A Semi-Analytical Model for Gas–Water Two-Phase Productivity Prediction of Carbonate Gas Reservoirs

The productivity prediction of gas wells in carbonate reservoirs is greatly affected by the characteristics gas–water two-phase flow and fracture seepage parameters. Compared with numerical simulation, based on analytical model fast widely used, but traditional fairly simplified while dealing nonlinear problem equation, leading to a large discrepancy results dynamic analysis. To solve this problem, paper considers reservoir fracture, uses dual-medium characterize stress sensitivity reservoir, establishes for reservoirs. Combining flowing material balance equation Newton iteration method, parameters percolation are updated step use average formation pressure, linearized through successive iterations obtain semi-analytical solution model. accuracy was verified using comparison commercial simulation software field application, curve obtained, influence sensitive analyzed. show that: (1) method can efficiently deal rapidly (2) water production seriously affects wells. During development process, pressure difference should be reasonably controlled reduce negative impact performance.