, instead being confined to the crude oil flow channel. Consequently, brine flow exerted pressure on the oil within the channel, propelling it towards the outlet or the remaining matrix space in the micromodel, owing to the immiscibility of the two phases. The flow of injected brine within the flow channel remained intermittent even after achieving brine breakthrough within the micromodels. Importantly, brine encountered notable flow resistance within the flow channels, resulting in higher injection pressure readings during brine flow at equivalent injection flow rates compared to crude oil flow. Taken together, these observations conclusively demonstrate that the originally postulated Thin Film conformance control mechanism is only partially accurate. This microfluidic investigation has provided valuable insights into the authentic conformance mechanism governing conformance control and water shut-off treatments. Declarations Acknowledgment The authors would like to acknowledge King Fahd University of Petroleum & Minerals for providing necessary laboratory facilities. Author Information Dr. Tinku Saikia*(Corresponding Author) Email- [email protected] Dr. Abdullah Sultan Email - [email protected] Dr. Matthew Balhoff Email - [email protected] Dr. Lucas Mejia Email - [email protected] Mr. Jafar Sadeq Al Hamad Email: [email protected] Funding Information None References Alhammadi, A.M., Alratrout, A., Singh, K., Bijeljic, B., Blunt, M.J., 2017. In situ characterization of mixed-wettability in a reservoir rock at subsurface conditions. Sci. Reports 2017 71 7, 1–9. https://doi.org/10.1038/s41598-017-10992-w Asadi-Saghandi, H., Karimi-Sabet, J., Ghorbanian, S., Moosavian, S.M.A., 2022. 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A Thorough Investigation of Mechanisms of Enhanced Oil Recovery by Carbonated Water Injection. Proc. - SPE Annu. Tech. Conf. Exhib. 2015-January, 6497–6529. https://doi.org/10.2118/175159-MS Spildo, K., Skauge, A., Aarra, M.G., Tweheyo, M.T., 2009. A new polymer application for North Sea reservoirs. SPE Reserv. Eval. Eng. https://doi.org/10.2118/113460-PA SUN, X., BAI, B., 2017. Comprehensive review of water shutoff methods for horizontal wells. Pet. Explor. Dev. https://doi.org/10.1016/S1876-3804(17)30115-5 Tanzil, D., Hirasaki, G.J., Miller, C.A., 2002. Mobility of Foam in Heterogeneous Media: Flow Parallel and Perpendicular to Stratification. SPE J. 7, 203–212. https://doi.org/10.2118/78601-PA Tavassoli, S., Korrani, A.K.N., Pope, G.A., Sepehrnoori, K., 2016. Low-Salinity Surfactant Flooding—A Multimechanistic Enhanced-Oil-Recovery Method. SPE J. 21, 0744–0760. https://doi.org/10.2118/173801-PA Xu, K., Liang, T., Zhu, P., Qi, P., Lu, J., Huh, C., Balhoff, M., 2017. A 2.5-D glass micromodel for investigation of multi-phase flow in porous media. Lab Chip. https://doi.org/10.1039/c6lc01476c Yin, H., Yin, X., Cao, R., Zeng, P., Wang, J., Wu, D., Luo, X., Zhu, Y., Zheng, Z., Feng, Y., 2022. In situ crosslinked weak gels with ultralong and tunable gelation times for improving oil recovery. Chem. Eng. J. https://doi.org/10.1016/j.cej.2021.134350 Zaitoun, Alain, Kohler, N., Montemurro, M.A., 2007. Control of Water Influx in Heavy-Oil Horizontal Wells by Polymer Treatment. https://doi.org/10.2523/24661-ms Zaitoun, A., Tabary, R., Rousseau, D., Pichery, T., Nouyoux, S., Mallo, P., Braun, O., 2007. Using microgels to shut off water in a gas storage well, in: Proceedings - SPE International Symposium on Oilfield Chemistry. https://doi.org/10.2118/106042-ms Videos Videos 1 to 6 are not available with this version. Additional Declarations No competing interests reported. Supplementary Files SupplementaryMaterial.docx Cite Share Download PDF Status: Published Journal Publication published 12 Oct, 2024 Read the published version in Microfluidics and Nanofluidics → Version 1 posted Editorial decision: Revision requested 16 Sep, 2024 Reviews received at journal 15 Sep, 2024 Reviews received at journal 10 Sep, 2024 Reviews received at journal 31 Aug, 2024 Reviewers agreed at journal 28 Aug, 2024 Reviewers agreed at journal 26 Aug, 2024 Reviewers agreed at journal 26 Aug, 2024 Reviewers agreed at journal 25 Jul, 2024 Reviews received at journal 08 May, 2024 Reviewers agreed at journal 03 May, 2024 Reviewers agreed at journal 25 Apr, 2024 Reviewers agreed at journal 17 Apr, 2024 Reviewers invited by journal 02 Mar, 2024 Editor assigned by journal 25 Feb, 2024 Submission checks completed at journal 23 Feb, 2024 First submitted to journal 21 Feb, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3975156","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":274869221,"identity":"08dd9503-a5bc-4941-a331-a25ead59270b","order_by":0,"name":"Tinku Saikia","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4UlEQVRIie2PPQrCQBBGJwxsmklsN0Q9g7KQ0hwmrV0qsVAQtPQEHsJmL7BFGsFWsPEHrGxSKAop3GijTTZ2gvsGhq+YB98AWCy/COrREEdwdmXwTQa9KdgpAzMq8FKAAzBeBqMSu54SVPSawQxPg0u/12SA+8OmspifJN40oRBZtG3JRBdjQvQrFRLKGyO1EaJtIFErxEKjQsVIK+41DeSonqLLKF2MIieXqoaiSHQX04yCCaWhIzNiaPjFna8EPxfDmK+zZX6Xw7jhTvbHKuUDpOeue17i3L65tlgslr/hAW9iNHxGA/3JAAAAAElFTkSuQmCC","orcid":"","institution":"King Fahd University of Petroleum \u0026 Minerals","correspondingAuthor":true,"prefix":"","firstName":"Tinku","middleName":"","lastName":"Saikia","suffix":""},{"id":274869222,"identity":"1999d37a-4656-47a0-8758-5dbe6d46bf25","order_by":1,"name":"Lucas Mejia","email":"","orcid":"","institution":"The University of Texas at Austin","correspondingAuthor":false,"prefix":"","firstName":"Lucas","middleName":"","lastName":"Mejia","suffix":""},{"id":274869223,"identity":"3e0c70c8-c74e-44a9-839a-f96aa4852b0e","order_by":2,"name":"Abdullah Sultan","email":"","orcid":"","institution":"King Fahd University of Petroleum \u0026 Minerals","correspondingAuthor":false,"prefix":"","firstName":"Abdullah","middleName":"","lastName":"Sultan","suffix":""},{"id":274869224,"identity":"bcce1063-c97d-48e4-b8c0-009ef411845e","order_by":3,"name":"Matthew Balhoff","email":"","orcid":"","institution":"The University of Texas at Austin","correspondingAuthor":false,"prefix":"","firstName":"Matthew","middleName":"","lastName":"Balhoff","suffix":""},{"id":274869225,"identity":"37962a98-47ba-4d65-881c-81088ff11e57","order_by":4,"name":"Jafar Al Hamad","email":"","orcid":"","institution":"King Fahd University of Petroleum \u0026 Minerals","correspondingAuthor":false,"prefix":"","firstName":"Jafar","middleName":"Al","lastName":"Hamad","suffix":""}],"badges":[],"createdAt":"2024-02-21 