复杂裂缝网络系统油水相渗曲线特征实验研究

Experimental Researches on Relative Permeability Curve of Complex Fracture System

裂缝系统油水相对渗透率曲线的研究对指导裂缝性碳酸盐岩油藏注水开发起至关重要的作用。以实际裂缝性碳酸盐岩油藏储层地质特征为基础,设计并制作了裂缝系统逐渐由简单到复杂状态的多组大尺寸裂缝型渗流物理模型。参照行业标准,采用非稳态法水驱油相渗实验测试方法,研究了裂缝系统中不同裂缝宽度与不同缝网结构和缝网密度对油水相对渗透率曲线形态的影响。结果表明,裂缝系统平均裂缝宽度越大,油水相渗曲线形态越向交叉斜直线形态靠近,两相共渗区范围越大;缝网密度越大,结构越复杂,相渗曲线中的束缚水饱和度就越大,两相共渗区范围就越小,等渗点位置则逐渐向右移动。

Oil-water relative permeability curve of fracture system is very important in the waterflooding process of naturally fractured reservoirs. We designed and made a series of large size physical model of fracture system based on the geological charac- teristics of a certain fractured carbonate reservoir. Oil-water relative permeability curves were measured by using unsteady-state method. The influence of fracture density and average fracture aperture on oil-water relative permeability curves was studied. The results show that the shape of relative permeability curve is close to X curve type, and common percolation area of two phases turns wide. When the irreducible water saturation increases, the common percolation area of two phases reduces with the fracture density growing. With greater fracture density, the structure becomes more complex, the irreducible water saturation in the phase permeability curve greater, and the range of the two-phase percolation area smaller, and the position of the seepage point gradually moves to the right.