注CO2混相驱油藏合理采收率确定

Determination of Reasonable Recovery Ratio with CO2 Miscible Flooding in Reservoir

唐人选 唐小立 秦红祥

Tang Renxuan Tang Xiaoli Qin Hongxiang

中国石化华东分公司采油厂, 江苏泰州 225300; 中国石化石油工程技术研究院, 北京 100101

Oil Production Plant of East China Branch Company, Sinopec, Taizhou, Jiangsu, 225300, China; Sinopec Research Institute of Petroleum Engineering, Beijing, 100101, China

为确定CO2混相驱油藏合理采收率,基于水驱油分流量方程、Buckley-Leverett水驱油非活塞理论及 CO2混相驱特性(即混相驱油藏不存在界面张力,各相渗透率与对应相饱和度成正比),将水驱油分流量方程进行适当改进,其物理性影响因素更加明显,更适用于CO2混相驱油藏,并推导出CO2气体分流系数关系式和原油采出程度与累积注气量之间的关系式,用来设计和预测CO2混相驱开发参数。同时对采出程度与累计注气量之间的数学关系式求导,得到了注CO2混相驱油藏合理采收率导数方程的数学模型,可为计算合理注入CO2量及注CO2混相驱最终采收率提供参考。

In order to determine reasonable recovery for CO2 miscible flooding reservoir,a modified water flooding fractional flow equation is presented in this paper(with more obvious physical factors)to fit CO2 miscible flooding reservoir based on water flooding theory that includes water flooding fractional flow equation,Buckley-Leverett water flooding non-piston theory,and CO2 miscible flooding characteristics(no interfacial tension existed in miscible flooding reservoir,and the permeability of each phase is directly proportional to the saturation of corresponding phase),and derived CO2 gas fractional flow coefficients equation and the equation related to crude oil recovery percentage and cumulative gas injection.The two equations can be used to design and forecast development parameters of CO2 miscible flooding. By deriving the mathematical equation concerning the crude oil recovery percentage and cumulative gas injection,a mathematical model of derivative equation has been established to obtain the reasonable recovery ratio of CO2 miscible flooding,which can provide theoretical reference for calculating reasonable CO2 injection volume and ultimate recovery factor of CO2 miscible flooding.

https://doi.org/10.3969/j.issn.1001-0890.2012.03.023