鄂尔多斯盆地林镇地区三叠系延长组长3段砂岩储层特征

Characteristics of the Chang 3 Reservoir in the Yangchang Formation,Linzhen Area,Ordos Basin

林镇地区位于鄂尔多斯盆地西南部,是盆地内重要的油气勘探开发区域之一。为进一步丰富林镇地区长3段储层特征,本文在林镇地区系统采集了长3段储层砂岩样品,利用岩矿分析、物性分析、扫描电镜、压汞资料和测井数据,深入探讨了长3储层的岩石学特征、储层物性特征、成岩作用、成岩阶段及成岩序列等特征,并系统分析了成岩作用对储集物性的影响。研究结果表明认为林镇地区长3段储层砂岩为低孔低渗储集岩,砂岩类型主要为长石砂岩和岩屑长石砂岩。储层砂岩经历了压实作用、胶结作用和溶蚀作用,现处于早成岩阶段B期。孔隙类型以原生粒间孔和次生粒间溶孔为主。储层砂岩经历的压实作用和碳酸盐胶结作用是降低岩石孔隙度和渗透率的主要作用,而溶蚀对岩石孔隙度和渗透率有建设性作用。

In order to acknowledge the characteristics of the Chang 3 reservoir in the Linzhen area, a key oil and gas exploration area, which locates in the southwest Ordos Basin, reservoir sandstone samples and field data were sys- tematically collected from this area. Petrologic characteristics, reservoir physical properties, diagenesis, diagenesis stage and diagenesis sequence and factors affecting reservoir properties were studied via rock-mineral analyses, physical property analyses, scanning electron microscope, mercury penetration data and logging data analyses. The results showed that the reservoir sandstone of Chang 3 is of low porosity and low permeability. The reservoir, com- posed by arkose and debris-feldspar, is in the early diagenetic stage B period and have experienced compaction, ce- mentation and dissolution. The pores are mainly intergranular pores and dissolved pores between grains. The com- paction and carbonate-cementation destroye the primary-texture of pores intensively to deteriorate the physical property, while the chlorite-cementation and dissolution improve the physical property of the reservoir.