苏里格气田东部致密砂岩储层的沉积-成岩约束

鄂尔多斯盆地苏里格气田是我国陆上产能最大的气田,而储层低孔低渗的特点是制约该气田开发的关键因素。为了探讨砂岩储层低孔低渗的成因机理和主控因素,在岩心观察、薄片鉴定、流体包裹体分析、X-射线衍射、阴极发光分析、扫描电镜分析等基础上,进行了系统的沉积微相和成岩作用研究。研究表明,主要产气层山1、盒8段砂体形成于辫状河心滩、辫状河道及曲流河边滩等水动力条件强的沉积微相;成岩作用无疑是砂岩储层物性变差的主要原因;但沉积微相奠定了岩石结构和沉积期后作用的物质基础,对成岩作用和储集性能产生重要影响。

Deposition and Diagenesis Restrictions on tight sandstone reservoirsin the eastern Sulige gas field, Ordos basin

Sulige gas field is the largest terrestrial gas production field in China. But characteristics of low-porosity and low-permeability are main controlling factors to the gas exploitation. In order to probe for genesis and controls of low-porosity and low-permeability sandstone reservoirs in the eastern Sulige gas field in Ordos basin, studies on detailed sedimentary facies and diagenesis was conducted by core observation, thin section identification, fluid inclusion analysis, X-ray diffraction analysis, cathodeluminescence analysis and scanning electron microscope analysis. Studies show that sand bodies of main gas reservoirs in Shan1 members (P₁s₁) and He8 members (P₂h₈) were formed in detailed sedimentary facies such as channel bar, braided channel of braided river and point bar of meandering river, for which deposited in relatively high hydrodynamics. It is no doubt that diagenesis was the main reason for decreasing of physical property of sandstone reservoirs. But detailed sedimentary facies not only settled lithological texture but also material foundation of diagenesis. As a result, detailed sedimentary facies play important roles on diagenesis and physical properties of sandstone reservoirs.