伊通盆地莫里青断陷西北缘双阳组二段储层敏感性流动实验评价

Study on flow test evaluation of reservoir sensitivity in second member of Shuangyang formation, northwest edge of Moliqing fault depression, Yitong basin

伊通盆地莫里青断陷西北缘双阳组二段是莫里青油藏的主要产油层位,该油藏储层为中低孔超低渗透储层,储层敏感性对其物性影响较大,所以研究其储层敏感性对防止储层伤害和油田高效开发意义重大。在分析双阳组二段矿物成分和岩石性质的基础上,采用储层敏感性流动实验评价方法,对其储层敏感性进行了评价。结果表明:储层的速敏指数平均为37.23%,水敏指数平均为66.08%,盐敏临界矿化度为6272mg/L,酸敏指数平均为-31.37%,碱敏指数平均为7.71%;研究区储层属于强水敏性、中等偏强盐敏性、中等速敏性、弱碱敏性和无酸敏性储层。研究区储层中存在高岭石、伊/蒙混层、伊利石及绿泥石等粘土矿物,这些敏感性粘土矿物是造成储层伤害的重要因素。因此,在对研究区油藏进行施工时,应将防止水敏、盐敏和速敏放在首位,再考虑其他因素的影响,有针对性地采取措施来保护储层。

The second member of Shuangyang formation in Moliqing fault depression is the main hydrocarbon exploration target in the Yitong basin. Given the low porosity and permeability, we have studied the damage factors of the reservoir in the mining process, and analyzed the susceptibility of the second member of Shuangyang formation which is located in the northwest edge of Moliqing fault depression with the experiments of reservoir flow sensitivity on the basis of understanding the nature of the rock and mineral composition characteristics. The analysis results show that the water sensitivity index of 66.08% on average, with the critical salinity 6 272 mg/L, speed sensitivity index of 37.23% on average, acid sensitivity index of -31.37% on average and the average alkaline sensitivity index of 7.71%. It shows that the reservoir has the strong water sensitivity, moderate-strong salt sensitivity, moderate speed sensitivity, weak alkaline sensitivity and no acid sensitivity. There are many sensitive clay minerals like kaolinite, chlorite, smectite mixed-layer and illite, and the distribution characteristics of these sensitive clay minerals is the most important factor in the mining process. Therefore, when operation is done on the second member of Shuangyang formation of Moliqing oil reservoir, it should prevent speed sensitive and water sensitive firstly. Other sensitive factors should be taken into account to take corresponding measures to protect the reservoir.