四川盆地J地区志留系龙马溪组页岩裂缝地震预测与评价

Seismic Prediction and Evaluation of Fractures in Silurian Longmaxi Shale at J Area in Sichuan Basin

利用三维地震资料进行相干体分析﹑应力场分析﹑P波各向异性分析,对四川盆地J地区龙马溪组优质页岩层段不同规模裂缝的优势发育带进行预测,对比分析表明,对于大型裂缝的预测,相干体分析相对较好;对于中小型裂缝的检测,采用P波各向异性技术的效果相对较好。龙马溪组页岩段底部在构造主体部位上主要发育中小型裂缝,是优质页岩储层的主要分布层段。JY1井区两口水平井的测试结果证实,对龙马溪组优质页岩段开展三维地震裂缝预测是可行的,预测结果可有效地指导该区的页岩气勘探。

Three analysis technologies involving coherence body, stress field and P-wave anisotropy have been applied to the Silurian Longmaxi shale at J area in Sichuan basin to predict the zone of well-developing fractures. The result of comparative analysis shows that the coherence body analysis is fit to the prediction of large fractures while the P wave anisotropy analysis is better to the prediction of middle and/or small fractures. The lower part of Longmaxi shale in which middle and/or small fractures develop commonly is good quality reservoir. Depending on the test result of two horizontal wells at the area of Well JY-1, it is confirmed that the method of 3-D fracture prediction is available to good quality reservoir of Longmaxi shale, which is significant for shale gas prospecting in this area.