Pressure-transient analysis of infinite-conductivity fractured gas wells producing at high-flow rates

It is commonly observed in field practice that hydraulically fractured wells perform as though the effective fracture half-length and fracture conductivity were much less than the designed parameters. This observation keeps on creating conflicts and dilemmas between the well stimulation and production engineers. It is widely accepted in the field that part of this controversy is due to high-velocity flow in the fracture around the wellbore, which restrains the flow of gas toward the wellbore and deteriorates the overall well performance. Thus, proper diagnosis of the post-fracture well test and good estimation of the fracture parameters are crucial for accurate stimulation treatment assessment, production forecast, and recovery calculation.This paper presents for the first time a technique that analyzes high-flow rate drawdown data of infinite-conductivity fractured gas wells producing at constant-sandface pressure. This technique will enable the well test analyst accurately calculating the fracture half-length and non-Darcy flow coefficient from a single well test. The proposed method is based on a new semi-analytical equation that integrates the effects of high-velocity flow in the fracture. A comprehensive inspection of the diverse factors affecting the flow behavior of real-gas in the fracture and reservoir in the vicinity of the wellbore is demonstrated. Moreover, a step-by-step procedure illustrating the application of the proposed method using simulated well tests is also presented.