A brief review of the various methods of testing gas wells and examples of their interpretation is presented.
Gas wells are tested for several different reasons. Among these are tests to satisfy the requirements of State Regulatory Agencies, both for the initial test period and periodic testing for use in gas allocation formulas. Tests are made to determine present and future deliverability. Wells are tested to meet the requirements of pipe line companies as to contract specifications of deliverability, line pressure, volume, and quality of gas. Tests are also run to evaluate the efficiency of completion and to determine if the deliverability of the well can be permanently improved by various stimulation procedures.
One important objective is obtaining adequate physical tests to correctly select the production equipment in order that the maximum profit may be obtained from the gas supply and that delivery of gas can be maintained during severe weather conditions.
Well tests are used for the very important purpose of determining gas reserves. The two testing procedures which can be used to determine reserves are the "Reservoir Limit Test", which is a determination of the minimum amount of gas connected to the well from its drawdown characteristics, and the periodic measurements of bottom hole pressure plotted against the corresponding cumulative gas production. This data is used to supplement the reserve estimates made by the pore volume or volumetric method.
