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任邱地区历史上地震少而弱。1976年12月油田开始注水,注水前无微震记录,注水后三个月即有地震发生,随注水量增加,地震活动增强,地震活动特点是:注水量二阶差分Δ~2y_i(正值)较高后一至三个月有地震发生;Δ~2y_i大小与地震强度相关;震中分布受注水井位置控制;地震序例b位为0.65;单台初动符号及振幅比比较一致。初步研究认为:本区岩石为多孔隙岩石,断裂较多,注水使孔隙压力增大,降低了断层面上的摩擦阻力,积累的应力便以地震形式释放。
Renqiu area history of the earthquake is small and weak. There was no microseismic record before the injection in December 1976. There was an earthquake three months after the water flooding. With the increase of water injection, the seismic activity was enhanced. The seismic activity was characterized by the second-order difference of water injection Δ 2y_i (positive value) The earthquakes occurred one to three months later, the magnitude of Δ2y_i was related to the earthquake intensity, the epicenter distribution was controlled by the location of the injection well, and the b-sequence of earthquakes was 0.65. Preliminary studies suggest that: the rock in this area is porous rock with more fractures, water injection increases the pore pressure, reduces the frictional resistance on the fault plane, and the accumulated stress is released as an earthquake.