志丹正359井区延长组长4+5段剩余油分布主控因素分析

Analysis on the Main Controlling Factors of Residual Oil Distribution in Chang-4+5 Section of Yanchang Formation in Zheng-359 Well of Zhidan Area

志丹油田正359井区处于中含水阶段,剩余油的分布和挖潜成为未来一阶段油田增产的主要攻关目标。为深入研究鄂尔多斯盆地志丹地区三叠系延长组长4+5段储层剩余油分布特征,文中总结前人研究成果,并通过沉积、构造、储层特征及生产动态资料分析,综合研究长4+5段储层的剩余油富集规律及控制因素。研究认为,长4+5段储层剩余油主要分布在河道侧翼至分流间湾沉积相,且剩余油富集位置隔夹层发育,注采井网不完整,存在隆起构造;储层孔隙微观特征为剩余油富集的主要控制因素;长4+5段储层孔喉半径集中在0.016~0.063μm,孔喉流动半径下限为0.107μm,孔喉流动半径下限最终决定储层中的剩余油富集总量。

Zheng-359 well area of Zhldan oilfield has entered aquifer stage, distribution and potential of remaining oil will become the main research target of increasing production in the next stage of oilfield. In order to further study distribution characteristics of remaining oil in Chang-4＋5 reservoir of Triassic Yanchang formation in Zhidan area, based on the previous research, we researched characteristics of remaining oil distribution and main controlling factors in Chang-4＋5 reservoir through deposition, structure, reservoir characteristics and production dynamic data analysis. It was concluded that remaining oil in Chang-4＋5 reservoir is mainly distributed in river facies to diversion bay sedimentary facies, and remaining oil enrichment area developed separators and interlayers, injection and production well is not perfect, and uplift structure exists. Pore microstrueture is the main factor affecting distribution of residual oil. Pore throat radius of Chang-4＋5 reservoir is 0. 016-0. 063μm, lower limit of flow pore throat is 0. 107μm, it finally determines total amount of residual oil.