Production Induced In Situ Stress Change and Geomechanical Dilation to Boost the Production in an Offshore Oilsands Reservoir

Production Induced In Situ Stress Change and Geomechanical Dilation to Boost the Production in an Offshore Oilsands Reservoir | 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 Production Induced In Situ Stress Change and Geomechanical Dilation to Boost the Production in an Offshore Oilsands Reservoir Jun Sun, Yunchuan Fu, Yanping Sun, Wenchao Zhou, Weiyu Chen, Zhilong Liu, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8272412/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Geomechanical dilation was implemented in an offshore cyclic steam stimulation (CSS) well in a mature oilsands reservoir to improve steam injectivity and enhance oil production. Designing such a treatment requires reliable characterization of the present-day in-situ stress state and coupled thermal–reservoir–geomechanical analysis yet stresses in thermal mature oilsands reservoirs are typically poorly constrained. In this study, the target well was tested with minifrac tests both before CSS and after an initial CSS cycle, providing rare before-and-after constraints on stress evolution. Interpretation of the two minifrac data sets indicates a reduction of ~ 3.8 MPa in the minimum horizontal stress (Shmin) near the injector, consistent with poroelastic stress relaxation caused by reservoir pore-pressure depletion. Laboratory triaxial tests at room and elevated temperatures were performed to quantify the temperature dependence of oilsands strength and stiffness. These data, together with the updated minifrac-derived stresses, were used to calibrate an iteratively coupled CMG-STARS–ABAQUS model that simulates multiphase thermal flow, geomechanical deformation, and shear-induced dilation. The coupled model was then applied to design a field-scale dilation job on the horizontal CSS well, ensuring that injection pressures exceeded the dilation threshold while remaining below the tensile breakdown pressure. Field execution of the treatment generated a laterally continuous high-permeability dilation zone around the well, reduced the surface steam-injection pressure by ~ 1.2 MPa at a designed steam injection rate, and allowed the planned steam volume to be injected without exceeding operating limits. The subsequent CSS cycle exhibited substantially higher and more sustained oil rates than the pre-dilation cycle. Overall, the results demonstrate that thermally induced stress changes can be significant in offshore oilsands reservoirs and that combining repeated minifrac measurements with coupled reservoir–geomechanical modeling provides a robust basis for designing effective, stress-informed geomechanical dilation treatments. In situ stress Oilsands reservoir Geomechanical modeling Oilsands dilation hydraulic fracturing Coupled reservoir-geomechanics simulation Minifrac Full Text Additional Declarations No competing interests reported. Supplementary Files CoverLetter1.docx Cite Share Download PDF Status: Posted Version 1 posted 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-8272412","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":563447473,"identity":"50e9de14-baba-415e-98f3-d4a0f9284f07","order_by":0,"name":"Jun Sun","email":"","orcid":"","institution":"CNOOC Key Laboratory of Offshore Heavy Oil Thermal Recovery","correspondingAuthor":false,"prefix":"","firstName":"Jun","middleName":"","lastName":"Sun","suffix":""},{"id":563447474,"identity":"0d6a2b66-87a4-4182-8a69-47d50b81aceb","order_by":1,"name":"Yunchuan 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Reservoir","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"In situ stress, Oilsands reservoir, Geomechanical modeling, Oilsands dilation, hydraulic fracturing, Coupled reservoir-geomechanics simulation, Minifrac","lastPublishedDoi":"10.21203/rs.3.rs-8272412/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8272412/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eGeomechanical dilation was implemented in an offshore cyclic steam stimulation (CSS) well in a mature oilsands reservoir to improve steam injectivity and enhance oil production. Designing such a treatment requires reliable characterization of the present-day in-situ stress state and coupled thermal\u0026ndash;reservoir\u0026ndash;geomechanical analysis yet stresses in thermal mature oilsands reservoirs are typically poorly constrained. In this study, the target well was tested with minifrac tests both before CSS and after an initial CSS cycle, providing rare before-and-after constraints on stress evolution. Interpretation of the two minifrac data sets indicates a reduction of ~\u0026thinsp;3.8 MPa in the minimum horizontal stress (Shmin) near the injector, consistent with poroelastic stress relaxation caused by reservoir pore-pressure depletion. Laboratory triaxial tests at room and elevated temperatures were performed to quantify the temperature dependence of oilsands strength and stiffness. These data, together with the updated minifrac-derived stresses, were used to calibrate an iteratively coupled CMG-STARS\u0026ndash;ABAQUS model that simulates multiphase thermal flow, geomechanical deformation, and shear-induced dilation. The coupled model was then applied to design a field-scale dilation job on the horizontal CSS well, ensuring that injection pressures exceeded the dilation threshold while remaining below the tensile breakdown pressure. Field execution of the treatment generated a laterally continuous high-permeability dilation zone around the well, reduced the surface steam-injection pressure by ~\u0026thinsp;1.2 MPa at a designed steam injection rate, and allowed the planned steam volume to be injected without exceeding operating limits. The subsequent CSS cycle exhibited substantially higher and more sustained oil rates than the pre-dilation cycle. Overall, the results demonstrate that thermally induced stress changes can be significant in offshore oilsands reservoirs and that combining repeated minifrac measurements with coupled reservoir\u0026ndash;geomechanical modeling provides a robust basis for designing effective, stress-informed geomechanical dilation treatments.\u003c/p\u003e","manuscriptTitle":"Production Induced In Situ Stress Change and Geomechanical Dilation to Boost the Production in an Offshore Oilsands Reservoir","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-22 09:25:59","doi":"10.21203/rs.3.rs-8272412/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"ec861add-aefe-44ea-a048-a4f71414bc3f","owner":[],"postedDate":"December 22nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-01T07:29:22+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-22 09:25:59","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8272412","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8272412","identity":"rs-8272412","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}