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dc.contributor.authorWang, Kai
dc.date.accessioned2018-07-26T00:15:22Z
dc.date.available2018-07-26T00:15:22Z
dc.date.issued2015-07
dc.identifier.urihttp://hdl.handle.net/11122/8866
dc.descriptionMaster's Project (M.S.) University of Alaska Fairbanks, 2015en_US
dc.description.abstractPermafrost underlies approximately 80% of Alaska. Permafrost's high sensitivity to temperature variations plays a significant role in the stability of wellbores drilled through permafrost formations. Wellbore instability may cause stuck pipes, lost circulation, and/or collapse of the wellbore, resulting in extra cost and time loss. In order to minimize the influence of the heat produced during drilling, a vertical well is the only choice to penetrate permafrost formation. Fast Lagrangian Analysis of Continua (FLAC) was used in this simulation to test the minimum wellbore pressure to maintain stability in a permafrost formation. Three layers were set in the simulation model: clay, silt, and sand. With the drilling fluid temperature set at 343K and a 267K initial formation temperature, four different thermal times, i.e. 1 week, 1 month, 1 year, and 5 years, were tested to determine the minimum stable pressure. Pore pressure of the formation has the strongest effect on this pressure. And in a short operation period, drilling fluid temperature will not influence the minimum mud pressure value significantly. A regression analysis was conducted on the simulation results, and the minimum wellbore stable pressure was found to be a function of pore pressure, cohesion, frictional angle, temperature difference, conductivity difference, thermal time, and wellbore radius. With the help of this function, engineers could calculate stable pressure for wells in arctic area before drilling based on drilling fluid temperature.en_US
dc.language.isoen_USen_US
dc.subjectOil well drillingen_US
dc.subjectStabilityen_US
dc.subjectArctic regionsen_US
dc.subjectCold regionsen_US
dc.subjectPermafrosten_US
dc.subjectDrilling mudsen_US
dc.titleSimulation and analysis of wellbore stability in permafrost formation with FLACen_US
dc.typeMaster's Projecten_US
dc.type.degreems
dc.identifier.departmentPetroleum Engineering Department
dc.contributor.chairPatil, Shirish
dc.contributor.chairChen, Gang
refterms.dateFOA2020-03-05T16:30:34Z


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