松南火山岩气藏流体相态特征研究

松南火山岩气藏流体CO2 含量高，相态变化复杂，特别是近临界区域密度、黏度随温度压力的变化不同于常 规烃类气体，因此，进行了高含CO2 气藏流体相态研究。开展了高含CO2 流体高压物性实验，观测了不同温度压力下 不同CO2 流体的高压物性参数，并观察到在低温条件下高含CO2 流体的近临界现象。在PVT 实验的基础上，分析了 不同CO2 流体的偏差因子、体积系数随压力温度的变化关系。针对含CO2 体系的近临界特征，修正高含CO2 体系状 态方程，分析了近临界区域密度、黏度的变化规律，解释了实验观测中的近临界现象。应用修正高含CO2 体系状态方 程绘制p ? T 相图，可对松南气田开采及生产过程中的流体相态特征进行判断。

Research on Phase Behavior of High CO2 Fluid of Songnan#br# Volcanic Reservoir

Songnan volcanic gas reservoir has high concentration of CO2 and the phase behavior is very complex. In the near critical region，the phase change trend，such as density and viscosity over temperature，is different from that of common hydrocarbon gas. The abnormal phase change may influence the development of gas field，and even create the production accidents. Thus，it is necessary to carry out research on high CO2 fluid of Songnan gas reservoir. Firstly，a series of PVT experiments of high CO2 fluid were conducted. PVT parameters of fluid with different CO2concentration were detected and calculated. Then，in order to analyze the near-critical character of CO2 fluid，the EOS for fluid with high concentration of CO2 was modified. Finally，p ? T phase graph of fluid with CO2 concentration was drawn，which provided the foundation for the judgment of the phase behavior of Songnan gas field.