关键词: 碳酸岩, 压力异常, 气井产能分析, 脉冲阻力, 约束优化, 三项式

Abstract: The TX01 well is the first high-productivity gas well found in the fractured carbonate reservoir formation in the North Slope of the central Ta area. Owing to the special characteristics of the reservoir, it is difficult to insert the pressure gauge down to the middle of the reservoir, resulting in poor quality of pressure data, which consequently affects the accuracy of the production capacity evaluation. Based on previous research on the vertical wellbore pressure of gas-liquid two-phase systems, the abnormal data were screened and the production data were obtained. A method to calculate and calibrate the bottom-hole pressure, with a calculation error of 0.2%, was proposed. Based on the theory of Firoozabadi and Katz, a productivity equation for the high-pressure, high-productivity carbonate gas well, considering the high-velocity pulsed flow of gas at high-productivity, was established. Based on the constraint optimization algorithm, the solution was obtained, and applied to a real case study. The results show that the open flow of this gas well was approximately 10% smaller than the result from the conventional method. The obtained three-term productivity equation and its solution method are more in line with field practice in the study area.

Key words: carbonate rock, pressure anomaly, gas well productivity analysis, pulse resistance, constraint optimization, threeterm equation