气体水合物的基本特征、形成条件及成因初探

STUDY ON THE BASIC FEATURES, CONDITIONS OF FORMATION AND ORIGIN OF GAS HYDRATES

气体水合物为冰雪状笼形包合物，由甲烷（乙烷、二氧化碳等）和水在低温高压下形成。主要有两种结构（结构Ⅰ型和结构Ⅱ型），两种成因类型（生物成因和热解成因）。分布于极地永冻层和海底沉积层中。海底温度和压力、地热梯度、气体成分、同生水盐度等控制着水合物稳定带基底的深度和厚度。

Gas hydrates are ice-like inclusion compounds formed by methane (ethane carbon dioxide) at high pressure and low temperature. There are two primary structures ( structureⅠ and structureⅡ) and two major genetic types(thermogenic and biogenic) for gas hydrates. They are distributed in polar permafrost horizons and submarine sediments. Submarine temperature, pressure, gas compositions, geothermal gradient and syngenetic water salinity control the depth of hydrate zone basement. Autochthonous bacteriogenic model and pore fluid diffusion model are two genetic models.