川东北地区天然气偏差系数计算方法评价

天然气偏差系数是气藏储量计算中一项非常重要的基础数据，可通过高压物性PVT 实测取得，也可以通过计算方法计算求得。针对在川东北地区各计算方法的适用条件及计算精度不是特别明确的问题，开展了各种计算方法的评价研究，研究中利用4 种常用计算方法的预测结果分别与Standing–Katz 天然气偏差系数图版中不同拟对比压力及拟对比温度下对应的偏差系数及川东北地区实测天然气偏差系数对比分析及评价，获得各种计算方法的适用范围；认为DAK 及DPR 方法实用范围较宽，有较高的计算精度，适用于川东北地区高温高压条件天然气偏差系数的计算。

The Comprehensive Evaluation of the Deviation Factor Calculation of Natural Gas in Northeast Sichuan

Natural gas deviation factor is one kind of important data that can be obtained through PVT experiment or calculationmethods. Because the applicable conditions and accuracy of its calculation methods are not particularly clear in NortheastSichuan，evaluation is carried out to study the various calculation methods. Based on the comparative analysis and evaluationon the predictions with four kinds of common calculation methods，deviation factor z-value in Standing-Katz chart underpseudo-reduced pressure and temperature and the measured z-value of natural gas deviation factor in Northeast Sichuan，thescope of various calculation methods is proposed. It is pointed out that both DAK and DPR methods have wide practical scopeand higher accuracy，besides，they are applicable to calculate the deviation factor of gas reserves under high temperature andhigh pressure in northeast Sichuan.