固态流化采掘海洋天然气水合物藏破碎参数的优化设计

选取合理的采掘破碎工艺参数和喷嘴结构参数,是实现海洋天然气水合物(以下简称水合物)藏固态流化商业化采掘的关键之一。为了分析实际工程中影响水合物射流破碎效率的因素,依托室内实验和中国南海北部荔湾3站位现场试采取得的数据,以产气量12×10~4 m~3/d作为水合物商业开采目标,采用k—ε湍流模型开展了不同喷嘴直径、泵压等参数情况的仿真模拟分析。研究结果表明:(1)确定了水合物射流破碎临界速度为24 m/s时的喷嘴直径、泵压、排量关系曲线;(2)满足商业开采的单日水合物沉积物采掘量的破碎速度为2.48 m~3/min,其所对应的射流破碎孔径为800mm;(3)在喷嘴直径确定的情况下,直接提升射流排量和泵压会对工艺流程中其他零部件造成一定的损害。结论认为,所优选出的海洋非成岩水合物藏固态流化商业化采掘破碎的设计参数,为固态流化开采水合物破碎参数的优化设计提供了帮助。

An optimal design of crushing parameters of Marine gas hydrate reservoirs insolid fluidization exploitation

To select reasonable excavating and crushing process parameters and nozzle structure parameters is one of the key factors to realize commercial excavation of marine natural gas hydrate (hereinafter "hydrate" for short) in solid fluidization exploitation. For analyzing the factors influencing jet crushing efficiency of hydrate in actual engineering, nozzle diameter, pump pressure and other parameters were simulated and analyzed in k–ε turbulence model based on the laboratory experiments and the field production test data at Liwan 3 Station in the northern South China Sea with a gas production rate of 12×104 m3/d as the target of commercial hydrate exploitation. And the following research results were obtained. First, the relationship curves of nozzle diameter, pump pressure and displacement are determined when the critical jet speed for crushing hydrate is 24 m/s. Second, the crushing rate to satisfy the daily hydrate sediment excavation of commercial exploitation is 2.48 m3/min and its corresponding jet crushing diameter is 800 mm. Third, when the nozzle diameter is fixed, other parts in the process will be damaged if jet displacement and pump pressure are increased directly. In conclusion, these selected design parameters for commercially excavating and crushing marine non-diagenetic hydrate by means of solid fluidization are conducive to the optimal design of crushing parameters of hydrate in solid fluidization exploitation.