GAS WELLS DELIVERABILITY DETERMINATION USING FLOW-AFTER-FLOW TEST ANALYSIS
Gas properties vary significantly with pressure change. To take this variation in gas properties into account the Pseudo pressure has to be used instead of pressure in all calculations. This paper presents an analysis of Flow-after-flow test for gas wells. The analysis has been performed through using the Simplified method and Laminar-Inertial Turbulent (LIT) Approach, which includes Pressure, Pressure squared and Pseudo-pressure methods. Wetherford PS software has also been used to analyze the test. IPR curve for a gas well has been constructed by using both C,n and LIT methods and the results have been compared with the results obtained from PS software. To check the applicability of each approach, all results have been compared with Pseudo-pressure method as it is superior to all other methods. AOFP has been determined for all methods. The results have revealed that Pseudo pressure method, manual Simplified and pressure squared under estimate AOFP whereas pressure method over estimate it. On the other hand, PS software results for AOFP from both simplified and LIT method are reasonably close as the software uses pseudo pressure for both methods.