复杂断块油田中高含水期油水渗流规律研究

Water-oil Percolation Law of Complex Fault Block in Middle and High Water-cut Stage

针对冀东油田主力油层2个区块天然岩心的3个不同含水阶段,研究复杂断块油田进入中高含水期后储层物性的变化及油水渗流规律。用分形维数表征孔隙结构参数,采用分段拟合回归分析大孔隙与小孔隙的物性差别,绘制含水率与含水饱和度、驱替效率、无因次采油指数采液指数的关系曲线。分析结果表明:随着注入水的增加,孔隙度渗透率增大,稠油油藏孔隙度增加幅度更大,岩石的亲水性增强,大小孔隙的分形维数均减小,岩心非均质性变弱;随着含水率增加,驱替效率增加,高含水阶段增长变缓;无因次采油指数随着含水率的升高而下降,当至高含水期时,稠油油藏采油指数急剧下降,稀油油藏采油指数趋于稳定;稠油和稀油油藏的无因次采液指数均急剧上升,进入水洗阶段,稀油油藏适合整体提液,稠油油藏应在含水80%前提液。

In view of the oil field main oil layer in Jidong two real core sample＇s three different watery stage, the physical property changes and flow rule of complex fault block in middle-high water cut were studied, using fractal dimension to express pore structure parameters, the subsection regression method was used to analyze the difference between macropore and fine pore, the curves of water cut-water saturation, water cut-displacement effi- ciency, water cut-dimensionless fluid（oil） productivity index were drawed. The results showed that the porosity and permeability increased along with the flood water, the increase scope of inspissated pool was more, rock water affin- ity enhanced, fractal dimension of macropore and fine pore decreased, the heterogeneity was weaken; with the in- crease of water cut, the displacement efficiency heightened, but the increase scope flattened in the high water cut stage; dimensionless oil productivity index dropped with the water cut increase, in the high water cut stage, dimensionless oil productivity index of inspissated pool dropped sharply, but the dimensionless oil productivity index of thin oil was immobile, dimensionless fluid productivity index rised sharply, water drive was into the flushed production period, thin oil reservoir reservoir was suit to enhanced liquid overall, heavy oil was suit to enhanced liquid before water cut 80%.