物理模拟融合油藏精细刻画法表征特低渗油藏中高含水期剩余油分布

Characterization of remaining oil distribution in ultra-low permeability reservoirs during middle-high water cut by physical simulation combined with reservoir fine sculpture method

中国低渗透油藏分布广泛,其中大部分区块已进入中高含水期,并且由于剩余油类型及成因不明确导致采出程度普遍较低,因此延长低渗透油藏稳产期是亟需解决的问题。结合井口生产资料和储层水驱前缘波及系数对油藏模型进行历史拟合,建立了特低渗油藏剩余油的精细刻画模型,并综合利用静动态物理模拟实验、生产资料动态分析等方法,明确了特低渗油藏中高含水期剩余油成因及类型,据此提出了针对性的剩余油挖潜策略,最终在姬塬油田耿155区长1特低渗油藏进行了现场应用。研究结果表明,特低渗油藏剩余油主要分为储层平面和垂向非均质性导致的储层非均质型剩余油、局部储层注采不对应导致的注采不完善型剩余油以及储层黏土矿物运移膨胀导致的欠注型剩余油,针对性挖潜后目标井组采出程度提高5.1%~12.4%。经现场应用后,预测原油累计采出量相比原始措施提高15.6%~37.3%,为特低渗油藏中高含水期挖潜提供理论和技术支撑。

Low permeability oil reservoirs are widely distributed in China,and most of these blocks have entered the middle stage of development,so prolonging the stable production period of low permeability oil reservoirs is a problem that needs to be solved urgently.This paper combines the wellhead production data and reservoir water-driven leading edge wave and coefficient of the reservoir model for historical fitting,established a fine portrayal model of residual oil in ultra-low permeability reservoirs,and comprehensively utilized the static-dynamic physical simulation experiments,dynamic analysis of the production data and other methods,clarified the causes and types of residual oil in the ultra-low permeability reservoirs in the period of middle-high water cut,and thus put forward the targeted residual oil dredging strategy,which was finally applied in the Jiyuan oilfield Geng155 ultra-low permeability reservoir.The indoor study found that the residual oil is mainly divided into non-homogeneous residual oil caused by reservoir planar and vertical non-homogeneity,and the recovery degree of the target well group is improved by 5.1%~12.4%after dredging.After field application,the predicted cumulative crude oil recovery was increased by 15.6%~37.3%compared with the original measures,which can provide theoretical and technical support for dredging in ultra-low permeability reservoirs in the middlehigh water cut period.