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dc.contributor.advisorBrian J. Evans.en_US
dc.contributor.authorMighani, Saied,1989-en_US
dc.contributor.otherMassachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences.en_US
dc.date.accessioned2019-09-17T19:48:21Z
dc.date.available2019-09-17T19:48:21Z
dc.date.copyright2019en_US
dc.date.issued2019en_US
dc.identifier.urihttps://hdl.handle.net/1721.1/122224
dc.descriptionThesis: Ph. D. in Geophysics, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2019en_US
dc.descriptionCataloged from PDF version of thesis.en_US
dc.descriptionIncludes bibliographical references (pages 185-205).en_US
dc.description.abstractHydraulic fracturing is an essential tool used to enhance connectivity in shale gas reservoirs by maximizing the intersection between the hydraulic fracture (HF) and pre-existing natural fractures (NF) or faults. The technique is most effective when the hydraulic fracture crosses natural fractures rather than arresting on them. Experiments conducted to examine the interaction between HF and artificial pre-existing faults suggest that the coupling of diffusivity and fault slip is an important element of the HF-fault interaction problem. Fault slip, once activated is associated with an apparent increase in diffusivity. Whether the hydrofracture crosses or arrests on the pre-existing fault is also affected by surface roughness, differential stresses, and fault slip mode (i.e., stable or stick-slip sliding). Calibrated piezoelectric transducers were used to measure acoustic emissions (AE) generated during HF and fault slip.en_US
dc.description.abstractMoment tensor analysis of these events was used to distinguish pure tensile, shear, and possibly closure events during the experiments. Seismic moment magnitudes were approximately -7 for events during the initiation of the HF and about -5 for events during fault slip. Such a low ratio of seismic moments for tensile and slip events may explain the small numbers of tensile events recorded during reservoir stimulations. I also studied the time-dependent behavior in shales to gain insight into the post-stimulation efficiency of exploitations. Shale experiences strain hardening and compaction during loading by both isostatic (pressure-driven) and differential stress (shear-driven). Transient creep strain increased linearly with log(time), possibly transitioning to constant rate in timescale of several days. Motivated by the multi-scale nature of heterogeneities in shales, I examined the micromechanics of deformation using the nano-indentation technique.en_US
dc.description.abstractElastic and creep moduli found in nano-indentation and triaxial tests agreed within a factor of 2, but within that factor, the creep strength may depend on spatial scale.en_US
dc.description.statementofresponsibilityby Saied Mighani.en_US
dc.format.extent205 pagesen_US
dc.language.isoengen_US
dc.publisherMassachusetts Institute of Technologyen_US
dc.rightsMIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.en_US
dc.rights.urihttp://dspace.mit.edu/handle/1721.1/7582en_US
dc.subjectEarth, Atmospheric, and Planetary Sciences.en_US
dc.titleSome rock mechanics problems with application for hydraulic fracturingen_US
dc.typeThesisen_US
dc.description.degreePh. D. in Geophysicsen_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciencesen_US
dc.identifier.oclc1119388726en_US
dc.description.collectionPh.D.inGeophysics Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciencesen_US
dspace.imported2019-09-17T19:48:19Zen_US
mit.thesis.degreeDoctoralen_US
mit.thesis.departmentEAPSen_US


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