川西拗陷中段蓬莱镇组储层发育特征及主控因素

Reservoir characteristics and controlling factors of Upper Jurassic Penglaizhen Formation in the middle area of West Sichuan depression,China

研究川西拗陷中段上侏罗统蓬莱镇组储层发育的主控因素,寻找优质储层发育区。通过对储层微观特征分析,结合钻井相关的测试分析资料,研究结果表明,川西拗陷中段蓬莱镇组储层总体上属于中-低孔、低渗型储层,且平面上差异较大,位于研究区中部、东部地区相对远物源富长石类储层物性总体较好。最有利储层发育的沉积环境为分流河道,次为河口坝。压实作用和胶结作用是造成储层中-低孔、低渗最主要的原因;而溶蚀作用是最重要的建设性成岩作用,且胶结物的溶蚀强度大于碎屑颗粒的溶蚀强度。此外,少量的构造破裂缝可以在一定程度上改善储层渗滤能力,同时也为溶蚀作用提供了良好的通道。

The main controlling factors of the Upper Jurassic Penglaizhen Formation reservoir in the middle part of the western Sichuan depression are studied by means of analysis of microscopic characteristics of reservoir, combined with drilling well data and testing data interpretation, in order to find high quality reservoir development areas. It shows that the Penglaizhen Formation is characteristic of low medium porosity and low permeability reservoirs, and differs greatly in the plane. It reveals that the feldspar reservoirs of relative far sources in the central and eastern part of the study area have good physical properties. The most favorable sedimentary environment of reservoir is distributary channel and the estuary dam comes the second. Compaction and cementation are the main reasons responsible for low porosity and permeability of reservoir in the area, while the dissolution is the most important and constructive diagenesis. It shows that the dissolution strength of the cements is high than that of the clasts. In addition, a small amount of structural cracks improve reservoir percolation ability to some extent, and also provide erosion for dissolution pathway.