A Simplified Method for Determining Gas-Well Deliverability

Abstract

Summary This paper presents a simplified method for predicting the performance of a gas well. A method for determining the deliverability of an unfractured gas well by use of a single-point flow test and a dimensionless Vogel-type inflow performance curve was proposed by Mishra and Caudle. Their procedure necessitates the calculation of real-gas pseudopressures for shut-in and flowing bottomhole pressures (BHP) obtained from pressure-buildup and stabilized-flow tests, respectively. This paper offers a simplification of this technique in which a range of pressure values is defined over which pressure-squared terms can be substituted for pseudopressures. A comparison is made between results obtained from analysis of well-test data on several gas wells made with conventional multipoint test methods, with the Mishra-Caudle technique, and with the simplified method presented in this paper. The simplified method offers the engineer who might not have access to a pseudopressure computer program or pseudopressure tables a method for estimating gas-well deliverabilities. The method of Mishra and Caudle and the simplified method were both observed to yield slightly conservative estimates of gas-well deliverabilities compared with the deliverabilities calculated from multipoint flow-test analyses. The simplified technique was found to be useful for predicting the performance of fractured gas wells as well as unfractured wells.