Research On Micro-seismic Ground Monitoring And Location Technology Based On Grid Division

Hydraulic fracturing has been widely used in recent years,in the dense oil and gas in the hydraulic fracturing of rock cracks can significantly improve the density of the permeability of the rock,so as to improve the capacity of unconventional oil and gas.Micro-seismic monitoring technology can effectively monitor the underground rock fracture and seismic activity induced by hydraulic fracturing,and provide real-time guidance for hydraulic fracturing.The effectiveness of the microseismic monitoring is the key to real-time monitoring of fracturing construction,namely at the same time of fracturing operation using microseismic monitoring technology in real time to describe the crack growth under,in a timely manner for the fracturing construction to make evaluation and correction parameter,finally to ensure the effect of fracturing operation.Therefore,it is one of the important tasks of microseismic monitoring to make rapid and accurate localization of microseismic events.Grid search class positioning algorithm is don't need to pick up early to signal,but also introduced the advantages of more elaborate velocity model,this method can largely offset due to the earthquake SNR microseismic monitoring ground caused by the defects,and improve the micro seismic positioning credibility.So this article on the basis of grid search positioning method,in order to improve the micro seismic positioning accuracy and speed,for the purpose of the microseismic location in the forward process,correction method for velocity model and inverse positioning methods were studied.Method in numerical simulation is,in this paper,the ray tracing piecewise iteration method is used to calculate flexibility,high computational efficiency,and the advantage of high precision,analyzes the piecewise iteration method of ray tracing study,applied to the 2 d and 3 d grid structure,and according to the model trial at the beginning of the method to get to the data and the actual shot early to compare data,provide the basis for subsequent source localization.In terms of speed of inversion model correction,after correction of velocity model based on single perforation,perforation point far in distance to locate microseismic events can cause larger error of this defect,on the basis of amplitude superposition proposed a focal position and velocity model of the joint inversion method,this method using the initial positioning of the source location to make up for the speed of the blind area caused by perforating shortage,source location and velocity model for joint correction parameters at the same time,to the global correction velocity model.In terms of micro seismic events inversion positioning,based on the grid of successive subdivision localization algorithm on the basis of the successive subdivision localization algorithm for grid orientation disorder problems in dealing with a high frequency signal,this paper proposes a successive based on fast simulated annealing algorithm and the grid subdivision algorithm,replace the fast simulated annealing grid subdivision for the first time in the successive subdivision algorithm process,avoid the grid center cannot fall into the situation of envelope area,thus located in circumstances to improve the speed of computing the reliability.In the end,this paper makes a practical treatment of a hydraulic fracturing micro-seismic monitoring data of 1X well in Langfang area of Hebei province to verify the practicability of this method.According to the results of micro seismic monitoring and geometric parameters of cracks in the explanation and evaluation of hydraulic fracturing effect,the test results are consistent with local geological structure,prove the feasibility of the method in actual fracturing monitoring.