Micro-seismic Event Location With Reverse Time Migration

The production and safety of underground exploration areas,such as the monitoring of hydraulic fracturing in tight oil reservoirs and the monitoring of rock burst and ground pressure impact in mines,are inseparable from the extensive application of micro-seismic monitoring technology.Through micro-seismic monitoring,the micro-seismic activity in the underground exploration area can be fed back in real time,fracturing effect can be monitored,and the occurrence of mine earthquakes can be prevented and controlled.Traditional microseismic monitoring can not meet the needs of modern microseismic monitoring in microseismic fine imaging,fracture dynamic monitoring and underground stress inversion.P-wave and S-wave and well-site joint monitoring technology emerged.The combined technology of vertical and horizontal wave Wells and ground breaks through the traditional seismic monitoring,and has the advantages of high positioning accuracy,high imaging point energy and convenient calculation.In this paper,the method of combining p-wave and s-wave with borehole location is presented,which not only optimizes the calculation speed,but also gives consideration to the location accuracy.The main content of this paper is to study the passive source event of inverse time offset location.There is an analytical solution to the inverse time migration of P-wave and S-wave,which can be used to locate accurately.The vertical resolution of in-well monitoring is higher than that of ground monitoring,and the ground observation has high horizontal resolution thanks to the advantages of low cost,wide range and diverse combinations of geophone layout.Therefore,adopt the method of shaft joint of p-wave,can get better resolution,on the depth compared with the single way of monitoring can be extracted effectively micro seismic events,while doing well to joint monitoring can change the position of the ground observation arrays,increasing horizontal underground observation Angle of view,compared with the monitoring well greatly reduces the construction cost and complexity.