川西新场构造须四段储层特征及主控因素

Reservoir characteristics and controlling factors in the 4th member of the Xujiahe Formation in the Xinchang structural zone, western Sichuan

关键词:  川西  新场构造  须家河组  有利储层  主控因素

Key words:  western Sichuan  Xinchang structural zone  Xujiahe Formation  favourable reservoir  controlling factor

摘要:

利用岩心观察、岩石薄片分析、阴极发光和扫描电镜等方法对川西新场地区须四段储层的岩石学特征、储集空间类型及物性特征进行分析,讨论沉积环境、成岩作用及构造作用等对储层的影响。研究区储层经历了压实作用、胶结作用、溶蚀作用和交代作用等成岩作用。有利储层主要发育在分选性中等-好、杂基含量低的中细粒砂岩中。主要储集空间以次生孔隙为主,其次为残余粒间孔。高能环境下的分流河道和河口坝是形成有利储层的先决条件,而后期长石及岩屑溶蚀产生的次生孔隙、裂缝的发育是形成有利储层的关键。

Abstract:

With the aid of core observation, thin section examination, CL and SEM, the present paper deals with petrology, reservoir space types and physical properties, and the effects of sedimentary environments, diagenesis, tectonism on reservoir potential of the reservoir rocks in the Xujiahe Formation in the Xinchang structural zone, western Sichuan. The diagenetic processes of the reservoir rocks in the study area include compaction, cementation, dissolution and replacement. The favourable reservoir rocks occur in the medium-to fine-grainded sandstones with moderate to good sorting and low matrix contents. The reservoir space types contain intergranular and intragranular solution openings. The distributary channels and channel mouth bars are believed to be favourable sites, and secondary porosity and fissures may improve the reservoir quality of the reservoir rocks in the study area.