成岩作用对致密砂岩储层储集性的控制作用研究——以川西新场气田上沙溪庙组气藏为例

CONTROL OF DIAGENESIS ON THE TIGHT SANDSTONE RESERVOIRS Taking the gas reservoir of Upper Shaximiao Formation in Xinchang gas field, Western Sichuan Basin as an example

在新场气田上沙溪庙组气藏储层宏观沉积特征研究的基础上，采用岩石薄片、铸体薄片、扫描电镜及Ｘ射线衍射等方法，对该气藏储层的成岩作用及其对储集性的影响进行了深入系统的探讨。总结出了晚成岩Ｂ期的溶蚀作用形成的次生孔隙是与烃类气体运移相匹配的，是天然气聚集的主要储集空间；而中晚期的方解石胶结则是形成成岩封闭的关键。据此，结合储层渗透率的差异将上沙溪庙储层划分为４种类型的储渗体，其中相对高渗透体和低渗透体两种类型最具开发前景。

Based on the study of megascopic depositional characters in the upper Shaximiao Formation of Xinchang gas reservoir, the diagenesis and its influence on the reservoir characteristics are discussed systematically in this paper. The used methods are core thin section, moldic thin section, scanning electron microscope and X ray diffraction. The conclusion is that the secondary pores caused by the dissolution of the late B period diagenesis match the migration of hydrocarbon and they are the main spaces accumulating the oil and gas, while the cementation of middle late period calcite is the key that diagenesis was involved. According to the permeability difference, the reservoir could be divided into 4 types and both of the relatively high body and the low permeability body are the best types that could be developed .