Effect of sand production on physical properties and fracturing development of gas hydrate reservoir

Abstract

Offshore gas hydrates are being focused on as an unconventional energy source. The susceptibility of marine hydrate reservoirs to sand emergence makes them unsuitable for long-term exploitation. This research delves into the particle-transport law in hydrate reservoirs, revealing that sand blockage hinders long-term exploitation, and proposes a reservoir modification strategy to establish high-permeability channels, thereby enhancing production. After 110 days of mining, the range of porosity and permeability below the initial value was approximately 8.5 m. The study further optimizes reservoir modification parameters under sand blockage, suggesting that a balance between fracture and reservoir blockage can be achieved with a fracture half-length of 20 m, leading to increased production. It also highlights that the slow decomposition of blocked hydrate and the accumulation of decomposed methane gas in the upper part of the reservoir can be leveraged to increase production by providing a high permeability channel for free gas, concluding that maintaining long-term high permeability is crucial for hydrate reservoir fractures.