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针对高邮凹陷南断阶特低渗透油藏储层物性较差、不同区块开发难易程度差异较大等问题,综合应用恒速压汞、核磁共振、离心实验及油水驱替等实验技术对储层微观孔隙结构、油水渗流机理及核磁共振可动流体百分数等进行了系统研究,并根据五元分类系数法对不同区块进行了储层评价和分类优选。结果表明,南断阶特低渗透油藏泰州组储层物性优于阜宁组,不同渗透率储层喉道发育特征差异较大而孔道分布特征基本相同,渗透率越小则微孔隙越发育;储层主流喉道半径与渗透率之间具有较好的指数关系。泰州组和阜宁组储层可动流体百分数平均值分别为67.2%和32.9%,阜宁组可动流体百分数从大到小依次为陈2、竹墩、许庄、方巷和徐31区块。水驱过程中油相渗透率随含水饱和度的增加而急剧减小,但水相渗透率增加幅度很小,水驱油效率平均值为54.1%;水驱后储层较大孔隙空间仍含有一定量残余油,而微小孔隙中的原油基本未被驱替出来。研究区特低渗透油藏不同区块储层开发难易程度从低到高依次为:竹墩区块泰州组,陈2、许庄、竹墩、方巷和徐31区块阜宁组。
In view of the poor reservoir physical properties and the difficulty of development in different blocks in the Nanchangdian low-permeability reservoir in the Gaoyou sag, comprehensive application of experimental techniques such as constant velocity mercury injection, nuclear magnetic resonance, centrifugal experiments and oil-water displacement Reservoir microscopic pore structure, oil-water seepage mechanism and the percentage of NMR movable fluid were systematically studied. According to the five-element classification coefficient method, the different blocks were evaluated and classified according to their classification. The results show that the reservoir properties of the Taizhou Formation in the Nanchang low-permeability reservoirs are better than that of the Funing Formation. The throat development characteristics of reservoirs with different permeability are quite different while the distribution characteristics of the tunnels are basically the same. The smaller the permeability, the more micro-pores develop There is a good exponential relationship between the main throat radius and permeability in the reservoir. The average percentages of movable fluid in Taizhou Formation and Funing Formation are 67.2% and 32.9%, respectively. The percentage of movable fluid in Funing Formation is Chen 2, Zhudian, Xuzhuang, Fangxiang and Xu 31 Piece. The permeability of oil phase decreases drastically with the increase of water saturation during water flooding, but the increase of water phase permeability is small, and the average of water flooding efficiency is 54.1%. After the water flooding, the larger pore space of reservoirs still contains certain The amount of residual oil, while the tiny pores of the crude oil is basically not driven out. The development difficulty of reservoirs in different blocks of the ultra-low permeability reservoirs in the study area are in order from low to high: Taizhou Formation, Chen 2, Xuzhuang, Zhudian, Fangxiang and Xu 31 blocks of Funing Formation in Tadun block.