Research On Denoising Method Of Ground Microseismic Data

With the continuous exploration and development of unconventional oil and gas,the demand for microseismic monitoring technology is more and more intense.The exploration and development of unconventional oil and gas requires hydraulic fracturing,and microseismic is an important method to evaluate the fracturing effect.Therefore,in the research of unconventional oil and gas,microseismic monitoring is one of the most important technologies.The main function of microseismic data is to analyze the reconstruction area?reconstruction effect and underground state of fracturing based on the microseismic events produced in hydraulic fracturing production,and to analyze and evaluate the fracturing effect.There are two kinds of microseismic monitoring methods: monitors in the well and monitors on the surface.The monitoring mode depends on the working conditions of fractured wells,structural location and the situation of surrounding wells.Compared with borehole microseismic monitoring,ground microseismic monitoring has the advantages of no need of monitoring well,flexible wiring and low wood forming.However,when monitors in the ground,the seismic wave travel path is long and the signal attenuation is huge.In addition,the noise type of the microseismic data is complex,and the overall signal-to-noise ratio of the microseismic data is lower,which brings great difficulties to the subsequent first break picking and inversion positioning,so the research and application of noise suppression method is the key link of surface microseismic data processing.In this paper,the noise types of microseismic data and different noise suppression methods are systematically investigated and analyzed.The kinematic and dynamic characteristics of effective signal and noise interference in microseismic data are deeply understood.In view of the industrial interference and drilling interference in the actual microseismic data,the iterative cross-correlation and Wiener filtering method are proposed to remove the single frequency interference noise.This paper solves the problems existing in conventional methods such as notch frequency and frequency domain suppression.By simulating single frequency noise and subtracting it,noise suppression technology realizes effective signal protection.Aiming at the data before micro seismic fracturing monitoring and background noise,the maximum eigenvalue is obtained from the background noise,and the contribution of each singular value component to the data reconstruction is accurately judged by combining the singular value reduction ratio before and after,It is applied to the selection of characteristic value of microseismic monitoring data,and then the suppression calculation of microseismic noise is completed.Through the processingof theoretical model data and actual data,it is shown that the joint denoising method based on various methods can make up for the shortcomings of different methods in the processing of microseismic data,effectively suppress the random noise in the data,and the noise suppression effect is obvious,which provides a good basis for the correct identification of microseismic events and the accurate positioning of the source.