10:01:48","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3975156/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3975156/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10404-024-02770-8","type":"published","date":"2024-10-12T15:57:54+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":52043838,"identity":"87bc7df6-42f0-40c8-8a93-b5dc85dba6bf","added_by":"auto","created_at":"2024-03-05 19:03:39","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":246377,"visible":true,"origin":"","legend":"\u003cp\u003ePostulated (Thin Film) Conformance Control Mechanism derived from conventional core flooding experimental results \u003cstrong\u003e(A)\u003c/strong\u003e Pickering Emulsion Injection \u003cstrong\u003e(B)\u003c/strong\u003eEmulsion Separation and Gelation \u003cstrong\u003e(C)\u003c/strong\u003eFormation water and Crude oil Flow\u003c/p\u003e","description":"","filename":"image1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-3975156/v1/5bf0ff8d19245e35e8a02cfa.jpeg"},{"id":52044369,"identity":"ff8dd5bd-5261-4a89-9467-54f2eda8b233","added_by":"auto","created_at":"2024-03-05 19:11:39","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":442725,"visible":true,"origin":"","legend":"\u003cp\u003eGlass micromodels. \u003cstrong\u003e(A) \u0026amp; (B)\u003c/strong\u003e-Micromodel I; \u003cstrong\u003e(C) \u0026amp; (D)\u003c/strong\u003e- Micromodel II\u003c/p\u003e","description":"","filename":"image2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-3975156/v1/be1424c3beb9c1b96c41f155.jpeg"},{"id":52043848,"identity":"b255166b-7a2b-4309-993f-3960fd7a2be4","added_by":"auto","created_at":"2024-03-05 19:03:39","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":121294,"visible":true,"origin":"","legend":"\u003cp\u003eMicrofluidic Experimental Setup\u003c/p\u003e","description":"","filename":"image3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-3975156/v1/1d9c73edb042d487ff4fe29e.jpeg"},{"id":52043839,"identity":"4430a526-9c33-4f3f-809d-d0f1de0623e5","added_by":"auto","created_at":"2024-03-05 19:03:39","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":435754,"visible":true,"origin":"","legend":"\u003cp\u003eEmulsion injection and gelation in glass micromodel I. \u003cstrong\u003e(A)\u003c/strong\u003e Microscopic image of the emulsion system before injection \u003cstrong\u003e(B)\u003c/strong\u003e Emulsion system after the injection into the glass micromodel \u003cstrong\u003e(C)\u003c/strong\u003e Gelation in the glass micromodel after heating at 105℃ for 24 hours.\u003c/p\u003e","description":"","filename":"image4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-3975156/v1/84e0fda99ce5be654e7ef3ec.jpeg"},{"id":52043841,"identity":"195fa5fc-e506-499c-9eeb-36e0ad0fce94","added_by":"auto","created_at":"2024-03-05 19:03:39","extension":"jpeg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":291778,"visible":true,"origin":"","legend":"\u003cp\u003eOil Injection after gelation in glass Micromodel-I. \u003cstrong\u003e(A)\u003c/strong\u003e Oil Flow Channel 1 \u003cstrong\u003e(B)\u003c/strong\u003eOil Flow Channel 2 \u003cstrong\u003e(C)\u003c/strong\u003e Macroscopic image of oil flow channels in the glass micromodel I\u003c/p\u003e","description":"","filename":"image5.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-3975156/v1/8442c72e53a1b1dd4854b902.jpeg"},{"id":52043850,"identity":"32d6c0c8-aaf0-453d-b9da-9ec6f70f0812","added_by":"auto","created_at":"2024-03-05 19:03:40","extension":"jpeg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":430933,"visible":true,"origin":"","legend":"\u003cp\u003eBrine Injection after gelation in glass Micromodel-I. \u003cstrong\u003e(A)\u003c/strong\u003e Brine flowing through oil channel (pore matrix) and displacing oil towards outlet \u003cstrong\u003e(B)\u003c/strong\u003e Zoomed image (pore matrix) of brine flow during brine injection \u003cstrong\u003e(C)\u003c/strong\u003e Diesel was pushed in the oil channel during brine injection \u003cstrong\u003e(D)\u003c/strong\u003e Brine reaching the outlet of the glass micromodel \u003cstrong\u003e(E)\u003c/strong\u003e Brine breakthrough and change in flow pattern\u003c/p\u003e","description":"","filename":"image6.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-3975156/v1/933d8715a0386d1b23cb414c.jpeg"},{"id":52043846,"identity":"87db2bb8-334f-46a9-8649-9c610d176051","added_by":"auto","created_at":"2024-03-05 19:03:39","extension":"jpeg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":117584,"visible":true,"origin":"","legend":"\u003cp\u003eInjection Pressure in Glass Micromodel I \u003cstrong\u003e(A)\u003c/strong\u003e During crude oil injection after gelation \u003cstrong\u003e(B)\u003c/strong\u003e During brine injection after gelation\u003c/p\u003e","description":"","filename":"image7.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-3975156/v1/9f53ca8d7395ce695545894b.jpeg"},{"id":52043845,"identity":"93871ecc-158e-4a63-814c-c6998d329224","added_by":"auto","created_at":"2024-03-05 19:03:39","extension":"jpeg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":519118,"visible":true,"origin":"","legend":"\u003cp\u003eEmulsion Injection and gelation in glass micromodel II. \u003cstrong\u003e(A)\u003c/strong\u003e Glass micromodel II saturated with field mixing water \u003cstrong\u003e(B)\u003c/strong\u003e Glass micromodel II saturated with emulsified gel system \u003cstrong\u003e(C)\u003c/strong\u003e Glass micromodel after gelation at 105℃ for 24 hours\u003c/p\u003e","description":"","filename":"image8.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-3975156/v1/d9f5287ba21a9a19a79e2565.jpeg"},{"id":52043847,"identity":"98c15f20-b989-4d64-ab0d-6a2e61ed9817","added_by":"auto","created_at":"2024-03-05 19:03:39","extension":"jpeg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":472829,"visible":true,"origin":"","legend":"\u003cp\u003eOil Injection after gelation in glass Micromodel-II. \u003cstrong\u003e(A)\u003c/strong\u003e Oil Flow Channel during the initial oil injection \u003cstrong\u003e(B)\u003c/strong\u003e Oil Flow Channel during the end of oil injection \u003cstrong\u003e(C)\u003c/strong\u003e Macroscopic image of oil flow channel in the glass micromodel-II\u003c/p\u003e","description":"","filename":"image9.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-3975156/v1/422e508c81c0f6ef740aaf4f.jpeg"},{"id":52043849,"identity":"812f47c5-173a-4e0b-b84b-ec40460f1a86","added_by":"auto","created_at":"2024-03-05 19:03:40","extension":"jpeg","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":511322,"visible":true,"origin":"","legend":"\u003cp\u003eBrine Injection after gelation in glass Micromodel II. \u003cstrong\u003e(A)\u003c/strong\u003e Glass Micromodel during initiation of brine injection \u003cstrong\u003e(B)\u003c/strong\u003e Glass Micromodel during intermediate time of brine injection \u003cstrong\u003e(C)\u003c/strong\u003e Glass Micromodel at the end of brine injection\u003c/p\u003e","description":"","filename":"image10.