A Comprehensive Logging Evaluation Method for Identifying High-Quality Shale Gas Reservoirs Based on Multifractal Spectra Analysis

A Comprehensive Logging Evaluation Method for Identifying High-Quality Shale Gas Reservoirs Based on Multifractal Spectra Analysis | 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 A Comprehensive Logging Evaluation Method for Identifying High-Quality Shale Gas Reservoirs Based on Multifractal Spectra Analysis Xueli Bi, Juhua Li, Cuihao Lian This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4403466/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 30 Oct, 2024 Read the published version in Scientific Reports → Version 1 posted 11 You are reading this latest preprint version Abstract Conventional logging interpretation methods can help to qualitatively identify shale reservoirs using shale attribute parameters and interpretation templates. However, improving the identification accuracy of complex shale reservoirs is challenging due to the numerous evaluation parameters and the complexity of model calculations. This study examines the JY6-2 and JY10-4 wells in the Fuling shale gas field as examples to effectively quantify the characteristics of high-quality shale reservoirs. We establish a comprehensive evaluation method for identifying high-quality shale gas reservoirs, utilizing multi-fractal spectra analysis of well logs. First, the conventional well logs are qualitatively analyzed and evaluated using the methods of multiple fractals and R/S analysis. Subsequently, a gray relational analysis is employed to combine the production well logs, which reflect dimensionless productivity contributions, with the fractal characteristics of conventional well logs to obtain the corrected weight multifractal spectrum width ∆α' and the fractal dimension D'. The comprehensive fractal evaluation indexes λ and γ are introduced, forming three categories of productivity evaluation standards for shale gas reservoirs characterized by fractals. The calculation results show that the ∆α' comprehensive fractal evaluation index for Class I gas reservoirs is 0.6 λ< 1, and the D' comprehensive fractal evaluation index is 0 γ < 0.5; for Class II gas reservoirs, the ∆α' comprehensive fractal evaluation index is 0.25 λ < 0.6, and the D' comprehensive fractal evaluation index is 0.5 γ < 0.8; for Class III gas reservoirs, the ∆α' comprehensive fractal evaluation index is 0 λ < 0.25, and the D' comprehensive fractal evaluation index is 0.8 γ < 1. Overall, the comprehensive fractal evaluation index of the high-production wells ∆α' is close to 1 and shows a decreasing trend from high to low production; the comprehensive fractal evaluation index of the low-production wells with the R/S fractal dimension D' is close to 1 and shows a decreasing trend from low-production to high-production. Finally, Well JY8-2 is employed as a validation well to demonstrate the effectiveness of the evaluation method. This research method is a simple way to extract the multifractal spectra based on conventional logging data to evaluate comprehensive sweet spot zones. It is of great significance for identifying high-quality reservoir areas in shale gas reservoirs, and provides technical support for the effective development of shale reservoirs on a large scale. Physical sciences/Energy science and technology/Fossil fuels/Natural gas Earth and environmental sciences/Solid earth sciences/Geophysics Well logs Multifractal spectra R/S analysis Shale gas Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 30 Oct, 2024 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 30 Jul, 2024 Reviews received at journal 18 Jun, 2024 Reviewers agreed at journal 10 Jun, 2024 Reviews received at journal 05 Jun, 2024 Reviewers agreed at journal 30 May, 2024 Reviewers agreed at journal 26 May, 2024 Reviewers invited by journal 26 May, 2024 Editor assigned by journal 26 May, 2024 Editor invited by journal 15 May, 2024 Submission checks completed at journal 14 May, 2024 First submitted to journal 11 May, 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. 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-4403466","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":304073342,"identity":"52bf182d-a7de-4c12-8a25-5c4f513b6bc9","order_by":0,"name":"Xueli Bi","email":"","orcid":"","institution":"School of Petroleum Engineering, Yangtze University","correspondingAuthor":false,"prefix":"","firstName":"Xueli","middleName":"","lastName":"Bi","suffix":""},{"id":304073343,"identity":"83c06286-3715-4704-b64b-69c6284ffd23","order_by":1,"name":"Juhua Li","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0UlEQVRIiWNgGAWjYBACPhDxwOB/PRt784EDH34QoYUNRCQYMCfw8xxLPDizh2gtDMwJkjNyjA9zsBGjRSL5mURCAVuewY2cD4cZeBjk+cUOENKSZiaRYMBTbHDm7YbDBRYMhjNnJxDSksMG1CLBuOF47obDM3iA/rpNnBYDxg0Hch4c5mEjXktC4syOHAYitfA8M7ZIMDhgDAxkA2AgSxD2Cz978sMbH/4ckANG5eMPH37YyPNLE9ACBCwSSBwJnMqQAfMHopSNglEwCkbByAUA+zlDU+cReTAAAAAASUVORK5CYII=","orcid":"","institution":"School of Petroleum Engineering, Yangtze University","correspondingAuthor":true,"prefix":"","firstName":"Juhua","middleName":"","lastName":"Li","suffix":""},{"id":304073344,"identity":"b77a3c19-7bee-46e9-a44a-694b7d0ebb46","order_by":2,"name":"Cuihao Lian","email":"","orcid":"","institution":"School of Petroleum Engineering, Yangtze University","correspondingAuthor":false,"prefix":"","firstName":"Cuihao","middleName":"","lastName":"Lian","suffix":""}],"badges":[],"createdAt":"2024-05-11 04:26:15","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4403466/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4403466/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-024-77300-1","type":"published","date":"2024-10-30T16:20:36+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":68207387,"identity":"1234326f-7ff2-4191-ab43-cb1f0913c979","added_by":"auto","created_at":"2024-11-04 16:37:07","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":713100,"visible":true,"origin":"","legend":"","description":"","filename":"Manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4403466/v1_covered_c02d40b1-78b2-4ff7-b638-dae0a8f93174.