An innovative experimental apparatus for the analysis of sand production during natural gas hydrate exploitation.

Natural gas hydrate (NGH) will become a significant potential energy source in the post-oil era due to its large reserves, wide distribution, high energy density, and low pollution. Sand production is one of the main problems that cause the impossible long-term production of NGH. This paper presents an experimental apparatus that was developed to synthesize NGH and hydrate-bearing sediments and was applied to analyze the sand production and sand control mechanism during hydrate exploitation. The sand production and sand control tests of NGH can be conducted over a temperature range varying from 253.15 to 323.15 K and the maximum chamber pressure and overlying pressure up to 30 MPa. This apparatus is mainly composed of the simulated sand production system, the temperature and pressure control system, and the measurement control system. The simulated sand production system consists of a movable overlying pressure loader, a strain sensor, a simulated reservoir chamber, a sand control system, and a sand production monitoring system. A visual gas-liquid-solid separation tank is applied to observe the gas, water, and sand production. The basic principles of this apparatus are discussed, and a series of experiments were performed to verify that sand production and sand control can be practically applied in the exploitation of NGH reservoirs.