Research On Data Processing And Imaging Technology Of Joint Seismic-electrical Monitoring

With the development of science and technology and the globalization of economy,the demand for oil is increasing year by year.The conventional oil and gas resources have been exhausted in the process of exploitation for decades,which can not meet the needs of human life today.Therefore,it is urgent to improve the oil and gas recovery.More and more attention has been paid to the exploitation of unconventional oil and gas resources in China.The hydraulic fracturing technology has become a powerful technical support to guide the exploitation of unconventional oil and gas fields.And the imaging result of fracturing fractures is an important index to evaluate hydraulic fracturing.The current hydraulic fracturing methods are mainly based on single geophysical exploration,such as micro-seismic monitoring and borehole-surface electrical monitoring.However,the single monitoring methods have limitations and multiple solutions on a certain degree.The micro-seismic method is often difficult to obtain the accurate monitoring results when there is much interference during hydraulic fracturing.Furthermore,during the monitoring of low-resistivity reservoir fractures by borehole-surface electrical monitoring,the monitoring results cannot reach the ideal state due to the small difference in resistivity between reservoir and fracturing fluid.In order to solve the limitation and multiple solution of single geophysical exploration method,according to the development trend of hydraulic fracturing monitoring at home and abroad,this paper summarizes the basic principle of micro-seismic monitoring and borehole-surface electrical monitoring,puts forward a method of joint seismic-electrical monitoring,and designs an efficient method of joint seismic-electrical field exploration.This method can make up for the shortcomings of the single method,and successfully achieve accurate monitoring of fracturing fractures.The numerical simulation analysis process of micro-seismic monitoring and borehole-surface electrical monitoring is realized by using the finite differencemethod of variable staggered grid and the three-dimensional finite difference method respectively,which provides a reliable theoretical basis for the joint seismic-electrical monitoring.Joint seismic-electrical monitoring method uses a set of instruments to realize the measurement of two kinds of monitoring data,summarizes the characteristics of the collected micro-seismic signal and borehole-surface electrical signal,designs the signal preprocessing process according to the actual needs of the data itself,and displays the final fractures by using overlapping of seismic amplitude and the change of resistivity difference of the electrical data technology.At present,the system has been successfully tested in Liaohe Oilfield.The results show that the specific direction of the crack is the east-west wing,and the length of the crack is roughly symmetrical,with a total length of 110-160 meters and a north eastward orientation of 85 degrees.The results are compared with the geological structure of the monitoring area and the basic parameters of the fracturing well,indicating that the final imaging results are accurate.