海底天然气渗漏系统水合物成藏动力学及其资源评价方法

KINETICS OF GAS HYDRATE RESERVOIR FORMATION AND GAS POTENTIAL ASSESSMENT IN THE MARINE GAS VENT SYSTEM

根据海底天然气渗漏系统沉淀水合物的动力学模型,计算了海底渗漏系统中渗漏天然气沉淀为水合物的比例。如果BushHill渗漏系统海底水合物或喷溢天然气的化学组成是渗漏系统气源天然气通过沉淀水合物转变而成,则需要约3. 3% ~21. 7% (平均12. 9% )的渗漏天然气在海底沉淀为水合物。结合渗漏系统的活动时间(1万年)和天然气流量(800t/a),沉淀在墨西哥湾GC185区BushHill渗漏系统中的水合物天然气资源为0. 37×109 ~2. 43×109 m3,平均为1. 45×109 m3,与体积和含量评价方法获得的结果基本一致。

By using the kinetic model of hydrate precipitated in gas vent system, the fraction of venting gas precipitated hydrate was calculated. There was 3.3%~21.7% of venting gas with average 12.9% precipitated hydrate in the Bush Hill vent system if the source gas composition was converted to the observed vent or hydrate gas composition on the seafloor. Combined with the active time (10~4a) and gas mass flux (800 t/a) of the Bush Hill vent system, about (0.37~2.43)×10~9 m^3 of hydrate gas with a mean of 1.45×10~9 m^3 was accumulated in the subsurface in the Bush Hill gas vent system in GC 185 of the Gulf of Mexico. This value is consistent with the former estimated result by the method of volume and contents of hydrate.