Automatic Detection And Location Of Microseismic Events

Microseismic monitoring is a technique applied to the reservoir dynamic monitoring by detecting and analysising the microseismic singnals of rock bed crack or faulting caused by hydraulic fracturing or oil, gas extraction. Which is widely used domestic at present is hydraulic fracture monitoring, image the fluid front of water injecting, analysis the result of fracture, in order to guide field production, and provide the basis for adjust of reservoir engineering.The result and evaluation of hydraulic fracture is needed in the adjusting of the development program , so real-time processing of hydraulic fracture microseismic monitoring is needed. For this purporse, this article research the method of detection of microseismic events and location of microseismic sources.This thesis introduce the preprocessing technique to the data of microseismic monitoring firstly, to overcome that the normal filting techbique can not be useful in microseimic data processing, analysis the polarization filter if both time domain and frequency domain, use the multi-taper function decision the multi-taper polarization filter in frequency, this filter could obtain ideal effect in the data of low signal-noise ratio. Then analysis the characters of microseismic singals and noise in the borehole envirenment, decision the method based on energy ratio with different windows combined with polariztion anylysis, the regularity among different geophones are bring in to constrain the detection results.To avoid the infect of firstbreaking in the prosessing of microseismic monitoring data, the method using signal stacking scanning the space to locate the microseismic sources is designed. While discussing the criterion of stacking in space scan, the tracking component is involved to make a full use the energy information of three components.The reliability of the space scanning method is tested with the models and real monitoring date.Then, the constrution technique of hydraulic fracture microseismic mornitoring is recommended, and design the package workflow of microseismic data processing, which is used to process the real data and give the location of the injection fracture, verfication the location results through some other information.At the last of the paper, according the time the fracture emerging and the relative energy of the sources, combining the geology data ,analysis the injection water front and the distribution of hydraulic fracture.Testfied by models and real monitoring data, the methed of automatic detection and location can realize the real time monitoring of hydraulic fracure microseismic monitoring.