南海东沙海域天然气水合物与地质构造的关系

构造作用和构造过程是控制天然气水合物发育和赋存的重要地质因素之一。陆坡区复杂的构造运动能够形成良好的气体运移通道以及欠压实、高孔隙的水合物储集空间。东沙群岛邻近海域具有水深变化大、沉积厚度大、沉积速率高和有机质丰富等天然气水合物有利赋存条件,最新的研究已经在该海域发现了天然气水合物赋存的地球物理证据BSR,针对东沙群岛海域广泛发育的断裂、底辟、海底滑坡等构造,开展了其与天然气水合物成藏的关系研究,可以进一步深入了解天然气水合物在东沙群岛不同地质构造中的分布特征与演化,为该区天然气远景评估提供参考。

RELATION BETWEEN GAS HYDRATE AND GEOLOGIC STRUCTURES IN DONGSHA ISLANDS SEA AREA OF SOUTH CHINE SEA

Tectonic process and structural functions are important geological factors which control the formation and existence of gas hydrates.Favorable channels for gas flowing and incompact reservoir with high porosity for gas hydrates can result from complicated structural movements in continental slopes.Dongsha Islands and adjacent area have favorable conditions for gas hydrate formation as they have large water depth,large sediment thickness,high sedimentation rate,and high organic matter.The recent study also lets us find geophysical identification sign BSR of gas hydrate.Using the present study results,we have done the relationship study between the gas hydrate occurrence and the fault fracture,mud volcano,and submarine landslide.This study will help find out the distribution characteristics and the evolution of gas hydrate in various structural fields,and make a contribution to the resource assessment of gas hydrate.