井中微震监测数据处理方法研究与应用

Study and Application of Well Microseismic Monitoring Data Processing Methods

井中微震监测的目的是确定压裂过程产生的裂缝的几何形态,采集到具有微震事件的原始记录信噪比低,纵横波初至拾取困难,直接影响到微震的定位及后续的裂缝形态描述。通过分析但由于微震信息较弱,因此微震事件的记录特点,结合实际应用过程中遇到的问题对处理方法进行了研究,包括去噪处理、微震事件识别、纵横波初至拾取、极化分析、模型建立及校正、微震定位等。研究表明,带通滤波可有效法除噪音;长、短时窗能量比法可精确的记录微震事件及初至时间自动拾取;利用纵波尖端曲线图可以确定微震源方向;速度模型的建立应以校正炮时距曲线拟合理论曲线为原则;利用Geiger和网格搜索法可精确得到震源定位结果。

The aim of well miernseismie monitoring is to determine geometry of fissures produced during the fracturing proeess, since the low S/N ratio of acquired original recoM with mieroseismic events, thus difficult to pick up P-wave and S-wave firs/arviwds, direct- ly impact microseismie positioning and succeeding fissure configuration describing. Because of rather weak mieroseismie information and mieroseismic recording peculiarity, as well as issues encountered during practical application process, carried out studies .n pro- eessing methods including de-nnising, mieroseismie event identification, P-wave and S-wave firsl arrivals pickup, analysis of polariza- tion. modeling and correction, mieroseismie posilioning etc. The study has showm the band-pass filtering can effectively remove noises long and short time windows energy ratio method can precisely record microseismic event and first arrival time automatic pickup; using P-wave tip curve can determine mieroseismic source direction; velocity modeling should take corrected shot time-distance curve fit- ting theoretical curve as principle; using Geiger and grid searching method can get precise source positioning results.