Material Balance Method For Abnormal High Pressure Gas Reservoir

In recent years, with the deepening of exploration and development, abnormal high pressure gas reservoir is more and more important, physical parameters of abnormal high pressure gas reservoir change complicated, different from the normal pressure gas reservoir. This article mainly aims at the production data analysis method of abnormal high pressure gas reservoir. The article analyzes three kinds of production data analysis method for abnormal high pressure gas reservoir, the three methods are based on the material balance theory, R-F material balance method for abnormal high pressure gas reservoir, the flowing material balance method, the dynamic material balance method.The research finds that in the development of the abnormal high pressure gas reservoir, the compressibility of rocks and formation water should not be neglected. So the paper researches the use of R-F material balance method in abnormal high pressure gas reservoir, and analyzes the factors which affecting its production. The conclusion is: the increase of formation rock compressibility leads to the increase of production, and the decrease of the formation rock compressibility leads to the decrease of production. The compressibility of formation water has little effect on the production of abnormal high pressure gas reservoir. In the late stage of gas reservoir exploration, the increase of gas compressibility leads to the increase of the production of abnormal high pressure gas reservoir and the decrease of gas compressibility leads to the decrease of the production of abnormal high pressure gas reservoir.Next, this paper studies the flowing material balance method, and analyzes the feasibility of predicting gas reservoir production. The flowing material balance method do not need well shut-in, only need to use daily gas production and flowing pressure data to predict production. This paper deduces the flowing material balance equation based on the conventional material balance equation. The study shows that the theoretical foundation of the flowing material balance method in gas reservoir is invalid. Programming of the gas mode material balance relation curve for average formation pressure and flowing pressure is not parallel. But programming of the liquid mode material balance relation curve for average formation pressure and flowing pressure is parallel. We can get the conclusion that the flowing material balance method is appropriate for oil reservoir. So flowing material balance method is not applicable to the gas reservoir.At the end of the paper studys the dynamic material balance method. The main advantage of dynamic material balance method is the introduction of the material balance time. It is available in both constant rate and variable flow rate. Also, it can use flowing pressure data directly to get more accurate results of the single well production without randomness. The dynamic material balance equation is derived based on conventional material balance equation, through practical calculation, the paper forecasts the production of abnormal high pressure gas reservoir. The results show that the accuracy of this method is higher and it is suitable for the abnormal high pressure gas reservoir.