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-3975156/v1/b3b956b91ef5840210f724c6.jpeg"},{"id":52043843,"identity":"6d480203-51f7-4bff-a29a-160d071ff741","added_by":"auto","created_at":"2024-03-05 19:03:39","extension":"jpeg","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":103064,"visible":true,"origin":"","legend":"\u003cp\u003eInjection Pressure in Glass Micromodel II \u003cstrong\u003e(A)\u003c/strong\u003e During crude oil injection after gelation \u003cstrong\u003e(B)\u003c/strong\u003e During brine injection after gelation\u003c/p\u003e","description":"","filename":"image11.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-3975156/v1/d55421487d41f0abcf133b95.jpeg"},{"id":66597226,"identity":"b33503e1-5504-4895-8581-a3397b86abb5","added_by":"auto","created_at":"2024-10-14 16:08:40","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4233217,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3975156/v1/cf349346-0a4b-4161-99e7-0798dceccf8d.pdf"},{"id":52043840,"identity":"48d2853c-e83f-4276-91de-9d2e86635672","added_by":"auto","created_at":"2024-03-05 19:03:39","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":78007,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryMaterial.docx","url":"https://assets-eu.researchsquare.com/files/rs-3975156/v1/51a8d8b306a5248cb14fa8fe.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Visualizing Conformance Control Mechanisms in High-Temperature Reservoirs: A Microfluidic Analysis of Pickering Emulsified Gel Systems","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eThe comprehensive study of multiphase flow in porous media holds paramount significance across various industries, with particular prominence in the oil and gas sector. Reservoirs, inherently porous in nature, serve as reservoirs for hydrocarbons, where the multiphase flow of oil, gas, and water plays a pivotal role (Alhammadi et al., 2017).\u003c/p\u003e\n\u003cp\u003eUnderstanding the intricate dynamics of multiphase flow in porous media is critical for the successful implementation of enhanced oil recovery techniques, conformance control strategies, waterflooding processes, and more (Auset and Keller, 2004; Gupta et al., 2011; Sohrabi et al., 2015; Tanzil et al., 2002; Tavassoli et al., 2016) (Asadi-Saghandi et al., 2022). Excessive water production from oil wells poses a substantial challenge, particularly in mature wells (Saikia et al., 2019). Water shut-off operations, originally devised to mitigate excessive water production, have been adapted to address conformance issues by ameliorating reservoir heterogeneity (Divandari et al., 2021; Goudarzi et al., 2015).\u003c/p\u003e\n\u003cp\u003eIn the realm of water shut-off and conformance control, chemical treatment methods have taken center stage. These methods employ a repertoire of agents, including in-situ gels, polymers, water swelling polymers, micro matrix cement, and HWSO plugging agents, to curtail water production and enhance conformance in oil wells (Dai et al., 2011) (Alain Zaitoun et al., 2007) (Bai et al., 2008) (Peirce et al., 2014) (Liu et al., 2010) (SUN and BAI, 2017) (Yin et al., 2022).\u003c/p\u003e\n\u003cp\u003eCore flooding experiments, a conventional technique, are commonly employed to investigate multiphase flow in realistic porous materials (Cuthiell et al., 1993; Qi et al., 2017). These experiments yield macro-scale data, including pressure variations, fluid saturation profiles, and produced fluid properties, offering insights into multiphase flow behavior within porous rocks. However, the complex 3D geometry of core sections presents challenges for direct visualization of micron-scale multiphase flow.\u003c/p\u003e\n\u003cp\u003eTo address this limitation, advanced techniques such as medical CT scans and NMR spectroscopy have been employed to complement core flooding experimental results (Cuthiell et al., 1993) (Siavashi et al., 2022). Nevertheless, these techniques do not provide dynamic, high-resolution micron-scale visualization of multiphase flow within core sections during experiments (Xu et al., 2017).\u003c/p\u003e\n\u003cp\u003eConversely, chemical water shut-off and conformance control agents, including those previously mentioned, have primarily been tested in core flooding setups, often supported by medical CT scans, NMR spectroscopy, and simulation studies. Researchers have proposed various conformance mechanisms based on their findings. Some posit that polymer microgels selectively invade high-permeability layers while avoiding low-permeability layers due to their low viscosity and steric effects (Cozic et al., 2009) (Seright et al., 2012). Others suggest that microgels show minimal penetration in low-permeability layers owing to their large size (A. Zaitoun et al., 2007).\u003c/p\u003e\n\u003cp\u003eDivergent conformance mechanisms have also been proposed, such as the Disproportionate Permeability Reduction (DPR) or Relative Permeability Modification (RPM) effect, which involves microgels compressing under water-oil capillary pressure, selectively reducing water permeability (Chauveteau et al., 2004) (Rousseau et al., 2005). Additionally, the mechanism of microscopic diversion suggests that rigid polymer microgel colloids promote the recovery of capillary-trapped residual oil through pore-blocking-induced redistribution of flow (Spildo et al., 2009).\u003c/p\u003e\n\u003cp\u003eSimilar proposals exist for other conformance control chemical treatment methods, all originating from experimental results obtained via core flooding experiments, pressure variations, permeability reduction, residual oil saturation, effluent profiles, and more (Cozic et al., 2009) (A. Zaitoun et al., 2007). These disputes regarding conformance control mechanisms can be resolved through the application of microfluidic analysis, which allows for the efficient study and visualization of micron-scale multiphase flow. Glass micromodels, designed to emulate the pore structures of subsurface rocks, provide a promising avenue for such investigations.\u003c/p\u003e\n\u003cp\u003eIn our previous work, we developed an invert Pickering emulsified gel system designed for high-temperature reservoirs. This system, tested as a conformance control mechanism, demonstrated the ability to curtail water production while preserving oil flow (Saikia et al., 2021, 2020; Saikia and Sultan, 2020). Utilizing core flooding experiments and microcomputed tomography (CT) imaging, we postulated the \u0026quot;Thin Film conformance control mechanism\u0026quot; based on experimental data.