川中地区上三叠统须家河组二段和四段沉积相

Study on sedimentary facies in second and fourth members of Xujiahe Formation of upper Triassic in central Sichuan Basin

在沉积学和石油地质学的基础上,综合应用测井、录井、钻井和岩心资料,对川中地区上三叠统须家河组二段和四段进行了高精度的沉积相研究,探讨了储集砂体的展布规律。川中地区上三叠统须家河组产油气层主要分布于浅湖砂坝、三角洲前缘河口砂坝、水下分支河道,部分席状砂、水上分支河道以及心滩微相也是良好的储层。建议今后勘探应注重三角洲平原亚相和前缘亚相的分支河道砂、河口砂坝中的块状粗—中砂岩储层。

Upper Triassic sandstones in Sichuan Basin is an important target for petroleum exploration. Reservoir physical properties are determined by the sedimentation. Based on synthesized core observation and a large number of drilling and logging data, the sedimentary facies in second and fourth members of Xujiahe Formation in upper Triassic in central Sichuan Basin have been thoroughly investigated, and the distribution of reservoir sandstone bodies is also examined. The oil - gas producing strata in Xujiahe Formation in this area are mainly located in shallow lacustrine sand bars, river mouth bars in the delta front, submerged branch channels, sheet sands, branch channels above water and point bars in delta plain. In these microfacies, branch channel sand in delta, point bar, mouth bar and shore sand beach and shallow lacustrine sand bar are the good reservoirs. It suggests that the reservoirs with the branch channel sand in the delta plain and front and coarse to medium sandstones are the impor-tant exploration targets in the future.