Simultaneous Forecasting of Gas-Oil Ratio and Gas Flow Rates in Near-Critical Gas-Condensate Reservoirs Under Boundary-Dominated Flow Conditions

Summary This paper demonstrates the practicality of forecasting producing gas-oil ratio (GOR) and gas flow rates simultaneously for boundary-dominated gas-condensate reservoir production in contrast to the frequent practice requiring GOR as an input parameter for the forward model. The presented approach adopts an improved saturation-pressure (So-p) relationship—the rescaled constant volume depletion (CVD) method—to enhance the calculation of multiphase pseudopressures, thereby mitigating the potential errors in the forward model predictions. To verify the forecasting accuracy of the proposed method, we provide comparative analyses of concurrent predictions of GOR and gas flow rate implementing state-of-the-art solutions such as Xiao and Al-Muraikhi’s (2004) model, which customarily utilizes the classical CVD approach and requires less straightforward computations. The results obtained from the proposed solution, emphasizing its simplified and fundamentally derived protocol, show significantly better predictive performance, stronger connections to fundamental principles and less empiricism, and noteworthy agreements with numerically simulated case studies, encompassing a broad spectrum of fluid types and bottomhole pressure (BHP) specifications. Therefore, the proposed solution is a straightforward and robust predictive tool for boundary-dominated forecasting of near-critical gas-condensate reservoir production.