川西新场地区中三叠统雷口坡组顶部风化壳裂缝分布特征及预测

川西中三叠统雷口坡组是四川盆地增储上产的重要阵地。近期，川西新场地区首次在雷口坡组顶部风化壳储层试气获工业气流，溶蚀孔洞和裂缝是主要的储集空间和渗流通道，如何准确预测雷口坡组顶部风化壳储层裂缝的分布特征，成为推动该地区勘探进程的关键。利用岩心观察和成像测井资料明确裂缝发育的地质特征，并采用相干、倾角、方位角和曲率属性等地震裂缝预测方法识别裂缝发育带的平面展布特征。雷口坡组顶部风化壳储层裂缝以中低角度为主，走向为北东—南西、北西—南东和近东西向；研究区中东部构造裂缝相对发育，主要发育在大断层附近；西南部发育北东—南西、北西—南东向“网状”层间裂缝，其中北东向裂缝规模较大。综合多种方法的分析结果，确定了雷口坡组顶部风化壳储层的裂缝发育特征及分布规律，预测结果与新钻井吻合较好，为下一步评价部署提供了可靠依据。 

Fracture distribution and prediction of weathering crust reservoirs on the top of Leikoupo Formation,Xinchang area,western Sichuan Basin

The Leikoupo Formation in the western Sichuan Basin is an important potential stratum for the increasing of reserves and production. Recently, industrial grade gas flow has been discovered for the first time from weathering crust reservoirs on the top of Leikoupo Formation in the Xinchang area. Dissolution pores as well as fractures are the main storage spaces and seepage channels. Then, how to accurately predict the distribution characteristics of these cracks in weathered crust reservoirs has become a key factor of advance exploration process. Core observation and imaging logging data were applied to clarify the geological characteristics of fracture development. Some seismic prediction methods such as coherence, dip, azimuth and curvature attributes were used to identify the plane distribution characteristics of fracture development zones. Results show that the fractures in weathering crust reservoirs on the top of Leikoupo Formation are mainly in the middle and low angles, and the strikes are NE-SW, NW-SE and near EW. Structure fractures are mainly distributed in the central and eastern area and near the big fault. In the southwest of the study area, there are NE-SW and NW-SE "net-like" interlayer fractures, of which the scale of the NE fractures is larger. Based on the analysis results of multiple methods, the fracture characteristics and distribution rules of weathered crust reservoirs on the top of Leikoupo Formation were determined. The prediction results are consistent with newly drilled wells and provide a reliable basis for the evaluation in future.