Abnormally High Pressure Gas Reservoir Prediction Methods And Applications

Overpressured gas reservoir being a kind of special gas reservoir, can be found all over the world, whose pressure gradient is greater than 0.02MPa/m, or pressure coefficient is generally greater than 1.2 and over 1.5. Compared to normal pressure gas reservoir, expulsion mechanism of Overpressured gas reservoir is complicated. Performance of Overpressured gas reservoir is not only affected by gaseous elastic energy and periphery aquifer encroachment energy, but also by the three incident sublevel expulsion mechanism. Therefore, performance prediction of Overpressured gas reservoir is greatly different from that of normal pressure gas reservoir.Based on the studies of a great number of literatures, this paper start with Overpressured gas reservoir' s genesis and basic feature, and probe its influence on the hydrocarbon reservoir formation, conservation, exploratory development in detail, and present that both porosity stress sensibility and permeability stress sensibility have potential impact on performance history of gas reservoir. After comparing several calculation reserves methods of Overpressured gas reservoir, put up with the calculation reserves analytical methods which are suitable for constant volume Overpressured gas reservoir and waterflood Overpressured gas reservoir. In addition, this paper deduce identification method suitable for Overpressured gas reservoir waterflood by means of that of normal pressure gas reservoir.Through the theoretical investigation, get the idea that the influence of variable formation compression coefficient on pressure drop and the influence of permeability sensibility on gas-well deliverability is non-negligible. Hence, this paper set up material balance equation and performance prediction model of constant volume and waterflood Overpressured gas reservoir, and establish performance prediction application program of Overpressured gas reservoir using Visual Basic.In the end, verify performance prediction model of Overpressured gas reservoir using the application program, predicate gas reservoir performance under the conditions of different formation compression coefficient, contrast and analyze the rule of production-index of gas reservoir changing with time, prove that the model consider different kinds of factors which impact gas reservoir development and suitable for performance prediction of practical...