Subsidence Mechanisms and Exploration and Development in Deepwater Gas Reservoirs: Advances and Perspectives.

Deepwater gas has emerged as a critical domain for global natural gas reserve growth, production enhancement, and supply replacement; yet its long-term development is constrained by production-induced compaction and subsidence. Reservoir compaction, overburden deformation, and seabed subsidence induced by deepwater gas production constitute a complex, coupled, multiphysics geomechanical problem involving three fundamental mechanical issues: identifying the dominant mechanisms governing time-dependent reservoir deformation, establishing constitutive frameworks for compaction and subsidence with clear applicability boundaries, and developing coupled, multiphysics geomechanical numerical methods for complex deepwater stratigraphic settings. This paper provides an integrated overview of the distribution patterns of deepwater gas reservoirs and the progress in exploration and development worldwide and in China. Specifically, the latest progress is reviewed and discussed in terms of five aspects: compaction and subsidence mechanisms in deepwater gas reservoirs, subsidence monitoring systems for deepwater environments, key controlling and influencing factors of production-induced subsidence, characteristics of constitutive models for compaction and subsidence, and coupled multiphysics numerical approaches. By linking these topics to engineering practice, this review aims to provide a systematic reference for subsidence risk identification, monitoring scheme design, and predictive decision-making in deepwater gas fields.