一种计算平均毛管压力曲线的方法

A METHOD FOR DETERMINING AVERAGE CAPILLARY PRESSURE CURVE.

根据Brooks R H和Corey A T建立的毛管压力同阈压之比(P_c/P_e)与有效湿相饱和度S_(wt)之间的统计公式提出一种计算平均毛管压力曲线的方法.该方法经夏子街油田压汞毛管压力曲线数据验算,曲线形态良好.与传统方法相比,方法简便,计算精度高,易于在微机上实现.该方法同时给出平均毛管压力曲线的数学表达式及其孔隙度大小分布指数λ,这对扩大毛管压力曲线的应用很有意义.

According to the statistics formula between the ratio of capillary pressure to threshold pressure (Pc/Pe) and the effective wetting-phase saturation(S*wt) established by Brooks R.H. and Corey A.T., the method for determining average capillary pressure curve is presented in this paper. It is checked with the data of mercury-injection capillary pressure of Xiazijie oilfield and the shape of curve is satisfactory. As compared with that of the tradtional J-function, this method is simple, convenient, high-precision and easy to operate on PC. Meanwhile, a mathmatical expression for average capillary pressure curve and porosity size distribution exponent A also put forward. It is of great significance to extend the application of capillary pressure curve.