高邮凹陷南断阶阜一段储层特征及物性主控因素

Reservoir characteristics of the first member of Funing Formation in south fault terrace of the Gaoyou sag and the main controlling factors on physical properties

不同低渗透储层特征差异大,尤其是物性特征对渗流能力和开发效果有着重要影响。以岩芯为基础,综合采用普通薄片、铸体薄片等多种测试手段对高邮凹陷南断阶阜一段储层特征进行分析,结合岩石相、沉积相、成岩特征研究储层物性的控制因素,探讨低渗透砂岩背景下的优质储层形成条件。研究结果表明:高邮凹陷南断阶阜一段储层为低孔低渗透储层,其成分和结构成熟度中等,孔隙度一般为15%,渗透率一般为10×10-3μm2。沉积作用是形成低渗透储层的基础性因素,控制着砂体的发育,决定了后期成岩作用的类型和强度;成岩作用的压实作用、胶结作用和溶蚀作用对储层物性起决定性作用,优质储层的形成主要受后期碳酸盐溶蚀作用控制。寻找次生孔隙发育储层是该地区下一步油气开发的方向和突破点。

The characteristics of different low permeability reservoirs vary greatly, and especially the physical characteristics have an important impact on the seepage capability and development efficiency. This study analyzed the reservoir features of the first member of the Funing Formation in south fault terrace of the Gaoyou sag with conventional thin section and casting thin section techniques based on core data. In addition, we studied the controlling factors of reservoir physical properties combining with lithofacies, sedimentary facies and diagenetic characteristics, and discussed the formation conditions of high-quality reservoir in low permeability sandstone. The result shows that this reservoir has moderate compositional maturity and textural maturity, and low porosity and permeability, with average po- rosity of 15% and average permeability of 10~ 10-3 ~Lm2. Sedimentation is a basic factor of this low permeability reservoir, which con- trols the development of sand bodies and determines the type and intensity of the late diagenesis. The compaction, cementation and dis- solution of rocks are critical to the reservoir physical properties. The formation of high-quality reservoir is mainly controlled by carbonate dissolution. Those reservoirs with secondary pores are the direction and breakthrough of the oil and gas development in the region.