合水地区长6储层微观孔隙结构研究

Study on Micro Pore Structure of Chang 6 Reservoir in Heshui Area

为了研究储层微观孔隙结构,明确储集空间类型和油气储层储集性能,对油气储层进行分类评价,进行油气储层预测,为提高采收率提出了针对性建议。以鄂尔多斯盆地合水地区延长组超低渗-致密储层岩性特征、构造演化以及沉积特征研究成果及认识为理论基础,通过铸体薄片图像分析、扫描电镜分析、恒速压汞等技术方法,对长6致密砂岩储层微观孔隙结构特征进行了深入研究。结果表明合水地区长6储层面孔率均值为2.23%,以残余粒间孔、长石溶孔和岩屑溶孔为主。样品的渗透率越大,喉道半径就越大,孔喉比就越低,喉道是控制渗透率的根本因素。有效储集空间、孔喉配置决定驱油效率,有效储集空间越大和孔喉配置越好,驱油效率越高。

In order to study the microscopic pore structure,define the types of reservoir space and the reservoir performance of oil and gas reservoirs,classify and evaluate the oil and gas reservoirs,predict the oil and gas reservoirs,and put forward some suggestions for improving oil recovery,the Chang 6 tight sandstone reservoir microscopic pore structure characteristics were studied through the casting sheet image analysis,scanning electron microscopy and constant-rate mercury injection,on the basis of the research findings and understanding of the lithology characteristics,tectonic evolution and sedimentary characteristics in the ultra low permeability reservoir in Ordos basin of Heshui area of Yanchang Formation. The results show that faces rate in the Chang 6 reservoir in Heshui area was 2. 23%,the residual intergranular pore,feldspar dissolved pore and debris dissolved pores took the principal parts; the greater the permeability of the sample,the larger the throat radius and the lower the throat to throat ratio,and the throat was the fundamental factor controlling permeability; the effective reservoir space and pore throat configuration determined the oil displacement efficiency; the larger the effective storage space and the better throat arrangement,the higher the oil displacement efficiency.