天然气水合物生成条件预测模型的比较

天然气水合物理论预测模型是在Van der Waals-Platteeuw模型的基础上发展起来的。目前,预测天然气水合物形成条件的模型有8种,即两种经验或半经验模型(KK和回归公式)和6种热力学相态平衡理论模型,采用这8种模型对给定压力下水合物的形成温度进行了计算,与实测值相比,计算值都偏小。在低压下(压力小于5MPa)时计算值相差不大,误差较小;但当压力大于5 MPa后,计算值相差较大。其中采用两种经验或半经验模型(KK和回归公式)计算给定压力下水合物的形成温度时,计算值偏低。而6种热力学相态平衡理论模型计算误差较小,误差大小顺序为VDW>PP>HJ>NR>Du＆Guo88>Chen＆Guo96。其中Du＆Guo88和Chen＆Guo96两种模型计算最精确。

THE PREDICTION MODEL COMPARISON OF GAS HYDRATE FORMATION CONDITIONS，OGST

Structures of hydrate have I, II and H structure. At present, the theoretical models are based on Van der Walls model. Gas Hydrate Formation Conditions prediction models have two empirical or semi-empirical correlation models and 6 thermodynamics phase equilibrium models. The 8 models are adopted to calculate gas hydrate formation temperatures on given pressures condition. All calculating temperature values are lower than field data. Calculating errors are little with field data while pressures are below 5 MPa. But calculating errors are great with field data while pressures are above 5 MPa. 6 thermodynamics phase equilibrium models calculating errors are in turn : VDW >PP>HJ > NR> Duo &. Guo88>Chen & Guo96, namely Duo & Guo88 and Chen & Guo96 are best calculating models for gas hydrate formation conditions prediction.