Techno-Economic Evaluation of Multi-Well Production in Gas Hydrate Deposits: Impact of Boundary Layer Permeability

The permeability of boundary layers in gas hydrate deposits is a critical factor influencing production performance, yet its impact has not been fully evaluated from a techno-economic perspective. This study developed a “reservoir simulation + cash flow analysis” evaluation framework to address this gap. Specifically, field-scale production simulations were performed to obtain gas-water production data under open- and closed-boundary conditions. A net present value (NPV) model incorporating a comprehensive range of costs, including drilling, production, operation, and maintenance, was then developed to calculate key economic indicators. The results demonstrate that development under open-boundary conditions is economically unviable, even at a high gas price of 5.4 RMB/m3, as the low gas revenues could not offset the substantial lifting energy expenditures, which represent the primary cost component. In contrast, development under closed-boundary conditions yields positive NPVs (21.8–124.1 million RMB), with a payback period of 3–7 years, an internal rate of return of 17.3–53.9%, and an allowable investment in boundary sealing of 20–85 million RMB. Additionally, increasing well spacing and reducing production pressure are identified as effective in enhancing economic performance; the optimal strategy for field development is the combination of well spacing > 150 m and production pressure < 3 MPa.