From Static Design to Dynamic Safety: Well Control–Based Casing Depth Optimization in Niger Delta Wells

From Static Design to Dynamic Safety: Well Control–Based Casing Depth Optimization in Niger Delta Wells | 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 From Static Design to Dynamic Safety: Well Control–Based Casing Depth Optimization in Niger Delta Wells Chukwudi Ohaegbulam, Kevin Igwilo, Anthony Chikwe, Ifeanyichukwu Onyejekwe, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8497719/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Well design in oil and gas drilling is traditionally performed under static pore–fracture pressure constraints, often neglecting dynamic well control behavior during kick circulation. This limitation is particularly critical in narrow pore–fracture margin environments, where small influxes can rapidly escalate into underground blowouts. This study develops a pressure-balance-based well control model that integrates maximum allowable annular surface pressure (MAASP) and maximum allowable kick volume (MAAKV) into casing depth optimization. The methodology is demonstrated using real subsurface pressure profiles, gas kick properties, and well configuration data from two offshore Niger Delta wells. Base-case casing programs were re-evaluated under dynamic circulation conditions and compared with optimized designs incorporating under-reaming in critical narrow-margin sections. Results show that MAAKV decreases sharply with depth, reaching critically low values (< 12 bbl in Well A and 26 bbl in Well B) in deep intervals, indicating that small kicks may escape detection and cannot be safely circulated without fracturing the formation at the casing shoe. Introducing under-reaming increased kick tolerance by up to 342% in Well A and 96% in Well B, substantially expanding the safe operating envelope. The proposed approach enhances well control safety, reduces underground blowout risk, and offers economic benefits through optimized casing placement. Physical sciences/Engineering/Mechanical engineering Physical sciences/Energy science and technology/Energy modelling Well control modeling Casing depth optimization Kick tolerance Maximum allowable kick volume Driller’s Method Under-reaming Narrow pore–fracture margin Niger Delta Annular surface pressure Drilling safety Full Text Additional Declarations There is NO Competing Interest. Cite Share Download PDF Status: Under Review 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-8497719","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":575719807,"identity":"8a3c55a3-6a76-4b2d-832a-ad11eceb218c","order_by":0,"name":"Chukwudi 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Wells","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Well control modeling, Casing depth optimization, Kick tolerance, Maximum allowable kick volume, Driller’s Method, 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This limitation is particularly critical in narrow pore\u0026ndash;fracture margin environments, where small influxes can rapidly escalate into underground blowouts. This study develops a pressure-balance-based well control model that integrates maximum allowable annular surface pressure (MAASP) and maximum allowable kick volume (MAAKV) into casing depth optimization. The methodology is demonstrated using real subsurface pressure profiles, gas kick properties, and well configuration data from two offshore Niger Delta wells. Base-case casing programs were re-evaluated under dynamic circulation conditions and compared with optimized designs incorporating under-reaming in critical narrow-margin sections. Results show that MAAKV decreases sharply with depth, reaching critically low values (\u0026lt;\u0026thinsp;12 bbl in Well A and 26 bbl in Well B) in deep intervals, indicating that small kicks may escape detection and cannot be safely circulated without fracturing the formation at the casing shoe. Introducing under-reaming increased kick tolerance by up to 342% in Well A and 96% in Well B, substantially expanding the safe operating envelope. The proposed approach enhances well control safety, reduces underground blowout risk, and offers economic benefits through optimized casing placement.\u003c/p\u003e","manuscriptTitle":"From Static Design to Dynamic Safety: Well Control–Based Casing Depth Optimization in Niger Delta Wells","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-20 03:23:44","doi":"10.21203/rs.3.rs-8497719/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"communications-engineering","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"commseng","sideBox":"Learn more about [Communications Engineering](http://link.springer.com/journal/44172)","snPcode":"44172","submissionUrl":"https://mts-commseng.nature.com/cgi-bin/main.plex","title":"Communications Engineering","twitterHandle":"@commseng","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"b6486a62-5553-4024-8cc1-620ead89bebf","owner":[],"postedDate":"January 20th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":61261110,"name":"Physical sciences/Engineering/Mechanical engineering"},{"id":61261111,"name":"Physical sciences/Energy science and technology/Energy modelling"}],"tags":[],"updatedAt":"2026-04-21T15:06:05+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-20 03:23:44","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8497719","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8497719","identity":"rs-8497719","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}