Characteristics analysis of hydrate reservoirs with different geological structures developed by vertical well depressurization

It is one of the most feasible ways for the development of gas hydrate by vertical well and depressurization. In order to compare and analyze the characteristics and performance of gas hydrate with different geological structures developed by vertical well and depressurization, a hydrate development geological model based on Tough + Hydrate is established. The laws of gas and water production in the long-term development are studied. The analysis shows that the initial gas production rate of Class I hydrate is high, and then decreases. The cumulative gas production is significantly higher than that of other types of hydrate. It has the characteristics of high cumulative gas production and low water production. Good economic benefits can be obtained by depressurization production in vertical wells. The gas production rate of Class II hydrate and Class III hydrate increases first and then decreases. The production capacity is lower than that of Class I hydrate. Class II hydrate has serious water production problem, and its production capacity is the lowest. Therefore, Class II gas hydrate needs to solve the problem of water production. Class III gas hydrate can release production capacity through well pattern optimization or increasing reservoir contact area.