The study investigates the spatiotemporal evolution of multi-scale crack damage fractures in shale fracturing by employing a combination of acoustic emission and CT scanning techniques

The study investigates the spatiotemporal evolution of multi-scale crack damage fractures in shale fracturing by employing a combination of acoustic emission and CT scanning techniques | 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 Article The study investigates the spatiotemporal evolution of multi-scale crack damage fractures in shale fracturing by employing a combination of acoustic emission and CT scanning techniques Xu Wei, Meng Cai, Cuilong Kong, Dezhao Zhao This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6204084/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 24 Dec, 2025 Read the published version in Scientific Reports → Version 1 posted 10 You are reading this latest preprint version Abstract Volume fracturing technology is a pivotal technical approach for enhancing the development of shale oil. It creates complex fracture networks influenced by factors such as the anisotropy of shale, bedding planes, and the extent of natural fractures. Despite its significance, the spatiotemporal evolution of multi-scale crack damage during shale fracturing, under varying in-situ geostress differences and construction parameters, remains unclear. To address this, this study introduces an experimental method that integrates CT scanning and acoustic emission monitoring to examine the full expansion process of fracturing. The method employs 300mm×300mm×300mm rock samples subjected to different in-situ geostress differences and construction parameters. The study clarifies the crack propagation morphology and quantity at various times and quantitatively describes the crack stimulation area before and after fracturing. The findings suggest that shale with lower minimum horizontal stress is more susceptible to crack initiation. Under high in-situ geostress differences, reservoirs with well-developed bedding planes tend to form vertical fractures, a phenomenon attributable to the stress concentration effect on these planes. An increase in injection rate from 35ml/min to 50ml/min led to a 159% increase in fracturing crack height, from 7.1cm to 18.4cm, indicating that higher injection rates promote deeper crack penetration by increasing fluid pressure and reducing stress concentration at the fracture tip. Similarly, increasing the fracturing fluid's viscosity from 2mPa·s to 50mPa·s resulted in a 52% increase in crack height, from 7.1cm to 10.8cm, highlighting the benefit of higher viscosity in reducing filtration loss and maintaining injection pressure. The combined use of high and low viscosity fracturing fluids (5:5 ratio) leverages the advantages of both approaches: forming long and high main fractures to overcome near-wellbore bedding plane constraints and then activating additional bedding planes to enhance reservoir stimulation efficiency. This research offers a theoretical foundation for optimizing fracturing crack propagation morphology and construction parameters in shale reservoirs with significant bedding planes. Physical sciences/Energy science and technology Physical sciences/Engineering Acoustic emission CT scanning The spatiotemporal evolution law of damage fracture Crack stimulation area Bedding planes Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 24 Dec, 2025 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 05 May, 2025 Reviews received at journal 23 Apr, 2025 Reviews received at journal 19 Apr, 2025 Reviewers agreed at journal 05 Apr, 2025 Reviewers agreed at journal 04 Apr, 2025 Reviewers invited by journal 26 Mar, 2025 Editor assigned by journal 18 Mar, 2025 Editor invited by journal 18 Mar, 2025 Submission checks completed at journal 17 Mar, 2025 First submitted to journal 11 Mar, 2025 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. 