高倾角厚油层注水开发影响因素数值模拟——以H断块P油藏为例

Numerical simulation of factors affecting water injection development in high dip and thick oil layers:a case study of P reservoir in H fault block

油水重力分异作用对高倾角厚油层注水开发效果影响较大,以H断块P油藏为研究对象,结合实际油藏地质参数,建立高倾角厚油层机理模型,并应用数值模拟方法系统研究了注采位置、地层倾角、油层厚度、储层韵律、注采比、采油速度、地层压力保持水平等7个主要因素对注水开发效果的影响。结果表明,构造低部位注水高部位采油和较大的地层倾角有利于发挥油水重力分异作用从而提高采收率;油层厚度增大采收率降低;反韵律储层因底部较低的渗透率抑制了注入水的重力低伏,采收率较其他韵律储层更高;最佳注采比为1.0,最佳采油速度为3.0%,地层压力保持在原始地层压力的70%~80%时,可以获得更好的开发效果。研究成果可为此类油藏制定注水开发策略提供参考。

The gravity differentiation of oil and water has a great influence on the water injection development of high dip and thick oil layers.Taking P reservoir of H fault block as the research object,combined with actual geological parameters,a mechanism model for high dip thick oil layers is established.Therefore,the numerical simulation method is applied to study the effects of main factors on water injection development,including injection-production structural position,formation dip angle,reservoir thickness,reservoir rhythm,injection-production ratio,oil recovery rate,and formation pressure maintenance level.The results indicate that water injection in low structural parts and oil production in high parts,as well as a larger formation dip angle,are beneficial for exerting the gravitational differentiation effect of oil and water,thereby improving oil recovery;the increase in oil layer thickness leads to a decrease in oil recovery;the lower permeability at the bottom of the anti-rhythmic reservoir suppresses the gravity depression of injected water,resulting in higher oil recovery compared to other rhythmic reservoirs;the optimal injection production ratio is 1.0,the optimal oil production rate is 3.0%,and the maintaining level of formation pressure at around 70%~80% of the original formation pressure can achieve better development results.The research results can provide a good reference for the water injection development of similar reservoirs.