Passive seismic full waveform inversion with unknown onsets in an orthorhombic anisotropic medium
KAUST DepartmentEarth Science and Engineering Program
Physical Science and Engineering (PSE) Division
Seismic Wave Analysis Group
Permanent link to this recordhttp://hdl.handle.net/10754/661891
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AbstractFull waveform inversion (FWI) based methods are getting more attractive in passive seismic (microseismic) monitoring studies. A high resolution knowledge of the medium in which the events occur is crucial to proper monitoring. In most cases, not only the velocity, but also the anisotropy has a large influence on locating passive events related to hydraulic fracturing. Due to the inherent anisotropy nature of most rocks associated with unconventional reservoirs, accounting for anisotropy is even more important in such investigations. We propose a 3D acoustic orthorhombic FWI method for passive seismic events to invert for the source image, source function and the model parameters, without any a prior knowledge about source location or source function in time. In order to mitigate the effect of the unknown source ignition time, we convolve reference traces with the observed and modeled data. A total variation regularization is applied to improve the robustness of the model parameters inversion considering the limited sources and illumination angles of microseismic experiments. The adjoint-state method is used to derive the gradient for the source image, source function and the anisotropic model parameters. The proposed method produces good estimates of the source location and the model structures for the modified orthorhombic 3D SEG/EAGE overthrust model.
CitationWang, H., & Alkhalifah, T. (2019). Passive seismic full waveform inversion with unknown onsets in an orthorhombic anisotropic medium. SEG Technical Program Expanded Abstracts 2019. doi:10.1190/segam2019-3214356.1
SponsorsWe thank KASUT and KAUST Supercomputing Lab for supporting to this research. We thank SWAG members for their helpful discussion. We specially thank Dr. Nabil Masmoudi for his help in the orthorhombic inversion and the codes.
PublisherSociety of Exploration Geophysicists
Conference/Event nameSociety of Exploration Geophysicists International Exposition and Annual Meeting 2019, SEG 2019