Deployment and Exploration of a Gas Storage Well Pattern Based on the Threshold Radius

To tackle the problem that wells that are deployed in a specific pattern based on the requirements of gas reservoir development are not suitable for gas storage, we have conducted concentrically circular injection and production simulation experiments for gas storage, discovered the existence of a threshold radius, denoted by R-t, and derived the expression for R-t. Based on the analysis and discussion results, we propose a strategy for deploying gas storage wells in specific patterns. The expression for R-t shows that it is affected by factors such as the gas storage gas production/injection time, the upper pressure limit, the lower pressure limit, the bottomhole flow pressure at the ends of injection and production, the and permeability. The analysis and discussion results show that the R-t of a gas storage facility is much smaller than the R-t for gas reservoir development. In the gas storage facilities in China, the R-t for gas production is less than the R-t for the gas injection, and R-t increases with the difference in the operating pressure and with permeability K. Based on the characteristics of R-t, we propose three suggestions for gas storage well pattern deployment: (1) calculate R-t according to the designed functions of the gas storage facility and deploy the well pattern according to R-t; (2) deploy sparser, large-wellbore patterns in high-permeability areas and denser, small-wellbore patterns in high-permeability areas; and (3) achieve the gas injection well pattern by new drilling, and the gas production well pattern through a combination of the gas injection well pattern and old wells. By assessing a gas storage facility with a perfect well pattern after a number of adjustments, we found that the R-t of the 12 wells calculated in this paper is basically close to the corresponding actual radius, which validates our method. The results of this study provide a methodological basis for well pattern deployment in new gas storage construction.