\u003c/p\u003e\n\u003cp\u003eThe current research endeavors employ microfluidic glass micromodels to delve into the intricacies of conformance control mechanisms. Our objective is to gain a profound understanding of these mechanisms and validate the hypothesized \u0026quot;Thin Film conformance mechanism.\u0026quot; To the best of our knowledge, this represents the pioneering study to utilize glass micromodels for elucidating conformance control mechanisms.\u003c/p\u003e"},{"header":"2. Experimental Section","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003e2.1 Materials\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe emulsion system developed and used as a conformance control system was an invert Pickering emulsion. The continuous phase is the oleic phase (diesel oil), and the dispersed phase is the aqueous phase (gelant). The diesel oil was purchased from the local gas station. The density and viscosity of the diesel oil was 0.832kg/L and 1.6cP respectively. The crude oil used in this work was Arabian heavy crude oil with a density of 890 kg/m\u003csup\u003e3\u0026nbsp;\u003c/sup\u003eand 170 Cp of zero shear viscosity at 25℃ (Figure \u003cstrong\u003eS1\u003c/strong\u003e). The gelant or aqueous phase is a mixture of polyacrylamide (PAM) and polyethylenimine (PEI). The PAM was purchased from SNF Floerger, France and PEI from MPI Biomedicals. The PAM is used in powdered form having a molecular weight of 4.5-7.5 MDa. The PEI solution was 50% aqueous solution with a molecular weight and density of 43 kDa and 1.07 g/mL respectively. The PEI is used as a crosslinker for gelation in the emulsion system. The desired emulsion stability was obtained with the help of Cloisite 20, which is an organically modified phyllosilicate. The Cloisite 20 is used as an emulsifier in the emulsion system and obtained from BYK, U.K. The Cloisite 20 have a particle size of D50 \u0026lt; 10 \u0026micro;m and a density of 1.80 g/cm\u003csup\u003e3\u003c/sup\u003e (at 20 ℃). The PAM and PEI solution was prepared using field mixing water obtained from a local operating company. The TDS in the field mixing water was maintained at 976.2 with the composition shown in Table S1.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e2.2 Proposed (postulate) Thin Film Conformance Control Mechanism (during core flooding experiments)\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe proposed \u0026quot;Thin Film\u0026quot; conformance control mechanism is depicted comprehensively in \u003cstrong\u003eFigure 1\u003c/strong\u003e. The process commences with the injection of an invert Pickering emulsion into the reservoir region characterized by high water cut, as illustrated in \u003cstrong\u003eFigure 1A\u003c/strong\u003e. The formulation of this invert emulsion system is engineered to facilitate its breakdown into distinct oleic and aqueous phases, driven by the elevated temperature of 105\u0026deg;C. This temperature regime closely emulates the conditions prevailing in high-temperature oil wells.\u003c/p\u003e\n\u003cp\u003eUpon breakdown, the separated aqueous phase undergoes a phase transition into a gel-like state at higher temperatures, effectively occupying the central void spaces within the pore channels. Concurrently, the isolated oil phase envelops the gel phase, resulting in the formation of a thin, oil-rich layer encompassing the gel, as exemplified in \u003cstrong\u003eFigure 1B\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003eSubsequently, during the post-treatment backflow phase, the crude oil readily traverses the Thin Film segment due to its favorable miscibility with diesel oil. In contrast, the formation brine exhibits non-miscibility with diesel oil within the Thin Film. Consequently, the brine is compelled to displace the entire diesel oil residing within the Thin Film to facilitate its own flow, as depicted in \u003cstrong\u003eFigure 1C\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003eNotably, within the context of multiphase flow, fluids with lower resistance inherently take precedence. Thus, this emulsified gel treatment strategy orchestrates a dynamic that aligns with the principle of least resistance, ultimately delivering the targeted conformance control and effecting the desired relative permeability modification.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e2.3 Microfluidic Glass Micromodel\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn this research endeavor, two distinct glass micromodels were meticulously employed for experimentation, as illustrated in \u003cstrong\u003eFigure 2\u003c/strong\u003e. The initial glass micromodel, referred to as \u0026quot;micromodel I,\u0026quot; embodies a homogeneous structure characterized by a circular grain geometry with a diameter of 136 \u0026micro;m, effectively emulating the rock structure within the micromodel (\u003cstrong\u003eFigure 2A \u0026amp; 2B\u003c/strong\u003e). The inter-grain spacing, set at 63 \u0026micro;m, faithfully replicates pore throat dimensions. The entirety of the circular grain configuration spans 14mm in length and 7.27 mm in width. Maintaining a pore channel depth of 0.011mm, this model exhibits a porosity of 65% and houses a total pore volume of 0.72 \u0026micro;L.\u003c/p\u003e\n\u003cp\u003eConversely, the second glass micromodel, denominated as \u0026quot;micromodel-II,\u0026quot; introduces a heterogeneous paradigm that mirrors a more realistic rock matrix pattern interspersed with high-permeability fractures, as vividly depicted in \u003cstrong\u003eFigure 2C \u0026amp; 2D\u003c/strong\u003e. This glass micromodel extends over dimensions of 4.415 mm in length and 3.302 mm in width, with both fractures and pore spaces sharing a common depth of 0.011 mm. The fractures themselves boast a width of 100 \u0026micro;m. Micromodel II exhibits a porosity of 52% and possesses a pore volume measuring 0.08 \u0026micro;L.\u003c/p\u003e\n\u003cp\u003eTo bring these glass micromodels to fruition, we leveraged high-resolution photolithographic masks provided by CAD Art Services, USA. The fabrication process followed established photolithography procedures, complemented by hydrofluoric acid etching techniques (Xu et al., 2017). Furthermore, a chloro-dimethyloctylsilane coating was applied, rendering glass micromodel I water-wet, while glass micromodel II adopted an oil-wet nature (Mejia et al., 2019).