基于各向异性理论的地应力地震预测技术研究

Stress seismic prediction based on anisotropic equivalent medium theory

随着非常规油气勘探和开发技术的发展,尤其是页岩油气高效开发的需要,地应力的准确预测对页岩油气水平井轨迹设计和有利压裂区域的选取十分重要。笔者以各向异性等效介质理论为基础,以页岩各向异性岩石物理模型为驱动,基于宽方位地震数据开展高精度的叠前AVAZ反演,获得弹性参数及裂缝岩石物理参数,并结合地应力预测模型,实现地应力大小及方向的定量预测。通过理论模型测试与实际资料应用显示,该方法预测的地应力具有较高的精度,符合地质规律,且与微地震压裂监测结果及测井解释结果具有良好的一致性,有效指导了页岩油气水平井轨迹设计及压裂方案部署。

With the technological development of unconventional oil and gas exploration and development,especially the need for efficient shale oil and gas extraction,accurate stress prediction is crucial for designing shale horizontal well trajectories and selecting favorable fracturing areas.In order to obtain the stress magnitude and direction,firstly,we should get the elastic parameters and fracture rock physics parameters;we carry out the high-precision pre-stack AVAZ inversion using wide-azimuthal seismic data based on the anisotropic equivalent medium theory and then driven by the anisotropic rock physical model of shale.Secondly,combined with the stress prediction model,we realize the quantitative prediction that includes the magnitude and direction of the stress.The theoretical model test and practical data application show that this stress prediction method has high accuracy,the results of stress prediction conform to the geological rule,and have good consistency with the results of micro-seismic fracturing monitoring and log data.It can effectively guide the shale horizontal well trajectory design and fracturing scheme deployment.