油藏流体中H型水合物生成条件的计算

1 INTRODUCTION Gas hydrates are serious problems in the petroleum and petrochemical industries since it may cause the plugging of production facilities and trans- portation pipelines during gas and oil production. It is known to all that gas hydrates have three poten- tial hydrate formation structures: structure- structure- and structure-H (SH). The two for- mer structures have been studied extensively and their phase equilibrium conditions are well characterized. For a long time, molecu…

Prediction of Structure-H Gas Hydrate Formation Conditions for Reservoir Fluids

In this work, a thermodynamic model is developed for prediction of structure H hydrate formation. The model combines the Peng-Robinson equation of state for the vapor, liquid and aqueous phases with the extended Ng-Robinson hydrate model for gas hydrate formation of all three structures. The parameters of 14 structureH hydrate formers are determined based on the experimental data of structure-H hydrates in the literature. The expression of fugacity of water in the empty hydrate phase is correlated for calculating structure-H hydrate formation conditions in the absence of free water. The model is tested by predicting hydrate formation conditions of a number of structure-H hydrate forming systems which are in good agreement with the experimental data. The proposed model is also applied to the prediction of hydrate formation conditions for various reservoir fluids such as natural gas and gas condensate.