泌阳凹陷地质流体对砂岩储集层中黏土矿物形成和分布的控制作用

Geofluids Control of the Formation and Distribution of Clay Minerals within the Sandstone Reservoir in Biyang Depression

运用扫描电镜观察和X射线衍射分析等技术,在对泌阳凹陷核桃园组砂岩储集层中黏土矿物分布特征研究的基础上,从黏土矿物的形成条件和形成过程入手,详细分析了地质流体的性质、组成、流动方式、迁移速度等对砂岩储集层中黏土矿物形成和分布的影响,指出砂岩储集层中参与成岩反应的碎屑活性组分和地质流体对砂岩储集层中黏土矿物的形成和分布具有控制作用,并讨论了它们的形成机理。研究表明,黏土矿物的形成和分布能够不同程度地影响砂岩储集层的孔渗性和含油气性;高岭石发育层段与次生孔隙的发育和渗透率的增加以及油气的富集层段具有良好的对应关系。

This paper presents the distributive characteristics of clay minerals in the sandstone reservoir in the Hetaoyuan Formation, Biyang Depression. Contents of various clay minerals within the studied sandstone reservoirs obtained by electron microscope scanning and X-ray diffraction are calculated. The clastic active-compositions and geofluids in the reservoirs have a control over the generation of clay minerals and the mechanisms of clay forming are associated with many aspects of geofluids. The formation conditions and courses of clay minerals are related to the property, composition, flowing pattern and moving speed of geofluids, which influenced the formation and distribution of clay minerals in the sandstone reservoirs. This study indicates that the porosity and permeability of sandstones are affected variously by different clay minerals developed in the reservoirs. The study shows that the secondary pore formation,permeability increase and hydrocarbon accumulation within the studied sandstone reservoirs are associated with the occurrence of abundant kaolinite.