气顶油藏高含水后期顶部注烃气保压气驱技术

Maintaining Pressure Gas Drive Technology by Injecting Hydrocarbon Gas at Top of Gas Cap Reservoir in Later Stage of High Water Cut

根据K油田Ⅳa断块的地质条件和开发现状,建立顶部注烃气保压气驱数值模型,根据数值模拟计算结果,研究注气井位置、注气速度、采液速度和注气井数量对于顶部注烃气保压气驱效果的影响,提出一种适应气顶油藏高含水后期的开发模式。研究结果表明,气顶油藏高含水后期顶部注烃气保压气驱可有效的提高原油采收率,达到降水增油的效果;注气井位置对于开发效果有一定的影响,注气井应部署在气顶中心位置,远离油气界面;注气速度对于开发效果的影响较大,研究区块的最佳注气速度为0.023 PV/a;提高采液速度不能有效的改善顶部注烃气保压气驱的开发效果;注气井的数量对于顶部注烃气驱的开发效果有一定的影响,研究区块注气井数为5口时,既可以保证开发效果,又可以减少不必要的钻井成本。

According to the reservoir properties and development characteristics of fault block Ⅳa,the numerical model of gas injection in the top gas injection is established. The gas injection well position,gas injection rate,liquid production rate and the number of gas injection wells effects on maintaining pressure gas drive were studied according to the results of numerical simulation. And the development scheme fit to the gas cap reservoirs in high water cut stage was provided. The results show that oil recovery can be enhanced effectively by maintaining pressure gas drive technology by injecting hydrocarbon gas at the top of gas cap reservoir in later stage of high water cut for increasing oil production and decreasing water cut. The development effect is affected by the position of gas injection well. Gas injection wells should be deployed at the center of gas cap. The gas injection rate is the most important factor for the development effect,and the optimum gas injection rate is 0. 023 PV per year. The development effect cannot be improved by increasing liquid production rate,The development effect is affected by the number of gas injection wells. When the number of gas injection wells is five,it can not only ensure the development effect,but also reduce the drilling cost and obtain better economic benefits.