摘要
1985年12月至1986年1月发生的山东省胜利油田角07井注水地震序列,经历了特有的演化过程,即全序列可分解为4个子序列,且子序列逐渐由震群型向主余型过渡.前期地震(最大地震之前)呈升级趋势,地震b值前期高于后期,地震时间结构的分数维D则前期低于后期,以及较大地震的lg△t-lgt前期较为紊乱,而后期线性相关等.计算表明,注水后岩石孔隙压力大于临界孔隙压力,从而诱发了地壳浅部岩石低初始应力的提前释放,而水的渗透作用则导致岩石孔隙压力随时间由高度非均匀分布向相对均匀分布转换.角07井地震序列的演化与这一物理过程有关.
The earthquake sequences,occurring from December 1985 to January 1986,induced by water injection into Jiao 7 oil well of Shengli oil field,Shandong Province. The earthquakes have undergone a particular evolutional process,the whole sequence can be divided into four sub-sequences,and the sub-sequence transiting gradually from the earthquake swarm type to the main shock-after shock type; the early earthquakes occurring before the largest earthquake showing a tendency of increase in magnitude,the earthquake &-value being higher in the early period than in the late period,the fractal dimension,D.,of the time composition of earthquakes being lower in the early period than the in late period. The lg(At) -lg(t) of the major earthquakes being more disorderly in the early period,and showing linear dependence in the late period. The pore pressure is larger than the critical pore pressure in the rock after water injection and therefore inducing premature release of the initial stress existing in the rock of shallow crust,but the osmosis of the water causes transform of the rock pore pressure from highly inhomogeneous distribution into relatively homogeneous distribution with time. The evolution of the earthquake sequences induced by water injection in Jiao 7 oil well is related to this kind of physical process.
出处
《地震学报》
CSCD
北大核心
1990年第4期399-406,463,共8页
Acta Seismologica Sinica