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"A Comprehensive Logging Evaluation Method for Identifying High-Quality Shale Gas Reservoirs Based on Multifractal Spectra Analysis","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":"Well logs, Multifractal spectra, R/S analysis, Shale gas","lastPublishedDoi":"10.21203/rs.3.rs-4403466/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4403466/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eConventional logging interpretation methods can help to qualitatively identify shale reservoirs using shale attribute parameters and interpretation templates. However, improving the identification accuracy of complex shale reservoirs is challenging due to the numerous evaluation parameters and the complexity of model calculations. This study examines the JY6-2 and JY10-4 wells in the Fuling shale gas field as examples to effectively quantify the characteristics of high-quality shale reservoirs. We establish a comprehensive evaluation method for identifying high-quality shale gas reservoirs, utilizing multi-fractal spectra analysis of well logs. First, the conventional well logs are qualitatively analyzed and evaluated using the methods of multiple fractals and R/S analysis. Subsequently, a gray relational analysis is employed to combine the production well logs, which reflect dimensionless productivity contributions, with the fractal characteristics of conventional well logs to obtain the corrected weight multifractal spectrum width ∆α' and the fractal dimension D'. The comprehensive fractal evaluation indexes λ and γ are introduced, forming three categories of productivity evaluation standards for shale gas reservoirs characterized by fractals. The calculation results show that the ∆α' comprehensive fractal evaluation index for Class I gas reservoirs is 0.6 λ\u0026lt; 1, and the D' comprehensive fractal evaluation index is 0 γ \u0026lt; 0.5; for Class II gas reservoirs, the ∆α' comprehensive fractal evaluation index is 0.25 λ \u0026lt; 0.6, and the D' comprehensive fractal evaluation index is 0.5 γ \u0026lt; 0.8; for Class III gas reservoirs, the ∆α' comprehensive fractal evaluation index is 0 λ \u0026lt; 0.25, and the D' comprehensive fractal evaluation index is 0.8 γ \u0026lt; 1. Overall, the comprehensive fractal evaluation index of the high-production wells ∆α' is close to 1 and shows a decreasing trend from high to low production; the comprehensive fractal evaluation index of the low-production wells with the R/S fractal dimension D' is close to 1 and shows a decreasing trend from low-production to high-production. Finally, Well JY8-2 is employed as a validation well to demonstrate the effectiveness of the evaluation method. This research method is a simple way to extract the multifractal spectra based on conventional logging data to evaluate comprehensive sweet spot zones. It is of great significance for identifying high-quality reservoir areas in shale gas reservoirs, and provides technical support for the effective development of shale reservoirs on a large scale.\u003c/p\u003e","manuscriptTitle":"A Comprehensive Logging Evaluation Method for Identifying High-Quality Shale Gas Reservoirs Based on Multifractal Spectra Analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-05-23 08:31:06","doi":"10.21203/rs.3.rs-4403466/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-07-30T04:39:05+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-06-18T21:44:51+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"56699057305339408483659284091394876024","date":"2024-06-10T22:28:30+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-06-05T11:40:47+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"66754209009284426567072503929735374322","date":"2024-05-30T05:56:19+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"68069290527998161293175928251478335550","date":"2024-05-27T00:44:49+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-05-26T15:50:37+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-05-26T15:41:18+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-05-15T15:20:16+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-05-14T13:00:30+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2024-05-11T04:24:44+00:00","index":"","fulltext":""}],"status":"published","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}}],"origin":"","ownerIdentity":"b00df8a3-e7d2-4630-a783-92345070f3ae","owner":[],"postedDate":"May 23rd, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":32101870,"name":"Physical sciences/Energy science and technology/Fossil fuels/Natural gas"},{"id":32101871,"name":"Earth and environmental sciences/Solid earth sciences/Geophysics"}],"tags":[],"updatedAt":"2024-11-04T16:29:47+00:00","versionOfRecord":{"articleIdentity":"rs-4403466","link":"https://doi.org/10.1038/s41598-024-77300-1","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2024-10-30 16:20:36","publishedOnDateReadable":"October 30th, 2024"},"versionCreatedAt":"2024-05-23 08:31:06","video":"","vorDoi":"10.1038/s41598-024-77300-1","vorDoiUrl":"https://doi.org/10.1038/s41598-024-77300-1","workflowStages":[]},"version":"v1","identity":"rs-4403466","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4403466","identity":"rs-4403466","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}