MICROSEISMIC MONITORING: PHYSICAL MODELING AND SOURCE CHARACTERIZATION

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dc.contributor.advisorStewart, Robert R.
dc.contributor.committeeMemberZhou, Hua-Wei
dc.contributor.committeeMemberAy, Erkan
dc.creatorAkbas, Omer 1987-
dc.date.accessioned2014-02-13T15:25:45Z
dc.date.available2014-02-13T15:25:45Z
dc.date.createdDecember 2013
dc.date.issued2013-12
dc.date.updated2014-02-13T15:25:50Z
dc.description.abstractThis research investigates some fundamental aspects of microseismic monitoring: location and source mechanism. We developed a ray-tracing and diffraction-stack procedure to determine source locations. The location algorithm uses a grid-search technique to find source coordinates. For every possible point source, three attributes (traveltime residual, stacked energy and energy/residual ratio) in a grid area are calculated. Then the location can be found by either choosing the point that yields a minimum traveltime residual or maximum stacked energy or maximum energy/traveltime ratio. Further, focal mechanisms and radiation patterns of simulated microseismic events are examined using Focmec (Focal Mechanism Determination), an open-source program. The location algorithm is developed in a MATLAB environment and tested on physical modeling data from the Allied Geophysical Laboratories (AGL) at the University of Houston. Three different physical modeling experiments have been conducted using ultrasonic source and 3-component receivers. For the first experiment, a single layer Plexiglas model was used; the second experimental model was built by assembling Plexiglas and aluminum blocks. In the third experiment, a real sandstone rock (57.5 x 43.8 x 17.5 cm) was employed. To determine which method (P versus S waves and travel time versus amplitude) and acquisition design (surface or borehole receivers) is most accurate, we have undertaken variety of tests. Locating events using S-waves is as accurate as with P-waves; however, combining both P and S-waves are the most accurate approach among all experiments. Furthermore, location certainty increases when downhole receivers are included for both P and S-waves. To increase the speed of the algorithm, CPU and GPU computing was implemented. Locating a single microseismic event with 7 different methods takes 11.4 seconds on single core CPU, whereas, this number is decreased to 4.2 seconds using multi-core CPU computing. Further, implementing GPU computing further decreases the total elapsed time to only 1.9 seconds. There is more than an 80 percent increase in terms of computation time compared to single core CPU.
dc.description.departmentEarth and Atmospheric Sciences, Department of
dc.format.digitalOriginborn digital
dc.format.mimetypeapplication/pdf
dc.identifier.urihttp://hdl.handle.net/10657/524
dc.language.isoeng
dc.rightsThe author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).
dc.subjectMicroseismic
dc.subjectLocation
dc.subjectHydraulic fractures
dc.subjectFocal mechanisms
dc.subjectGPU
dc.subjectCpu
dc.subjectComputation time
dc.subjectParallel computing
dc.subjectGPU computing
dc.subjectRay tracing
dc.subjectMigration type location
dc.subjectAmplitude/traveltime ratio
dc.subjectRadiation patterns
dc.subjectP-wave
dc.subjectS-wave
dc.subjectPhysical modeling
dc.subjectUltrasonic
dc.subject.lcshGeophysics
dc.titleMICROSEISMIC MONITORING: PHYSICAL MODELING AND SOURCE CHARACTERIZATION
dc.type.dcmiText
dc.type.genreThesis
thesis.degree.collegeCollege of Natural Sciences and Mathematics
thesis.degree.departmentEarth and Atmospheric Sciences, Department of
thesis.degree.disciplineGeophysics
thesis.degree.grantorUniversity of Houston
thesis.degree.levelMasters
thesis.degree.nameMaster of Science

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