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e2.4 Microfluidic Experimental setup\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe experimental procedures were meticulously executed within a meticulously self-assembled microfluidic setup. Fluid infusion was adeptly facilitated by a Harvard Apparatus PhD 2000 syringe pump. To capture intricate details of the glass micromodels in real-time, we harnessed the capabilities of the Meros high-speed digital microscope. This advanced microscope is outfitted with high-power LED coaxial illumination, boasting an impressive frame rate of approximately 4100 frames per second (fps). Seamless integration with computer systems enabled streamlined data acquisition and analysis.\u003c/p\u003e\n\u003cp\u003eFor the fluidic connections between the system components, we employed 1/16-inch OD tubing crafted from PFA (perfluoroalkoxy). This choice of material ensures compatibility with the glass micromodels while maintaining the integrity of the experimental setup.\u003c/p\u003e\n\u003cp\u003eIn the context of pressure monitoring, the uProcess pressure sensors emerged as indispensable tools. These sensors possess a commendable pressure measurement range spanning from 0 to 250 Kpa, and they were strategically deployed to measure pressure levels within the inlet line feeding into the glass micromodel. Collectively, this ensemble of specialized equipment and instrumentation facilitated the precise execution and data acquisition of our microfluidic experiments.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e2.5 Experimental procedure\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn this research undertaking, the glass micromodels underwent a meticulous pre-treatment process to emulate the conditions prevailing in reservoir zones with high water production issues. Initially, full saturation of the glass micromodels was achieved using field mixing water, closely mirroring the reservoir conditions. The introduction of field mixing water into the glass micromodels was expertly executed via a gas-tight syringe, specifically the Hamilton 250\u0026micro;L Model 1725 TLL SYR, operating at a controlled flow rate of 50\u0026micro;L/hr. Towards the latter stages of the field mixing water (brine) injection, the flow rate was elevated to 100 \u0026micro;L/hr to dislodge any residual air bubbles trapped within the glass micromodel.\u003c/p\u003e\n\u003cp\u003eFollowing the successful saturation of the glass micromodels with field mixing water, the specially developed Pickering emulsified gel system was introduced into the system at a consistent flow rate of 50 \u0026micro;L/hr. The formulation and emulsification process of this Pickering emulsified gel system have been extensively detailed in Saikia et al., 2019. Approximately 2 pore volumes of the Pickering emulsified gel system were meticulously injected into the glass micromodels.\u003c/p\u003e\n\u003cp\u003ePost-emulsion injection, the glass micromodels were subjected to a controlled temperature of 105℃, skillfully maintained using a hot plate. This temperature exposure spanned a duration of 24 hours. The inherent design of the Pickering emulsified gel system ensured that, during this period, the emulsion would undergo phase separation, resulting in the formation of distinct aqueous and oleic phases (Saikia et al., 2021, 2019). The aqueous phase subsequently underwent a transformation into a rigid gel structure, serving as a formidable impediment to the flow of the formation water.\u003c/p\u003e\n\u003cp\u003eUpon successful gelation, diesel or crude oil was introduced into the glass micromodels at carefully regulated flow rates of 50 \u0026micro;L/hr and 100 \u0026micro;L/hr. The ensuing experiments meticulously monitored and scrutinized the flow behavior and pressure variations during both the diesel/crude oil injection and the subsequent introduction of field mixing water (brine). This comparative analysis shed light on the contrasting dynamics between the two fluid injections, providing valuable insights into the conformance control mechanisms at play.\u003c/p\u003e"},{"header":"3. Results and Discussion","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003e3.1 Conformance Control Mechanism in Glass Micromodel I\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn this research study, the physical state of the emulsion system before its injection into the glass micromodel is depicted in \u003cstrong\u003eFigure 4(A)\u003c/strong\u003e. The emulsion comprises an aqueous phase (PAM+PEI) dispersed within a continuous oleic phase. Notably, the emulsion droplets exhibit non-uniform spherical characteristics. The hypothesized conformance control mechanism (\u003cstrong\u003eFigure 1\u003c/strong\u003e) posited that these emulsion droplets would enter the pore channels in their droplet form. However, during the actual injection into the glass micromodel (\u003cstrong\u003eFigure 4B \u0026amp; 4C\u003c/strong\u003e), an unexpected phenomenon transpired. The emulsion droplets began coalescing prior to reaching the pore matrix section within the glass micromodel. This premature coalescence can be attributed to the substantial shear stress encountered during the injection process. Consequently, the emulsion droplets transformed into a dispersed aqueous slug (comprising the major portion) and dispersed aqueous drops (constituting the minor portion) within the glass micromodel. Additionally, it was observed that minimal coalescence of the aqueous slug or droplets occurred during the subsequent 24-hour shut-in period at the elevated temperature of 105℃. In \u003cstrong\u003eFigure 4(C)\u003c/strong\u003e, a distinct gelled aqueous phase, manifesting as slugs and drops, effectively obstructed the pore space within the glass micromodel matrix. Meanwhile, the separated oleic phase occupied the remaining matrix space, potentially providing a pathway for oil flow.\u003c/p\u003e\n\u003cp\u003eFollowing the successful gelation of the aqueous phase, crude oil was introduced into the glass micromodel to elucidate the flow path. Contrary to the anticipated behavior posited in the hypothesized mechanism (\u003cstrong\u003eFigure 1B\u003c/strong\u003e), the observed oil flow in the glass micromodel exhibited an unexpected pattern. Notably, the postulated Thin Film structure was conspicuously absent following gelation (shut-in period), and the oil primarily flowed through two discernible macroscopic channels, as depicted in \u003cstrong\u003eFigure 5\u003c/strong\u003e. This outcome diverged significantly from the anticipated \u0026quot;Thin Film mechanism.