Diagenesis and pore evolution of tight sand reservoir of the Permian Longtan formation in Huangqiao area, lower Yangtze region
Li Lingli;Ma Weijun;Research Institute of Petroleum Exploration and Development,East China Company,SINOPEC;
Sandstone reservoir of the Permian Longtan formation in Huangqiao area, lower Yangtze region has poor properties and belongs to tight sandstone reservoir. Through the observation of the cores of multiple wells, the identification of rock slices, scan ning electron microscopy and X-ray diffraction analysis of clay mineral, the reservoir diagenesis and the pore evolution process were recognized and restored. The research results show that the diagenesis of sandstone of Longtan formation are compaction, ce mentation, metasomatism, denudation and pressolution, which affect a lot on pore development. The compaction and cementation are the main factors which cause the densification of the reservoir. The denudation of feldspar, clastic debris, matrix and quartz is the main factor to form the secondary pore, which obviously improves the storage performance of the tight sandstone.