高压超高压天然气偏差系数实用计算模型——LXF高压高精度天然气偏差系数解析模型的修正

PRACTICAL CALCULATING MODEL OF GAS DEVIATION FACTOR WITH HIGH AND SUPER -HIGH PRESSURE 1)

天然气偏差系数是气田开发中非常重要的一个高压物性参数,是气藏储量计算和气藏动态分析中必不可少的基础参数。LXF模型是通过对Standing-Katz图版进行拟合得到的高压和超高压天然气的偏差系数的解析计算模型,但直接利用其模型计算的结果存在着较大的误差,在现场难以得到有效的推广应用。文章利用LXF模型的求解思路,在对Standing-Katz图版和Poettmann-Carpenter的Z函数表进行多项式拟合回归的基础上,重新确立了LXF高压和超高压天然气偏差系数计算模型中的各项系数,修正了原LXF解析计算模型。修正后的LXF模型在保持原LXF模型计算方法快捷、简便的特点的同时,有效地提高了LXF模型的计算精度,有利于气藏工程师的现场应用,也有利于LXF模型能够得到更加有效的推广应用。

The gas deviation factor is a very important parameter of high-pressure physical property (or gas field development, and the indispensable basic parameter for the reserves calculation and the performance analysis of gas reservoirs. LXF model is the calculating analytical model of gas deviation factor with high and super-high pressure derived from fitting Standing-Katz chart board. But the results directly calculated by the model have big errors. It is difficult to use the model in the field practically. With the solution idea of LXF model, based on the polynomial fitting regression of Standing-Katz chart board and Poettmann-Carpenter Z function, the all factors are re-determined for LXF calculating model of gas deviation factor with high and super-high pressure and the original LXF calculating analytical model is corrected. The corrected LXF model effectively improves the calculating accuracy of LXF model as well as keeps the features of fast and easy calculation of the original LXF model. It is favor for reservoir engineers to use in the field. Also, it is favor for LXF model to be expanded and applied effectively.