【摘要】 在共反射点三维道集的地震资料中,振幅不仅随入射角变化而变化,而且也随方位角变化而变化。振幅随方位角的变化与地层的各向异性具有一定的对应关系,尤其当地层出现一定方位的裂缝时,近平行裂缝和近垂直裂缝方向上共反射点道集的AVO属性参数会表现出明显的差异,这种差异的大小和平面展布正好反映了裂缝的发育程度和分布。本文在对三维纵波道集资料进行叠前时间偏移的基础上,分别抽取沿主测线和联络测线两个方向的道集资料进行AVO异常属性参数分析,然后对比分析两个方向的属性参数的差异,最后应用差异的大小和分布检测了裂缝的发育状况。结果表明,这种方法预测的裂缝与钻井取心和成像测井反映的裂缝发育状况有较好吻合性,与相干体所指示的断裂分布也有一定的关系。更多还原

【Abstract】 In seismic data of 3-D CRP gather, the amplitude changes not only with variation of incident angles, but also with variation of the azimuths. The later has corresponding relationship to the anisotropy of strata, especially when the fracture with some azimuth is appeared in the strata. The AVO attribute parameters may show distinctive difference on CRP gathers between near-parallel and near-vertical to the fractural direction, the size and planar distribution of which just reflect the developing level and distribution of fracture. On the basis of prestack time migration for 3-D P-wave gathers data, the paper carried out analysis of AVO anomalous attributes parameters on gathers data sorting from inline and crossline directions respectively, then, analyzed the difference of attributes parameters between these two directions, and finally applied the size and distribution of the difference to detect the development of fracture. The results showed the development of fracture predicted by the method and reflected by drill core and imaging logging is coincidence, and fracture predicted by the method has some relationship with the distribution of fracture pointed by coherent body.更多还原