Evaluation Method and Analysis of Influencing Factors for Productivity of Ultra Deep and High Pressure Gas Wells

Due to the high temperature and pressure, as well as the development of multi-scale pores and fractures, the development of ultra deep gas reservoirs faces a series of challenges such as complex reservoir seepage laws and special development laws. The Qixia Formation of SYS gas reservoir is difficult to conduct downhole pressure testing due to the small wellbore size and high pressure of ultra-deep gas well, resulting in inaccurate gas well productivity testing. We have established a productivity prediction model that considers multiple factors such as stress sensitivity and high-speed non Darcy, and analyzed the impact on productivity. We have also established a productivity prediction chart to provide a basis for subsequent gas reservoir development and production allocation. The results indicate that using a productivity prediction model to analyze the impact of single factors on gas well productivity, it is clear that permeability, reservoir thickness, and reservoir type have a significant impact on gas well productivity. Based on the results of single factor production capacity analysis, a production capacity prediction chart was established to predict the open flow rate of SY001-1 well to be 136 × 104 m3/d, with a calculation error of <10%.