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dc.contributor.advisorDavis, Thomas L. (Thomas Leonard), 1947-
dc.contributor.authorViñal, Irene
dc.contributor.committeememberBenson, Robert D.
dc.contributor.committeememberPrasad, Manika
dc.date.accessioned2007-01-03T07:11:04Z
dc.date.available2007-01-03T07:11:04Z
dc.date.issued2015
dc.description2015 Spring.
dc.descriptionIncludes illustrations (some color).
dc.descriptionIncludes bibliographical references (pages 116-118).
dc.description.abstractRecent studies have shown convincing evidence that time-lapse changes in seismic data occur not only within the reservoir interval but also in the overburden. Observations that production at the reservoir level and subsequent decrease in pore pressure lead to modifications in the stress field and variations in the overburden have been documented (Hatchell et al., 2003; Hudson et al., 2005). The study of the opposite case, that is, the analysis of the effect in the overburden of an increase in pore pressure in the reservoir has not been so well documented yet and is the focus of this work; the possibility that the hydraulic fracturing process causes seismically detectable changes in the overburden in a time-lapse sense is studied at Pouce Coupe Field, Alberta, and the results are shown. The analysis is performed using multicomponent data from three seismic surveys acquired to evaluate the hydraulic stimulations of two horizontal wells in the Montney Shale. The time-lapse time shifts between the data of the two monitor surveys and the baseline have been calculated and constitute the main tool to study the injection-induced changes above the reservoir interval. The hypothesis is that the increase in the reservoir pressure due to the hydraulic well treatment might produce upward overburden compaction, leading to an increase in stresses that would be translated into an increase in the seismic velocities and therefore, into positive time shifts (considering monitor data subtracted from baseline data) if a time window for the overburden is analyzed. The study shows strong differences in the magnitude of the PS response to the stimulations compared to that of the PP data. The fact that mode-converted (PS) waves are more sensitive to azimuthal anisotropy than compressional waves explains the stronger character of the response observed in PS data, allowing for a more detailed interpretation of the stress-arching distribution. The time-lapse time shifts in the overburden appear associated with the horizontal location of the microseismic events and with the anisotropic areas previously identified in the reservoir interval. It is also concluded that the time shifts in the overburden are much more related to the treatment of one of the wells - the best producer well, than to that of the other one. And the strongest anomalies correlate with the areas of best flow. This work shows that changes in the stress field are detectable using surface seismic data. The analysis of time shifts in the overburden is proven to be an indicator of stimulation performance, thus suggesting the potential of this technology for monitoring hydraulic fracture stimulations in unconventional reservoirs.
dc.format.mediumborn digital
dc.format.mediummasters theses
dc.identifierT 7735
dc.identifier.urihttp://hdl.handle.net/11124/17093
dc.languageEnglish
dc.publisherColorado School of Mines. Arthur Lakes Library
dc.relation.ispartof2015 - Mines Theses & Dissertations
dc.rightsCopyright of the original work is retained by the author.
dc.subjectstress
dc.subjecthydraulic fracturing
dc.subjectcross-equalization
dc.subjectoverburden
dc.subjectmulticomponent seismic
dc.subjecttime-lapse
dc.subject.lcshShale -- Alberta
dc.subject.lcshHydraulic fracturing -- Alberta
dc.subject.lcshRegolith -- Alberta
dc.subject.lcshSeismic waves -- Speed
dc.subject.lcshAnisotropy
dc.titleMulticomponent seismic monitoring of stress arching in the overburden due to hydraulic fracturing in the Montney Shale at Pouce Coupe field, Alberta, Canada
dc.typeText
thesis.degree.disciplineGeophysics
thesis.degree.grantorColorado School of Mines
thesis.degree.levelMasters
thesis.degree.nameMaster of Science (M.S.)


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