构造控制型天然气水合物矿藏及其特征

构造环境是天然气水合物富集成藏的重要控制因素,增生楔、断裂体系、褶皱、(泥)底辟、滑塌等特殊构造体是影响天然气水合物成藏的主要地质载体。通过对这些特殊构造体与天然气水合物成藏关系的研究,结合流体活动对水合物形成的影响,总结出陆缘地区有增生楔型、盆缘斜坡型、埋藏背斜型、断褶型、滑塌型及底辟型等六类构造控制型水合物矿藏。南海位于欧亚板块、太平洋板块及印澳板块的交汇处,早期为活动陆缘,晚期演化为被动陆缘,其构造活动具有早期张裂、后期挤压的特点,这既不同于被动陆缘,也有别于活动陆缘,可视为“复合型”大陆边缘,兼具了“被动陆缘沉积速率高、活动陆缘构造活跃”的优点,从而形成了“增生楔型、断褶型、底辟型、滑塌型、盆缘斜坡型”等多种构造控制型水合物矿藏,是“复合型”大陆边缘水合物成藏地质模式的典型代表。

Tectonic Controls on Gas Hydrate Deposits and Their Characteristics

Tectonic environment is an important factor of gas hydrate formation.Special structure bodies,such as accretionary prism,fault-folded system,mud dirpir and slide body are important geological reservoirs of gas hydrates.Based on studying of these special structure bodies and fluid movements for gas hydrate formation,six types of tectonic-controlled gas hydrate reservoirs including accretionary prism,buried anticline,basin-edge slope,fault-folded,slide and dirpir are summarized.The South China Sea is located at the junction of the Eurasian,the Pacific and the Indian-Australian plates,and it is one of the complex continental margins which are of active margin in early and passive margin in late.Five tectonic types of gas hydrate deposits including accretionary prism,fault-folded,dirpir,slide type and basin-edge slope are identified in the South China Sea.