Downhole microseismic location method based on waveform stacking optimization
MAO Qinghui1,2, CHEN Junwu3, WANG Peng1, ZHONG Yu4, ZU Man5, GUI Zhixian1
1. Key Laboratory of Exploration Technologies for Oil and Gas Resources (Yangtze University), Ministry of Education, Wuhan, Hubei 430100, China; 2. Cooperative Innovation Center of Unconventional Oil and Gas (Ministry of Education & Hubei Province), Yangtze University, Wuhan, Hubei 430100, China; 3. New Resources Geophysical Exploration Division, BGP Inc., CNPC, Zhuozhou, Hebei 072751, China; 4. College of Electrical & Information Eegineering, Hubei University of Automotive Technology, Shiyan, Hubei 442002, China; 5. Exploration and Development Research Institute, PetroChina Huabei Oilfield Company, Renqiu, Hebei 062552, China
Abstract：The migration-based location technologies using waveform stacking for microseismic events have been gradually used for fracturing monitoring data processing in unconventional oil and gas reservoirs because of their advantage of not relying on the accuracy of first break picking.However, the resolution of conventional imaging functions from these technologies may be affected by a relatively low signal-to-noise ratio (SNR) to some extent.Therefore, based on previous research results, this paper improves an imaging function construction method of semblance-weighted amplitude stacking and proposes a downhole microseismic location method based on waveform stacking optimization.The proposed method can enhance the resolution of waveform stack imaging functions by multiplying the multiplication of the basic units of P- and S-wave semblance functions with that of the basic units of P- and S-wave waveform stacking functions before summing in the time window.The theoretical test results show that the improved method has better noise immunity and higher location precision compared with the conventional method.Finally, the conventional and improved methods are applied to real microseismic data acquired from one downhole monitoring well, and the effectiveness of the proposed method is verified.
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