\u0026quot;\u003c/p\u003e\n\u003cp\u003eSubsequent experiments involving the injection of both crude oil and diesel oil aimed to ascertain whether altering the type of oleic phase would impact miscibility or flow patterns. It was observed that crude oil and diesel oil exhibited a high degree of miscibility, facilitating smooth flow through the designated oil channels. This observation was further corroborated by the accompanying video evidence (\u003cstrong\u003eVideo 1\u003c/strong\u003e).\u003c/p\u003e\n\u003cp\u003eTo further probe the conformance control mechanism of the emulsified gel system, field mixing water (brine) was introduced into the glass micromodel (\u003cstrong\u003eFigure 6\u003c/strong\u003e). It became evident that the injected brine struggled to identify alternative flow paths within the glass micromodel other than the oil channel. Consequently, the brine flowed through the oil channel, displacing the oil towards the outlet, as depicted in \u003cstrong\u003eFigure 6(A)\u003c/strong\u003e with black arrows indicating the brine flow path. Even after water breakthrough, the brine encountered resistance compared to the relatively unhindered oil flow. The brine became entrapped within the pore matrix, while the oil continued to flow with minimal resistance through the available space between the blocked brine and matrix grains (\u003cstrong\u003eFigure 6B\u003c/strong\u003e). A similar trend was observed in \u003cstrong\u003eFigure 6C, 6D, and 6E\u003c/strong\u003e, where during brine injection, the diesel oil was displaced from the glass micromodel, resulting in continuous flow with minimal resistance. However, once water breakthrough occurred, the flow pattern abruptly changed, with intermittent brine flow through the same channel indicating increased resistance encountered by the brine after treatment with the Pickering emulsified gel. These flow patterns are further elucidated in \u003cstrong\u003eVideos 2 and 3\u003c/strong\u003e. Consistent findings were also reflected in the pressure measurement data, as presented in \u003cstrong\u003eFigure 7A \u0026amp; 7B\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003eDuring diesel oil injection post-gelation, the injection commenced at a flow rate of 50 \u0026micro;L/hr, with an initial pressure of approximately 32 Kpa (\u003cstrong\u003eFigure 7A\u003c/strong\u003e). After about 5 minutes, the pressure stabilized at approximately 150 Kpa, prompting an increase in the injection flow rate to 100 \u0026micro;L/hr. This change led to a subsequent increase in pressure to approximately 190 Kpa within the following 3 minutes. Subsequently, the pressure remained constant at 190 Kpa for an additional 18 minutes.\u003c/p\u003e\n\u003cp\u003eSimilarly, during field mixing water (brine) injection into the micromodel at a flow rate of 50 \u0026micro;L/hr, a steep increase in pressure reading was observed, escalating from 51 Kpa to 250 Kpa (\u003cstrong\u003eFigure 7B\u003c/strong\u003e). The injection flow rate was maintained at 50 \u0026micro;L/hr for 10 minutes, during which the pressure reading remained constant at 250 Kpa. This value persisted even after the brine breakthrough. While the pressure reading may have surpassed this value, the pressure sensors\u0026apos; upper limit capped it at 250 Kpa. Subsequently, the injection flow rate was increased to 100 \u0026micro;L/hr for an additional 15 minutes, with no noticeable variation in pressure readings. Comparing both pressure profiles during oil and brine injection, it is evident that brine encountered significant resistance during its flow. Notably, the maximum injection pressure recorded during oil injection was 190 Kpa, while it reached 250 Kpa during brine injection. This resistance to flow can be attributed to the gel treatment\u0026apos;s role as a relative permeability modifier.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e3.2 Conformance Control Mechanism in Glass Micromodel II\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn the case of glass micromodel II, the initial step involved saturating it with field mixing water, as illustrated in \u003cstrong\u003eFigure 8A\u003c/strong\u003e. During the subsequent injection of Pickering emulsified gel, a distinctive behavior was observed. Within glass micromodel II, the emulsion system entered the matrix primarily in the form of substantial aqueous phase slugs accompanied by small quantities of aqueous phase drops dispersed within a continuous oil phase (\u003cstrong\u003eFigure 8B\u003c/strong\u003e). This phenomenon is visually demonstrated in the attached \u003cstrong\u003evideo 4\u003c/strong\u003e. Following the emulsion injection, the glass micromodel was subjected to a temperature of 105℃, placed atop a hot plate, for 24 hours. During this period, the aqueous phase underwent a transition into a gel phase, occupying a significant portion of the pore space within the matrix, while the remaining space was filled by the separated oleic phase (\u003cstrong\u003eFigure 8C\u003c/strong\u003e).\u003c/p\u003e\n\u003cp\u003eSubsequent injection of crude oil into glass micromodel II revealed a unique flow pattern. Contrary to the anticipated Thin Film mechanism, the injected crude oil predominantly flowed through a single fracture, resembling a channel flow. Most of the matrix space remained blocked by the rigid gel, except for the specified fracture. \u003cstrong\u003eFigure 9A\u003c/strong\u003e illustrates the initial state of the glass micromodel during crude oil injection, while \u003cstrong\u003eFigure 9B\u003c/strong\u003e represents the state at the conclusion of the crude oil injection. Remarkably, minimal deviation in the crude oil flow path occurred throughout the entire injection process. A macroscopic view of glass micromodel II after the experiment is presented in \u003cstrong\u003eFigure 9(C)\u003c/strong\u003e. Notably, the injected crude oil primarily followed a solitary flow path through the fracture. A notable observation was the change in crude oil color during the injection, shifting from lighter shades at the beginning to darker tones towards the end. This color alteration was attributed to the fact that the flow channel had initially been occupied by diesel oil, a component separated from the emulsion system. Consequently, the injected crude oil exhibited miscibility with the diesel oil, enabling a continuous flow through the channel, as evident in \u003cstrong\u003evideo 5\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003eFollowing the conclusion of the crude oil injection stage, field mixing water (brine) was introduced into glass micromodel II. During brine injection, behavior analogous to that observed in glass micromodel I was evident. The injected brine