Research Of Events Detection And Source Location Method For M Icroseismic Monitoring

Microseismic monitoring technology is a very important technology to conduct the development and fracturing of oil and gas field by monitoring and analysis production activities effects and influences due to microsesmic events becauses of production.At present,the domestic situation is middle and high permeability oil and gas fields in the development are fewer and fewer,and more and more low permeability oil and gas fields are in development.A large number of untapped reserves are concentrated in the low permeability reservoir.Therefore,in the process of the development of our petroleum industry,the low permeability oil field plays a more and more important role in oilfield development.Microseismic monitoring has proven to be a highly efficient and rapid solution.With the development of the acoustic monitoring technique,micro seismic monitoring technology began to rise.Microseismic monitoring does not use traditional seismic wave produced by artificial source,but use seismic waves produced by conventional water injection or hydraulic fracturing and so on.With the development of microseismic monitoring technology theory,microseismic monitoring technology is playing an increasingly important role in the exploration and research of cracks caused by hydraulic fracturing.At present,the applications of the microseismic monitoring technology in the fields are as follows:monitoring reservoir fracturing to obtain fraturing parameters such as the scope of fracture and fracture development direction,and evaluating fracturing effect objectively to effectively guide the further oil and gas field development;Dynamic monitoring reservoir fluid pressure on the leading edge and assisting engineers to develop the adjustment and optimization of design scheme;Providing information of internal deformation mechanism and fracture morphology,fracture reservoir and so on.In this paper by the research on the basis of micro seismic signal characteristics,combined with the thought of earthquake P arrival picking-up,especially for low SN microseismic signal,study a picking-up method suitable for microseismic signal characteristic.Synthetic microseismic signal and actual data tests that it can effectively pick up first arrival of microseismic singal with low SN.In addition,microseismic signals with low signal noise ratio(SNR)bring difficulties to pick up microseismic signals first arrival extractly.This paper have a research on a microseismic time-difference location algorithm based on nonlinear inversion algorithm combined with ray tracing theory by analysizing factors effecting microseismic signal first arrival.In order to further avoid positioning accuracy reducing caused by the microseismic first arrival picking errors,study a microseismic source localization algorithm based on the theory of the time-reverse source location.This method can effectively avoid the reduction of source location precision due to picking up errors because of microseimic signal with low SNR.Model testl and the actual data are further validated the method proposed in this paper.