南海北部陆坡气源条件对水合物成藏影响的模拟研究

A study of modeling the effects of gas sources on gas hydrate formation in the northern slope of South China Sea

南海北部陆坡包括神狐海域在内无论在横向上还是纵向上影响水合物形成与分布的地质因素差异较大,其气源条件的变化是否为一种重要因素值得探索.本文将前人南海北部陆坡气源类型和气体组成概括为14种情况,分别运用模拟手段定量-半定量地分析它们对水合物成藏可能带来的影响.模拟结果显示,与神狐海域已知水合物相比,不同气体组成形成水合物所需温度条件增大0.49～5.44℃,多数增大2℃以上.可以看出,不同气体组成明显改变水合物的形成条件,暗示着不同类型气源可能是影响南海北部陆坡水合物形成与分布的重要因素.

In the northern slope of South China Sea including the Shenhu area, geological factors affecting gas hydrate formation and distribution are differential horizontally and vertically, and whether the variation of gas sources is an important resultant factor is worth exploring. In this paper, based on existing data, 14 cases of gas sources are summarized and are afterwards utilized to semi-quantitatively analyze their effects on gas hydrate formation by modeling in the northern slope of South China Sea. Modeling results show that various gas sources will enhance temperature conditions for gas hydrate formation by 0. 49 ~C to 5.44 ~C, mostly by more than 2 , compared with known gas hydrate in the Shenhu area. This indicates that various gas sources greatly change gas hydrate formation conditions, suggesting that they are probably important factor to affect gas hydrate formation and distribution in the northern slope of South China Sea.