摘要
致密砂岩储层孔隙结构复杂,黏土矿物含量高,非均质性强,极易受到外来流体的影响而伤害储层,制约产能。以鄂尔多斯盆地子长东区山西组2段(山2段)致密储层为例,利用岩石薄片、铸体薄片、扫描电镜、X-射线衍射、高压压汞及敏感性评价实验等方法,对储层的敏感性特征进行分析评价,深入剖析其主要影响因素。结果表明:鄂尔多斯盆地子长东区山2段致密储层属于弱速敏—中等偏强速敏、强水敏、弱盐敏—中等偏弱盐敏(临界盐度为12.5~25 g/L),局部存在弱酸敏,整体表现为酸敏改善,无碱敏—弱碱敏。影响储层敏感性的主控因素为黏土矿物(主要为高岭石和伊利石)的数量类型及形态、碳酸盐胶结物(铁方解石和铁白云石)的类型及分布、孔隙结构的复杂多样性及储层的非均质性。研究结果对研究区钻井液、压裂酸化等工艺的优化配置具有指示意义。
The tight sandstone reservoir has a complex pore structure,high clay mineral content,and strong heterogeneity,which is highly susceptible to the influence of external fluids,that can damage the reservoir and restrict productivity.Taking the tight sandstone reservoirs of the second member of the Shanxi Formation(Shan2 Member)in the Zichang East area of Ordos Basin as an example,the sensitivity characteristics of the reservoir were analyzed and evaluated by using the methods of rock slice,cast slice,scanning electron microscope,X-ray diffraction,high-pressure mercury injection,and sensitivity evaluation experiment,etc.and the main influencing factors were analyzed in depth.The results show that the tight sandstone reservoirs of Shan2 member in the Zichang East area of Ordos Basin belong to the categories of weak speed sensitivity-medium strong speed sensitivity,strong water sensitivity,weak salt sensitivity medium weak salt sensitivity(with the critical salinity ranging from 12.5 to 25 g/L),with local weak acid sensitivity,and with the overall performance of acid sensitivity improvement,no alkali sensitivity-weak alkali sensitivity.The main controlling factors affecting reservoir sensitivity are the quantity type and morphology of clay minerals(mainly kaolinite and illite),the type and distribution of carbonate cement(iron calcite and iron dolomite),the complex diversity of pore structure,and the heterogeneity of the reservoir.The research results are instructive for the optimal configuration of drilling fluid and the fracturing and acidizing technology in the study area.
作者
孙细宁
邓长生
徐敏
杜永慧
王宇
SUN Xining;DENG Changsheng;XU Min;DU Yonghui;WANG Yu(Natural gas research Institute of Shaanxi Yanchang Petroleum(Group)Co.,Ltd.,Xi'an 710065,China)
出处
《复杂油气藏》
2024年第2期145-151,共7页
Complex Hydrocarbon Reservoirs
基金
延长石油集团重点研发项目“延451井区山2段储层特征研究及改造、排采工艺优化”(ycsy2022jcts-B-22)。
关键词
敏感性
主控因素
山2段致密储层
子长东区
鄂尔多斯盆地
sensitivity
main controlling factors
tight sandstone reservoirs of Shan2 member
Zichang East area
Ordos Basin
