根据海底天然气水合物藏特点,结合绞吸式挖泥船工作原理和大洋多金属结核开采技术,提出了一种全新的绞吸式海底天然气水合物开采方法,克服了海底天然气水合物开采依赖构筑封闭开采环境的技术瓶颈;然后根据管道输送原理和两相流理论,对绞吸式开采方法的提升系统进行了水力参数分析.由分析结果可知,将体积浓度为15%～25%天然气水合物流体从1000 m海底提升到海面所需泵的扬程为30～50 m;将体积浓度为10%～20%天然气水合物流体从4 000 m海底提升到海面所需扬程为90～150 m,现有的矿浆泵就能满足要求;由于天然气水合物和海底沉积物硬度较低,并且其混合流体的密度与海水密度相差不大,采用矿浆泵进行直接输送其对泵的磨损不会严重,能保证系统长期稳定的工作,证明了该开采方法在理论上是可行的.%According to the characteristic of submarine gas hydrates and combining the working principle of Cutter Suction Dredger and the exploitation technique of the polymetallic nodule mining in ocean, a new exploitation mode named cutter-suction marine gas hydrate was proposed and used to resolve the technology bottleneck restrict that the gas hydrates under the sea couldn't be exploited without a close exploiting environment. And then based on the pipeline transporting principle and the two-phase flow theory, the hydraulic transmission system was analyzed. The result shows that the hydraulic with volume concentration of 15％ to 25％ pumped upon to the sea-surface from 1 000 m depth only needs deliverylift about 30 m to 50 m, and pumped from 4 000 m with volume concentration of 10％ to 20％ only needs deliverylift about 90 m to 150 m which the common double channel impeller pump present having also can meet the requirements; besides the stiffness of the gas hydrate and the submarine sediment are low, and the density of their compound fluid is similar to the seawater, so the gas hydrate transported directly by slurry pump will not cause the slurry pump wearing badly which can keep the system working stably for a long time. Consequently, the cutter-suction exploitation mode of marine gas hydrate is feasible in theory.
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