致密砂岩毛管力曲线计算相渗的分形维数方法

CALCULATING METHOD OF THE FRACTAL DIMENSIONS OF THE RELATIVE PERMEABILITY BY THE CAPILLARY PRESSURE CURVE OF THE TIGHT SANDSTONE

致密砂岩相渗曲线在模拟致密油形成,以及油气田勘探开发中具有重要作用,而由于渗透率极低难以实验测得。为此,利用致密砂岩岩心压汞数据,通过分形理论并经过归一化和非标准化计算得到典型致密砂岩油驱水相渗曲线。研究表明:致密砂岩岩心lgpc与lgS线性拟合程度高,具有很好的分形性质,分形维数分布在2.536~2.734;得到的相渗曲线束缚水饱和度高达70%,两相流动区窄,总有效渗透率低,表明两相渗流情况复杂;计算的相渗曲线与实验测得的油驱水的相渗曲线比较接近,所以可用于致密油运移和聚集过程的数值模拟研究。研究成果为高效开发致密油气藏提供了重要理论基础。

The relative permeability curves of the tight sandstone derived from the simulation of the tight oil possess significant impacts in the exploration and development of the oil and gas field. However,it is fairly difficult to obtain for the permeability is extremely lower. Therefore with the help of the mercury penetration data of the tight sandstone cores and fractal theory,through normalizing and non-standardizing computations,the typical relative permeability curves were achieved for the oil-flooded tight sandstones by the water. The research shows that the linear match between the lgpc-lgS is pretty higher for the tight sandstone cores and moreover the fractal property is greatly better,the fractal number is between 2. 536-2. 734. The obtained connate water saturation derived from the relative permeability curves can reach as high as 70%,the two-phase flow area is narrow and the total effective permeability is rather lower,these mean that the two-phase flow is very complicated. Compared with the actually measured oil-flooded relative permeability curves,the calculated ones are pretty closer,therefore all the achievements can be adopted in the numerical simulation study of the migration and accumulation of the tight oil,so theimportant theoretical foundation has been presented for the high-efficiency development of the tight oil and gas reservoir.