南海天然气水合物的形成条件和分布特征

The forming condition and distribution characteristics of the gas hydrate in the South China Sea

从物理海洋、古气候、沉积环境和构造环境分析入手,研究了南海天然气水合物的形成条件。研究结果认为,在整个南海海域,天然气水合物生成的条件是存在差别的。南海东北部,在氧同位素2、4、6期,由于菲律宾海的高盐度海水的注入,使这里的生物生产率特别高,陆坡上沉积了丰富的有机物质,加上此期间该处的沉积速率高,为天然水合物的生成具备了物质条件;另外,自中新世末以来,由于菲律宾海板块与欧亚板块在台湾地区发生碰撞,对南海北部产生北西向挤压,加快了流体在沉积物中的活动,为天然气水合物的生成具备了良好的构造环境。因此,研究认为南海东北部陆坡应是南海天然气水合物最丰富的地区。

We have researched the forming condition of gas hydrate in the South China Sea according to the physical oceanography, palaeo-climate, sedimentary environment,, and tectonic environment. The researching results show that there are different forming condition of gas hydrate in South China Sea. In the northeast part of the South China Sea the high salinity water has flowed from Philippine Sea, therefore, the organism producibility was higher and there have rich organic materials in sediments of the periods of oxygen-isotope 2,4,6. In these periods the sedimentary velocity was very high, so there are good material condition for formation of gas hydrate. In addition, from the end of Miocene to present, the Philippine Sea plate has collided with Asian plate in Taiwan Region and extruded the northeast part of the South China Sea. As the extruding force in the sediments the fluid is very active and this is very good for the formation of gas hydrate. Therefore, we believe that there should be rich gas hydrate in the northeast slope of the South China Sea.