青海狮子沟油田天然微地震活动及其地质意义

通过对柴达木盆地西部狮子沟地区一年多的微地震监测数据的分析处理,发现该区微地震活动比较频繁,总体走向北西,且多集中在该区盆山过渡带北西走向的花土沟断裂北东侧2km深度附近。通过对地震与钻孔分布之间的关系和地震发生频次对数与震级线性关系的斜率b值的分析,本文认为,虽然油井注水等因素对研究区内微地震事件具有一定的诱发作用,但大部分地震事件仍主要与断裂及其次级构造有关。

MICRO-EARTHQUAKES IN THE SHIZIGOU OILFIELD, QINGHAI, AND THEIR GEOLOGICAL SIGNIFICANCE

A large number of high-quality seismic data are recorded in the Shizigou oilfield of the western Qaidam basin by monitoring micro-earthquakes for more than one year.After processing and analyzing these data, the authors find that micro-earthquakes occur relatively frequently in the study area and are mainly concentrated at ~2 km depth on the NE side of the NW-trending Huatugou fault in the basinmountain transition zone of the area.Analyses of the relation between earthquakes and oil well distribution and the slope b in the linear relation between log frequency and magnitude show that microearthquakes in the study area are mainly related to the Huatugou fault and its secondary structures though fluid injection through the wells has a certain microearthquake-inducing effect in the area.