Impact of Well Interference on Transient Pressure Behavior During Underground Gas Storage: A Comparative Study

Abstract

Underground natural gas storage (UGS) is key to achieving carbon neutrality and it is also a potential solution to the seasonal imbalance between gas supply and demand. To store or withdraw a large amount of natural gas within a specified time, wells in UGS projects often need to have high continuous injection and withdrawal capacities. High injection and withdrawal rates lead to uneven pressure distributions in UGS and substantial well interference. This paper proposes an analytical model to investigate the impact of well interference on transient pressure behavior in UGS wells. We used Laplace transforms and the Stehfest numerical inversion algorithm to obtain an analytical model of the pressure response of a vertical well in a UGS project. We used the superposition principle to model well interference effects, and we used a commercial numerical simulator to validate analytical solutions for different cases. Results show that the pressure behavior during interference depends mainly on the operational status of adjacent wells. When an adjacent well is withdrawing gas, interference causes the pressure derivative to first rise and then flatten later. When gas is injected into the adjacent well, the pressure derivative curve drops continuously and is similar to the shape for a well near a constant pressure boundary. The types of adjacent wells affect the rate of rise of the pressure derivative curve at later times. Interference with a target well is more likely when we inject into or produce gas from a vertical well than from a horizontal well. The application of our methodology is illustrated for the Hutubi UGS. Available data from nine cycles of injection and withdrawal in this UGS project indicate that the cumulative gas injection volume and the gas withdrawal volume were 155.43 × 108 m3 and 130.81 × 108 m3. The final gas storage volume eventually reached 93.5% of the designed UGS capacity.

The injection capacity evaluation of high-pressure water injection in low permeability reservoir: numerical and case study

“…Most of this research relies on well test analysis to explore the changing patterns of bottom hole pressure during high-pressure water injection. All these studies presume that the flow within the reservoir constitutes single-phase flow adhering to Darcy's law (Chu et al, 2023a;Chu et al, 2023b). The effects of threshold pressure gradient and fluid-structure interaction are not considered.…”