酸性气藏气体偏差系数计算模型

应用传统经典状态方程计算酸性气藏天然气混合物物性参数会带来较大偏差,以文献［１２］提供的实验室测试数据为基础,采用未校正的DPR模型、HY模型、DAK模型、Sarem模型和HTP模型,以及GXQ校正法和WA校正法,计算了酸性气藏气体偏差系数,并与实验测试值进行对比,评价出酸性气藏气体偏差系数计算模型的适应性。研究结果表明：①酸性气体的偏差系数校正计算模型由于考虑了酸性组分对混合物临界压力和温度的影响,其计算精度普遍高于未校正计算模型;②GXQ校正法是在高压气体混合物规则基础建立的,其计算误差高于WA校正法;③DPR模型和DAK模型结合WA校正方法计算低压酸性混合气体偏差系数较为准确,其次是HY模型,而采用Beggs & Brill模型、Sarem模型和HTP模型误差较大,不适于计算酸性气体的偏差系数。

A CALCULATING MODEL FOR GAS DEVIATION COEFFICIENT OF SOUR GAS RESERVOIRS

The application of traditional classical equation of state to calculate the physical property parameters of gas mixture in sour gas reservoir will bring out relatively great deviation. Therefore, taking the laboratory test data provided by ADEL M. Elsharkawy (see ADEL M Elsharkawy, Predicting the properties of sour gases and condensates: Equations of state and empirical correlations".SPE 74369.prented at the 2002 SPE international petroleum conference and exhibition held in Villaherrmosa, Mexico,2002:10 12) as the foundation, using the uncorrected DPR model, HY model, DAK model, Sarem model and HTP model, as well as the GXQ correction method and the WA correction method, the gas deviation coefficient of sour gas reservoirs has been calculated and compared with experimental test value, and then the adaptability of the calculating model for gas deviation coefficient of sour gas reservoirs has been evaluated. Results show that: ①with the consideration of the influence to critical pressure and temperature of the mixture caused by sour components, the calculating result has a higher calculation accuracy than the uncorrected ones; ②compared with the WA correction method, the GXQ correction method will result in more errors based on high pressure gas mixture rules; ③using the DPR model, the DAK model, combined with the WA correction method, to calculate low pressure sour mixture deviation factor will produce relatively accurate results, and the HY model comes next. However, the models of Beggs &; Brill, Sarem and HTP will cause relatively great errors, which are not suitable for calculating the coefficient deviation of sour gas.