struggled to identify alternative pathways within the micromodel, primarily following the crude oil flow path. This brine flow path is indicated by white arrows in \u003cstrong\u003eFigure 10\u003c/strong\u003e. While the brine displaced the crude oil from the oil channel, it failed to entirely displace it. The brine exhibited intermittent flow within the channel, as seen in \u003cstrong\u003evideo 6\u003c/strong\u003e. This intermittent behavior could be attributed to the oil-wet wettability of glass micromodel II. Consequently, in glass micromodel II, the brine intermittently encountered flow resistance compared to the continuous crude oil flow. Even after the brine breakthrough, the crude oil continued to flow continuously. Moreover, the brine exerted pressure, compelling the crude oil out of the flow channels. \u003cstrong\u003eFigure 10\u003c/strong\u003e visually depicts this behavior, with yellow arrows indicating the crude oil\u0026apos;s displacement to previously unoccupied areas of the glass micromodel.\u003c/p\u003e\n\u003cp\u003ePressure profiles during both crude oil and brine injection within glass micromodel II are illustrated in \u003cstrong\u003eFigure 11\u003c/strong\u003e. During the initial crude oil injection phase, maintained at a flow rate of 50 \u0026micro;L/hr, the pressure reading increased from 30 Kpa to 93 Kpa within 3 minutes. Subsequently, the pressure stabilized at 93 Kpa (\u003cstrong\u003eFigure 11A\u003c/strong\u003e). Upon increasing the injection flow rate to 100 \u0026micro;L/hr, the pressure rapidly rose from 93 Kpa to 155 Kpa within 3 minutes. Despite maintaining the flow rate at 100 \u0026micro;L/hr for an additional 18 minutes, the pressure remained constant at 155 Kpa.\u003c/p\u003e\n\u003cp\u003eIn contrast, during the transition to brine injection, maintained at 50 \u0026micro;L/hr, the pressure exhibited a steeper ascent, surging from 51 Kpa to 250 Kpa (\u003cstrong\u003eFigure 11B\u003c/strong\u003e). This pressure rise transpired within 18 minutes of brine injection. Subsequently increasing the flow rate to 100 \u0026micro;L/hr failed to elicit any noticeable change in pressure readings, with the pressure consistently maintained at the peak value of 250 Kpa. The discernible difference in peak injection pressures between crude oil and brine injection at equivalent flow rates underscores the resistance encountered by the brine during its flow through glass micromodel II relative to the crude oil. Brine injection persisted for approximately 60 minutes, yet the pressure reading remained capped at 250 Kpa, reflecting the pressure sensors\u0026apos; upper limit. Additionally, \u003cstrong\u003evideo 6\u003c/strong\u003e confirmed the intermittent flow of brine within the channel, highlighting the reduced relative permeability of brine following gel treatment. In contrast, oil relative permeability remained unaffected. The findings align with those observed during core flooding experiments conducted using the same Pickering emulsified gel system (Saikia et al., 2021) (Saikia et al., 2019), suggesting that the originally postulated conformance control mechanism only partially holds. While the hypothesis of emulsion separation and aqueous phase gelling was confirmed, the Thin Film mechanism was debunked. Instead, the newly proposed conformance control mechanism involving Relative Permeability Modified Channel Flow, as observed in the experiments, and discussed in the results, presents a more accurate representation. Under this mechanism, following gel treatment, crude oil flows continuously through the diesel oil channel, whereas brine flow remains intermittent.\u003c/p\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eThis research endeavor has yielded several valuable insights into the conformance control mechanism employing an invert Pickering emulsion, as investigated through two distinct glass micromodels. The following conclusions can be deduced from this comprehensive study:\u003c/p\u003e\n\u003col\u003e\n \u003cli\u003eIn contrast to the initially hypothesized Thin Film mechanism, it was observed that the emulsified gel system predominantly infiltrates the matrix space in the form of emulsion slugs.\u003c/li\u003e\n \u003cli\u003eCoalescence of emulsion droplets occurred during the injection process, resulting in the gelling of the aqueous phase within the micromodel\u0026apos;s matrix space, particularly under elevated temperature conditions. This behavior contradicts the formation of clearly distinguishable aqueous gel phases within the central pore space and surrounding oleic Thin Films, as envisaged in the Thin Film mechanism.\u003c/li\u003e\n \u003cli\u003eCrude oil exhibited a distinctive flow pattern, traversing specific flow channels created by the separated emulsion oleic phase, facilitated by their miscibility. This flow behavior deviates from the anticipated Thin Film flow.\u003c/li\u003e\n \u003cli\u003eDuring brine injection, the injected brine struggled to locate alternative flow channels, instead being confined to the crude oil flow channel. Consequently, brine flow exerted pressure on the oil within the channel, propelling it towards the outlet or the remaining matrix space in the micromodel, owing to the immiscibility of the two phases.\u003c/li\u003e\n \u003cli\u003eThe flow of injected brine within the flow channel remained intermittent even after achieving brine breakthrough within the micromodels.\u003c/li\u003e\n \u003cli\u003eImportantly, brine encountered notable flow resistance within the flow channels, resulting in higher injection pressure readings during brine flow at equivalent injection flow rates compared to crude oil flow.\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003eTaken together, these observations conclusively demonstrate that the originally postulated Thin Film conformance control mechanism is only partially accurate. This microfluidic investigation has provided valuable insights into the authentic conformance mechanism governing conformance control and water shut-off treatments.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgment\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors would like to acknowledge King Fahd University of Petroleum \u0026amp; Minerals for providing necessary laboratory facilities.