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dc.contributor.advisorTutuncu, Azra
dc.contributor.authorPermata, Ilham
dc.date.accessioned2019-07-08T21:07:38Z
dc.date.accessioned2022-02-03T13:16:07Z
dc.date.available2019-07-08T21:07:38Z
dc.date.available2022-02-03T13:16:07Z
dc.date.issued2019
dc.identifierPermata_mines_0052N_11757.pdf
dc.identifierT 8747
dc.identifier.urihttps://hdl.handle.net/11124/173092
dc.descriptionIncludes bibliographical references.
dc.description2019 Summer.
dc.description.abstractA conceptual model of the Newberry EGS (Enhanced Geothermal System) project stimulation program for well NWG 55-29 has been developed. A discrete fracture network (DFN) model is embedded in the simulation to investigate effect of in situ stress state and natural fractures or faults properties. The local in situ stress information has been revisited and a new interpretation is proposed. Simulation results using the conceptual model are compared to a case of previously published stress information. To revisit the stress determination, compressive failure around a wellbore has been analyzed and different modes of breakouts were distinguished. Incorporating temperature change, a simple compressive failure model based on Mohr-Coulomb failure criterion for inclined wellbores has been developed. The model has been first used to perceive compressive failure profile when breakouts and tensile wall fractures simultaneously occurred at a wellbore from a well at Visund Field in the North Sea. The model illustrates distinct profiles at the direction of breakouts and tensile wall fractures. Further, it is also applied to well GPK2 at the Soultz geothermal field in France, where thermally induced or mode-X breakout has been observed. Different modes of compressive wellbore failure are observed, B-mode for conventional breakout and X-mode for breakout at the opposite side as compressive failure happening due to small tensile cracks. This distinct profile was then used to analyze the compressive failure profile for the NWG 55-29 well in Newberry EGS. Eventually, mode-X breakout is observed, indicating the direction of maximum horizontal stress, instead of minimum horizontal stress as previously studied. This finding is consistent with image log observation of nearby well and regional shear wave evaluation. The simulation is conducted using CFRAC simulator. Based on microseismic distribution and bottomhole pressure data, the simulation case with current stress determination is more consistent. It is also suggested that hydroshearing is not enough to enhance permeability in not-well-oriented natural fracture distribution. Though this is not a desired case for thermal extraction, better permeability enhancement could be achieved by injection pressure higher than the minimum horizontal stress. This study demonstrated that the simple failure model could be utilized in accordance with breakout observations and how prior stress determination and fracture characterization could significantly affect stimulation design and reservoir development strategy.
dc.format.mediumborn digital
dc.format.mediummasters theses
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado School of Mines. Arthur Lakes Library
dc.rightsCopyright of the original work is retained by the author.
dc.subjectEGS
dc.subjectgeothermal
dc.subjectthermally-induced breakout
dc.subjectfailure model
dc.subjectbreakout
dc.subjectNewberry EGS
dc.titleEnhanced geothermal system (EGS) well stimulation design and simulation using DFN-based model: Newberry EGS case study
dc.typeText
dc.contributor.committeememberMiskimins, Jennifer L.
dc.contributor.committeememberWu, Yu-Shu
thesis.degree.nameMaster of Science (M.S.)
thesis.degree.levelMasters
thesis.degree.disciplinePetroleum Engineering
thesis.degree.grantorColorado School of Mines


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