Abstract

The accuracy of dynamic reserve calculation in gas fields is of significant importance for the rational and efficient development of oil and gas fields, as well as the establishment of gas well production allocation schemes. The reservoir in the ZT block in the northwest of Sichuan is tight and highly heterogeneous, with complex gas-water distribution and significant differences in gas well test production rates and rapid decline rates. In order to accurately calculate the dynamic reserves of such tight water-bearing gas wells, this study focuses on the tight water-bearing gas reservoirs in the ZT block in the northwestern region of Sichuan. Rock core X-ray diffraction experiments, constant rate mercury injection experiments, and reservoir rock stress sensitivity experiments were conducted. Based on the experimental results, corrections were made to the porosity and permeability of rock samples under effective stress conditions using a binary linear regression method. These corrected parameters were then incorporated into the water-sealed gas material balance method, establishing a new method for calculating dynamic reserves in water-bearing tight gas reservoirs under stress-sensitive conditions. Utilizing reservoir parameters and production data from the ZT block, the results of the material balance method, well testing analysis method, and mathematical statistical method were compared with the results obtained using the new method. The dynamic reserve calculations for water-bearing tight gas reservoirs considering stress-sensitive conditions showed smaller relative errors and more accurate results.