陕北斜坡东南部致密砂岩孔喉分布及其对含油性的影响

Pore throat distribution of tight sandstone in the southeast of the Northern Shaanxi Slope and its influence on oil?鄄bearing property

钟红利 吴雨风 张凤奇 屈伸 陈玲玲3

西安科技大学地质与环境学院，陕西 西安 710054 西安石油大学地球科学与工程学院，陕西 西安 710065 陕西延长石油（集团）有限责任公司研究院，陕西 西安 710075

Gollege of Geology & Environment, Xi′an University of Science and Technology, Xi′an 710054, China School of Earth Science and Engineering, Xi′an Shiyou University, Xi′an 710065, China Research Institute of Shaanxi Yanchang Petroleum (Group) Co. Ltd., Xi′an 710075, China

为探究鄂尔多斯盆地陕北斜坡东南部地区致密砂岩储层的微观孔喉分布及其对含油性的影响，对长6—长8致密砂岩样品进行了场发射扫描电镜、高压压汞、核磁共振等测试，定量表征了其微观孔喉分布特征，分析了孔喉参数与含油性的关系。结果表明：研究区长6—长8致密砂岩储层孔隙类型主要为残余粒间孔、溶蚀孔、晶间孔；最小孔隙半径为0.5~6.3 nm，最大孔喉半径为1 863.8~33 859.7 nm；纳米孔、亚微米孔占总孔隙体积的61.2%~93.3%，微米孔占总孔隙体积的6.7%~38.8%，基本不发育毫米级孔隙。孔隙中的油水相分布峰值为50~100 nm。砂岩含油率与50 nm以上孔喉占比正相关，与亚微米孔占比正相关，与孔喉分选系数负相关。该研究成果对研究区致密砂岩含油性预测具有参考意义。

In order to explore the micro pore throat distribution and its influence on oil?鄄bearing property of tight sandstone reservoirs in the southeast of Northern Shaanxi Slope in Ordos Basin, field emission scanning electron microscopy, high?鄄pressure mercury injection and nuclear magnetic resonance (NMR) tests were carried out on Chang 6￣Chang 8 tight sandstone samples to quantitatively characterize their micro pore throat distribution characteristics, and the relationship between pore throat parameters and oil?鄄bearing property was analyzed. The results show that the pore types of Chang 6￣Chang 8 tight sandstone reservoirs are mainly residual intergranular, dissolution pores and intercrystalline pores; the minimum pore radius is 0.5￣6.3 nm; the maximum pore throat radius is 1,863.8￣33,859.7 nm; the nano and submicron pores account for 61.2%￣93.3% of the total pore volume, and the micro pores account for 6.7%￣38.8% of the total pore volume, basically no millimetre pore is developed. The peak distribution range of oil and water phases in the pores is 50￣100 nm. The oil content of sandstone is positively correlated with the proportion of pore and throat above 50nm, positively correlated with that of submicron pore, and negatively correlated with the sorting coefficient of pore throat. The conclusion has reference significance for oil?鄄bearing property prediction of tight sandstone in study area

10.6056/dkyqt202101004