超前注水流入动态模型在低渗透油藏开发中的应用

在超前注水低渗透油藏生产过程中,原油、注入水及脱出的溶解气在地层中会形成三相流动。为准确表征其渗流特征,将流体在地层中的渗流区域划分为油水两相渗流区和油气水三相渗流区,通过引入三相拟压力函数,考虑非达西效应(启动压力梯度、应力敏感)及油气互溶影响,建立具有拐点的三相流产能方程。研究结果表明,通过自动拟合的方法对非达西渗流参数进行拟合后,该三相流产能模型的计算结果与实测数据一致。4口井实例计算显示:当油井控制在拐点压力下生产时,可提升约195.0%的产量;在高流压阶段各因素对油井产量影响较大,其中含水率影响最为明显。研究成果对超前注水低渗透油藏合理井底流压界限的确定具有实际的指导意义。

Application of Advanced Water Injection Inflow Production Relation Model in Low-Permeability Reservoir

There is a three-phase flow between water, injection water and dissolved gas in the low permeability reservoir with advanced water injection in the production process. In order to further characterize the three-phase seepage performance, the fluid flow in the reservoir was divided into oil-water two-phase seepage zones and oil-gas-water three-phase seepage zones. Based on a three-phase quasi-pressure function, a three-phase flow productivity equation with inflection point was established by considering the non-Darcy effect (starting pressure gradient, stress sensitivity). Research indicates that the test data is consistent with the calculation of three-phase seepage model after automatic fitting of non-Darcy flow parameters. Application of 4 wells shows that the production can be enhanced by about 195.0% when the production well is controlled below the inflection pressure. Multiple factors show a significant influence on the well production in the high flowing pressure stage, and the water cut is considered as the most sensitive factor. This research could provide certain guidance for the determination of reasonable bottom hole flowing pressure limit in low permeability reservoir with advanced water injection.