Geomechanics of Microseismic Deformation
Microseismic sources and emission of the detected seismic waves are an expression of some aspects of the complete geomechanical deformation of the hydraulic-fracture network. Specific signal attributes can be analyzed to estimate source characteristics of the episode of coseismic fracture deformation that corresponds to generation of the microseismic source. Amplitude characteristics of the seismic signal are related to the source strength or magnitude of the microseismic event. Frequency content can be related to the slip duration and hence the source radius or slip area. Other aspects such as stress release and energy flux also can be estimated. Finally, the directivity or radiation pattern of the relative amplitudes and first motion can be used to investigate the microseismic source mechanism, including mode of fracturing (i.e., tensile opening or shear deformation), fracture-plane orientation, and principle stresses leading to the failure.
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Microseismic Imaging of Hydraulic Fracturing: Improved Engineering of Unconventional Shale Reservoirs
Microseismic monitoring is the key technology to image hydraulic fractures. With the recent industry focus on unconventional resources and the associated need for effective hydraulic fracture treatments to stimulate flow, microseismic monitoring has become a commonplace technology in the geophysical community. Microseismic has long been a niche geophysical technology to image fracturing, but the expansion of the technology over the last decade is evident by the increasing number of workshops, papers in various publications, and the sheer number of papers and associated dedicated sessions at the SEG annual meeting. This work aims to provide a practical user guide for survey design, quality control, interpretation, and application of microseismic hydraulic fracture monitoring. The book is intended to provide a comprehensive educational resource for microseismic hydraulic fracture imaging, with a focus on practical tips for executing a successful microseismic project. Limitations of the data and potential pitfalls are emphasized throughout.