Commercial production potential evaluation of injection-production mode for CH-Bk hydrate reservoir and investigation of its stimulated potential by fracture network

Abstract In this study, the productivity of depressurisation combined with thermal stimulation using the injection-production mode (D + Ti) in a CH-Bk reservoir (a natural gas hydrate reservoir exhibiting a low permeability and lack of impermeable boundaries) was explored. By exploring the influence of production parameters and well patterns on hydrate development, the challenges faced in the development of D + Ti and its commercial production potential were explored. Furthermore, the stimulation potential of the fracture network on D + Ti was investigated. The results showed that the interlayer contradiction and the low methane flow capacity between the injection-production well led to poor production ability and insensitivity to production parameters for D + Ti. The permeable caprocks limited the well pattern infilling potential of D + Ti. These defects made it impossible for D + Ti to obtain commercial production in the CH-Bk reservoir. The fracture network significantly improved the productivity and well pattern infilling potential of D + Ti. In particular, the gas production rate and production degree of the five-spot well increased by 6.5 and 7 times, respectively, after network fracturing, reaching commercial standards. Thus, D + Ti combined with network fracturing can be a promising mode for CH-Bk development. This study can provide meaningful guidance for future CH-Bk trial production and commercial development.