Numerical model and program development of TWH salt cavern construction for UGS

Abstract

Underground TWH caverns in salt rock have high construction efficiency and large usable volumes and provides an ideal space for large-scale natural gas storage. In this study, the solution mining process of TWH cavern is thoroughly analyzed. Applying basic principles of the Navier-Stokes equation method and reasonable assumptions, we established a new 3D mathematical model which includes flow and mass transfer and boundary movement for TWH salt cavern construction. Then, the velocity field and the concentration field can be solved by the SIMPLE algorithm, while the boundary movement of cavern expansion can be solved by the VOF algorithm. We developed a new VC++ computer code program TWHSMC for solution mining and herein we present the numerical results. Finally, the simulation cavern shapes results by program are compared with the experimental ones. The results indicate that our model successfully and accurately predicts the cavern shape and demonstrates the reliability and applicability of the model.

The influence of the water injection method on two-well-horizontal salt cavern construction

“…When using the SWV or TWV methods to construct a cavern, the span limit and height limit pose a great influence on cavern volumes. Therefore, a new salt cavern storage construction method, applying water solution mining with the TWH cavern method has been proposed [4,[12][13][14].…”

“…Based on a VC++ computer program (TWHSMC V2.0) [4], this paper conducts simulations under different water injection methods to investigate brine concentration changes, the construction rate, and the development of the cavern geometry. The simulation results reveal the influence of the water injection method and provide theoretical constraints for TWH salt cavern storage construction.…”

“…Underground large-scale energy (CNG and CAES) storage is widely used in industrial gas grids [1,2]. It acts as a buffer to balance out temporal differences between the production and consumption of gas, and has been successfully employed around the world for many decades [3,4]. It is a key element of the present natural gas infrastructure worldwide.…”

An Analytical Solution for Transient Productivity Prediction of Multi-Fractured Horizontal Wells in Tight Gas Reservoirs Considering Nonlinear Porous Flow Mechanisms

“…Because of its strong heterogeneity, complicated microscopic pore structure, and poor connectivity of the effective sand bodies, the porous flow mechanism of tight gas reservoirs is obviously distinct from those of conventional reservoirs. Moreover, because of poor reservoir physical properties, small discharging radius, lack of or low natural productivity, high development difficulty, and some other potential disadvantages, a MFHW with hydraulic stimulations is extensively used for developing tight gas reservoirs [7][8][9][10][11][12][13][14][15][16].To date, many scholars are dedicated to the transient productivity of fractured wells in unconventional hydrocarbon reservoirs, considering the different characteristics of nonlinear flows compared to multi-scale flows. The methods to calculate the transient productivity of fractured horizontal wells primarily include analytical and numerical solutions, among which the analytical solution includes the complex potential theory, conformal transformation, and the equivalent flow resistance method [14,17,18].…”

“…Because of its strong heterogeneity, complicated microscopic pore structure, and poor connectivity of the effective sand bodies, the porous flow mechanism of tight gas reservoirs is obviously distinct from those of conventional reservoirs. Moreover, because of poor reservoir physical properties, small discharging radius, lack of or low natural productivity, high development difficulty, and some other potential disadvantages, a MFHW with hydraulic stimulations is extensively used for developing tight gas reservoirs [7][8][9][10][11][12][13][14][15][16].…”