Application of NPI Decline to Gas-injection Transient Analysis

摘要

According to no theory nor software for gas-injection transient analysis published yet, the equation for gas injection seepage was solved to obtain NPI decline curves for gas-injection on the basis of modified material balance time. Production data were handled by use of calculator programs in Matlab to acquire drainaged parameters for gas-injection through typicalcurves fitting, which has the feature to forecast gas-injection performance in the future using the results of gas-injection analysis eventually. Calculation of C21well production data using the method above shows that the drainage parameters for gas-injection close to that from Well Testing, and the forecasted production performance is in line with the real injection data, which prove the method above valid in analyzing gas-injection effectively. The result above provides a new tool for gas-injection transient analysis.