A study of the factors which affect the results of short-term multi-rate gas well tests

Abstract

The performance of gas wells as indicated by the Bureau of Mines back-pressure test was evaluated. A gas well in a new reservoir, in a reservoir with prior production history and with a horizontal fracture was investigated. The results showed that the performance indicated by a Bureau of Mines back-pressure test is sensitive to the magnitude of the flow rates, the duration of the flow rates, the initial shut-in time, the shut-in time between flow rates, the magnitude of sequential flow rate increase, fracture length and location, and the reservoir properties involved in the dimensionless time function. Equations which permit the engineer to design a standard back-pressure test so as to eliminate the affect [sic] of testing procedures are presented for non-fractured wells with and without a prior production history. A fitted equation is also presented for estimating the time required to obtain stabilized flow conditions in the formation to surface conductor system.