PRESSURE TRANSIENT ANALYSIS IN GAS RESERVOIRS (PSEUDOPRESSURE APPROACH - A NEW APPROACH)

The ability to analyse the performance and forecast the production of gas wells is important in gas reservoir engineering. Information like the reservoir permeability, damage and improvement, reservoir pressure etc should not be faulty because when faulty, estimation of information that involved them will also be faulty which will in turn depicts wrong forecast of the gas well. To obtain a reasonable degree of accuracy, different analytical methods have been studied and applied to modern gas well testing. Many of them were developed with the intent of linearizing the nonlinear gas flow equation.

In this thesis, the non-linear gas diffusivity equation was almost linearize using the single phase pseudopressure. And with its solution and a modified single phase pseudopressure, the gas reservoir was analysed. The transient state flow equation generated serves as the basis for flow test and build-up test analysis techniques for gas well to provide reliable information about the reservoir.

Existing methods were assumed to be accurate and treated as “true data” and were used to provide a “benchmark” to evaluate the accuracy of the proposed method. Various flow and build-up test data were analysed to study the validity of the proposed method. For each analysis, information derived from the proposed method were compared with that of existing method. Some conclusions were drawn on the basis of these analyses.