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDr. Tinku Saikia*(Corresponding Author)\u003c/p\u003e\n\u003cp\u003eEmail- \u003cu\[email protected]\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003eDr. Abdullah Sultan\u003c/p\u003e\n\u003cp\u003eEmail - [email protected]\u003c/p\u003e\n\u003cp\u003eDr. Matthew Balhoff\u003c/p\u003e\n\u003cp\u003eEmail - [email protected]\u003c/p\u003e\n\u003cp\u003eDr. Lucas Mejia\u003c/p\u003e\n\u003cp\u003eEmail - \u003cu\[email protected]\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003eMr. Jafar Sadeq Al Hamad\u003c/p\u003e\n\u003cp\u003eEmail: [email protected]\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding Information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAlhammadi, A.M., Alratrout, A., Singh, K., Bijeljic, B., Blunt, M.J., 2017. 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Lab Chip. https://doi.org/10.1039/c6lc01476c\u003c/li\u003e\n\u003cli\u003eYin, H., Yin, X., Cao, R., Zeng, P., Wang, J., Wu, D., Luo, X., Zhu, Y., Zheng, Z., Feng, Y., 2022. In situ crosslinked weak gels with ultralong and tunable gelation times for improving oil recovery. Chem. Eng. J. https://doi.org/10.1016/j.cej.2021.134350\u003c/li\u003e\n\u003cli\u003eZaitoun, Alain, Kohler, N., Montemurro, M.A., 2007. Control of Water Influx in Heavy-Oil Horizontal Wells by Polymer Treatment. https://doi.org/10.2523/24661-ms\u003c/li\u003e\n\u003cli\u003eZaitoun, A., Tabary, R., Rousseau, D., Pichery, T., Nouyoux, S., Mallo, P., Braun, O., 2007. Using microgels to shut off water in a gas storage well, in: Proceedings - SPE International Symposium on Oilfield Chemistry. https://doi.org/10.2118/106042-ms\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Videos","content":"\u003cp\u003eVideos 1 to 6 are not available with this version.\u003c/p\u003e "}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"microfluidics-and-nanofluidics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"mano","sideBox":"Learn more about [Microfluidics and Nanofluidics](http://link.springer.com/journal/10404)","snPcode":"10404","submissionUrl":"https://submission.nature.com/new-submission/10404/3","title":"Microfluidics and Nanofluidics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Conformance Control, Water shut-off, Emulsified Gel, Microfluidic.","lastPublishedDoi":"10.21203/rs.3.rs-3975156/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3975156/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"In the context of mature oil fields, the management of conformance control and water shut-off stands out as a formidable challenge. Our prior research endeavors (Saikia et al., 2021, 2020) have introduced an innovative Pickering emulsified gel system tailored for the precise adjustment of relative permeability in high-temperature reservoirs. To optimize the efficiency of this system, a comprehensive comprehension of the underlying conformance control mechanism is deemed imperative. Traditionally, the exploration of conformance control mechanisms leans on empirical data culled from core flooding experiments, computerized tomography (CT) scans, nuclear magnetic resonance spectroscopy (NMR), and analogous methodologies. Nevertheless, these conventional avenues often fall short in delivering real-time visual analyses, thereby raising doubts about their reliability in predicting conformance mechanisms. In our research study, we have harnessed the capabilities of microfluidics to unlock real-time visual insights into the mechanisms governing conformance control. Employing two distinct glass micromodel geometries, we have conducted Pickering emulsified gel treatments at a scorching 105°C to achieve the targeted conformance control within these micromodels. By synergizing image and video analysis with injection pressure measurements, our findings have cast doubt on the previously posited Thin Film conformance control mechanism, revealing a more nuanced perspective on this intricate process.","manuscriptTitle":"Visualizing Conformance Control Mechanisms in High-Temperature Reservoirs: A Microfluidic Analysis of Pickering Emulsified Gel Systems","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-03-05 19:03:34","doi":"10.21203/rs.3.rs-3975156/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-09-16T06:16:21+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-09-15T07:32:45+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-09-10T18:21:56+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-08-31T11:33:35+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"101953889979614725995669806946231757972","date":"2024-08-28T14:35:43+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"12407923264049911892937776300068854149","date":"2024-08-26T17:27:52+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"6848618818400574510269492646681077442","date":"2024-08-26T14:45:43+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"283130547694798344228554380372048084290","date":"2024-07-25T20:39:58+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-05-08T11:45:50+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"212031326900787919002616646177356345616","date":"2024-05-03T11:41:13+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"63385a05-c937-4176-8f1d-7ed49ea1b9a6","date":"2024-04-25T20:12:56+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"0c6e391f-dfd5-4634-9210-9d0366fd5ce8","date":"2024-04-17T11:59:58+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-03-02T10:41:59+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-02-26T02:19:46+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-02-24T01:07:56+00:00","index":"","fulltext":""},{"type":"submitted","content":"Microfluidics and Nanofluidics","date":"2024-02-21T09:59:41+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"microfluidics-and-nanofluidics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"mano","sideBox":"Learn more about [Microfluidics and Nanofluidics](http://link.springer.com/journal/10404)","snPcode":"10404","submissionUrl":"https://submission.nature.com/new-submission/10404/3","title":"Microfluidics and Nanofluidics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"1d3f0ec4-1da1-4d92-8a6c-f54a78fed540","owner":[],"postedDate":"March 5th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-10-14T16:02:55+00:00","versionOfRecord":{"articleIdentity":"rs-3975156","link":"https://doi.org/10.1007/s10404-024-02770-8","journal":{"identity":"microfluidics-and-nanofluidics","isVorOnly":false,"title":"Microfluidics and Nanofluidics"},"publishedOn":"2024-10-12 15:57:54","publishedOnDateReadable":"October 12th, 2024"},"versionCreatedAt":"2024-03-05 19:03:34","video":"","vorDoi":"10.1007/s10404-024-02770-8","vorDoiUrl":"https://doi.org/10.1007/s10404-024-02770-8","workflowStages":[]},"version":"v1","identity":"rs-3975156","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3975156","identity":"rs-3975156","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}