下扬子地区海相储集岩特征及含油气性

下扬子地区海相储集岩经过长期压实和地史演化,原生孔隙度和渗透率急剧减小,大部分岩石呈低孔、低渗特征。然而对于刚性致密的碳酸盐岩以及厚层块状砂岩,次生裂隙(缝)、溶隙相对发育,它们分布于四套主要的刚性岩层中,极大地改善了这些岩石的孔渗性能,使之成为良好的裂隙储集体,为海相中生界、古生界油气聚集成藏提供了有利的储集空间。

CHARACTERISTICS OF MARINE RESERVOIR ROCKS AND THEIR HYDROCARBON-BEARING PROPERTIES IN LOWER YANGTZE AREA

Through a long-term compaction and geological history, the orlginal porosity and permeability of the marine reservoir rocks in the Lower Yangtze area are greatly decreased, most of them are characterized by low porosity and low permeability. However, these rigid and dense carbonates and thick-bedded sandstones are of relatively developed secondary fractures (fissures) and solutional pores, which are mainly distributed in four suites of rigid rocks. So the porosity and permeability of these rocks are greatly improved and these rocks become good fracture reservoirs, which provide favorable reservoir spaces for the Meso-Paleozoic marine hydrocarbon accumulation.