Study on Sand Control Technology for Exploitation of Shallow Oozy Silt Hydrate Reservoirs at Sea Areas

Sand production in the process of natural gas hydrate production is one of the major factors affecting the safe and long-term exploitation of gas hydrate. Once sand control fails, the hydrate production would be forced to stop. Sand production in marine gas hydrate exploitation is caused by multiple factors and is accompanied by complex coupling of these factors, making it more difficult to control than in conventional oil and gas wells in loose sand reservoirs. The study of sand production mechanisms in and sand control technology for gas hydrate reservoirs needs to think out of the box of the idea for traditional oil and gas reservoirs and should start from the coupling of hydrate and reservoir multi-fields. Current experiences of hydrate production tests at sea areas show that it is impossible to solve special situations of sand production in different periods before, during and after hydrate decomposition and possible secondary production by single sand control technology. The composite sand control technology of reservoir stimulation + wellbore stability + sand control can effectively deal with the difficulties that may occur in the depressurization production process, such as sand production, mud and sand plugging, and wellbore instability etc.