Offshore Gas Hydrate Completion Fluid System Construction and Performance Evaluation

Gravel packing is an effective method for preventing sand production during the exploitation of gas hydrate reservoirs. However, the accompanying completion fluid system faces technical challenges, such as secondary hydrate formation and low gravel packing efficiency. Therefore, this paper combines the experience of conventional oil and gas reservoir development in the South China Sea, considers the particularity of gas hydrate reservoirs, constructs different gas hydrate completion fluid systems, and evaluates the complete performance of these systems based on laboratory experiments and numerical simulation techniques. The research results show that commonly used thermodynamic inhibitors such as ethylene glycol and salts require relatively high addition amounts to achieve good inhibition effects, but the higher completion fluid density cannot meet the on-site construction requirements, so kinetic inhibitors need to be used as substitutes. The experimental tests and numerical simulation results show that the completion fluid system formulated with the self-developed SYZ-2 kinetic inhibitor can meet the requirements of various on-site indicators and achieve good completion effects. After comparative analysis, the optimal completion fluid is brine+2.5%PF-HCS+2.0%PF-CA101HT+6.5%NaCl+ 1.0%SYZ-2.