Abnormally High Pressure Gas Reservoir Prediction Methods Research

Overpressured gas field, being a kind of special gas field, can be found all over the world, whose pressure coefficient is generally greater than 1.0 and over 1.5. Therefore, in the course of performance prediction of overpressured gas field, it can not be used to estimate the gas field's Original-Gas-In-Place and predict the production's index during of the stable production period and the production decline period until the basic forecast model of corresponding material balance equation must be modified and improved.On the base of the studies and analyses on a great number of related reference, this paper start with the forming of overpressure and its influence on the hydrocarbon reservoir formation, conservation, exploration and exploitation of gas reservoir. And it thoroughly makes a study of the different treating of the property parameters of overpressured gas field and normal pressured gas field. In sufficient consideration of the basic geologic characteristic of overpressured gas field, the mathematical model of the performance prediction of overpressured gas field has been established. And with the study of the different estimation methods of the Original-Gas-In-Place of overpressured gas field, the performance prediction of production has been made respectively in the stable production period and the production decline period. At the end of this paper, the performance prediction program of overpressured gas field has been developed with VB. And with this program, the detailed performance prediction has been conducted on the actual overpressured gas field. The calculation results show that the methods presented in this paper are correct and reliable.