Inversion Location Research Of Surface Micro-seismic Event

Surface microseismic monitoring technology, compared with wellbore microseismic monitoring,will be widely technology in the field of micro-seismic fracturing monitoring, its application prospects will be great. It can implement the fracture monitoring and real-time monitoring of reservoirs after water injection and gas injection, which is meaningful to exploration and development of reservoirs. The core of micro-seismic monitoring technology is the exact location of micro-seismic events. In this paper, we have researched the forward modeling, the inversion algorithms and seismic phase identification and inversion of micro-seismic events, and realized the high precision inversion and location of surface micro-seismic source.According to the characteristics of surface micro-seismic monitoring, discussed ray tracing using the optimization method in bending interface,horizontal layer interface and tilt layer interface three model.after the discussion of advantage and disadvantage of shooting method, iterative method and bending method, we have researched the iterative ray tracing method of tilt layered medium significantly, and realized the forward modeling of transmission, reflection, refraction in tilt layered models. In the horizontally layered medium, comparison between forward result of shooting method and that of iterative method has proved that this method is right and has high precision and efficiency.Combined with real surface micro-seismic signals, on the basis of discussion about the inversion precision and applicability of simplex replace method, differential evolution methodin micro-seismic inversion problems, we propose the joint inversion of tBased on the simplex replace differential evolution hybrid inversion algorithm according to the advantages of these methods, better to improve the convergence inversion process and better to avoid the inversion solution for the local optimal solution of the problem and make the inversion more stability and reliable.To the actual material of surface, microseismic event location,by establishing appropriate observation system, set up by well logging data speed model, and then the perforating material and strong events to calibrate initial velocity model.Finally to the surface microseismic event inversion positioning.Combining event development characteristics, characteristics of gather and fracturing area on the ground the structural characteristics of the micro earthquake events explanation.And with the United States, the monitoring of the microseismic company and comparing with the results of the reliability analysis of crack orientation, so as to verify the ground of a complete set of micro seismic inversion the feasibility of the method.