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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-6204084","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":438906695,"identity":"ac63dae6-702a-4f4b-9ec7-ea362402580f","order_by":0,"name":"Xu Wei","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAy0lEQVRIiWNgGAWjYFACxgYGhgoJHn72xsYHH4jXcsZGRrLncLPhDOItakuzMbiR3ibNQYxqg+PNbdI8bId5DG4+bJBmYLCT020gpOXMwWZjHp7DPJK3ExuMCxiSjc0OENBidiOx8TGPxGEePqCW5BkMBxK3EdRy/2ED0FWHeRhuHgQyiNJygxFoS0IajwCQ0UyUFvszic2Gcw7Y8Ej2JDYzzjAgwi+S7cefSbz9J2HPz378+Y8PFXZyBLWgAQPSlI+CUTAKRsEowAEAWftGPjtlOnQAAAAASUVORK5CYII=","orcid":"","institution":"PetroChina Daqing Oilfield Production Technology InstitutePetroChina Daqing Oilfield Production Technology Institute","correspondingAuthor":true,"prefix":"","firstName":"Xu","middleName":"","lastName":"Wei","suffix":""},{"id":438906696,"identity":"c9fb486a-a8b7-4ea2-9793-0e65d25c9c86","order_by":1,"name":"Meng Cai","email":"","orcid":"","institution":"PetroChina Daqing Oilfield Production Technology InstitutePetroChina Daqing Oilfield Production Technology Institute","correspondingAuthor":false,"prefix":"","firstName":"Meng","middleName":"","lastName":"Cai","suffix":""},{"id":438906698,"identity":"e3467aab-8267-42d6-87ec-3cea01c7ae30","order_by":2,"name":"Cuilong Kong","email":"","orcid":"","institution":"PetroChina Daqing Oilfield Production Technology InstitutePetroChina Daqing Oilfield Production Technology Institute","correspondingAuthor":false,"prefix":"","firstName":"Cuilong","middleName":"","lastName":"Kong","suffix":""},{"id":438906699,"identity":"f9491de4-7ed0-407c-bb4c-812a6728136a","order_by":3,"name":"Dezhao Zhao","email":"","orcid":"","institution":"PetroChina Daqing Oilfield Production Technology InstitutePetroChina Daqing Oilfield Production Technology Institute","correspondingAuthor":false,"prefix":"","firstName":"Dezhao","middleName":"","lastName":"Zhao","suffix":""}],"badges":[],"createdAt":"2025-03-11 14:38:32","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6204084/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6204084/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-025-28004-7","type":"published","date":"2025-12-24T15:57:18+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":99172256,"identity":"a1175b87-a902-4a72-ae7a-e75883650bd0","added_by":"auto","created_at":"2025-12-29 16:06:18","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2044153,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6204084/v1_covered_336aef26-cc83-4c2a-9695-1742ed53ddb7.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"The study investigates the spatiotemporal evolution of multi-scale crack damage fractures in shale fracturing by employing a combination of acoustic emission and CT scanning techniques","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Acoustic emission, CT scanning, The spatiotemporal evolution law of damage fracture, Crack stimulation area, Bedding planes","lastPublishedDoi":"10.21203/rs.3.rs-6204084/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6204084/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Volume fracturing technology is a pivotal technical approach for enhancing the development of shale oil. It creates complex fracture networks influenced by factors such as the anisotropy of shale, bedding planes, and the extent of natural fractures. Despite its significance, the spatiotemporal evolution of multi-scale crack damage during shale fracturing, under varying in-situ geostress differences and construction parameters, remains unclear. To address this, this study introduces an experimental method that integrates CT scanning and acoustic emission monitoring to examine the full expansion process of fracturing. The method employs 300mm×300mm×300mm rock samples subjected to different in-situ geostress differences and construction parameters. The study clarifies the crack propagation morphology and quantity at various times and quantitatively describes the crack stimulation area before and after fracturing. The findings suggest that shale with lower minimum horizontal stress is more susceptible to crack initiation. Under high in-situ geostress differences, reservoirs with well-developed bedding planes tend to form vertical fractures, a phenomenon attributable to the stress concentration effect on these planes. An increase in injection rate from 35ml/min to 50ml/min led to a 159% increase in fracturing crack height, from 7.1cm to 18.4cm, indicating that higher injection rates promote deeper crack penetration by increasing fluid pressure and reducing stress concentration at the fracture tip. Similarly, increasing the fracturing fluid's viscosity from 2mPa·s to 50mPa·s resulted in a 52% increase in crack height, from 7.1cm to 10.8cm, highlighting the benefit of higher viscosity in reducing filtration loss and maintaining injection pressure. 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