琼东南盆地中央峡谷天然气水合物成藏模式

Gas hydrate accumulation model in the Central Canyon of the Southeast Basin of Hainan

琼东南盆地是天然气水合物勘查开发先导示范区。选取琼东南盆地中央峡谷为研究对象,基于地球化学分析、地震资料解释和天然气水合物成藏条件等资料,分析天然气水合物成藏模式。结果表明:琼东南盆地天然气水合物的气源具有“热成因气为主、混合成因气为辅”的特征,主力气源岩具备充足的供烃能力。研究区发育的“通源连储”断裂、气烟囱—泥底辟—麻坑、海底滑塌体构成主要运移输导体系和储集体,在水合物形成聚集过程中具有重要控制作用,其中气烟囱为高效运移输导体,是有利勘查目标。琼东南盆地中央峡谷气田天然气水合物成藏模式为热成因气型渗漏型、渗漏—砂体复合型和生物成因气型扩散型3种。该结果为琼东南盆地天然气水合物资源评价和勘查提供参考。

Southeast Basin of Hainan is a gas hydrate exploration and development pilot demonstration area.Based on geochemical analysis,seismic data interpretation and accumulation conditions,the gas hydrate accumulation model is studied in the Central Canyon of the basin.The results show that the gas source of natural gas hydrate in the basin has the characteristics of thermogenic and mixed genesis,and the main gas source rock has sufficient hydrocarbon supply capacity.The faults,gas chimneys,mud diapirs,pockmarks and submarine slumps in the study area constitute the main migration and transportation systems and reservoirs,which play an important role in the formation and development of hydrate.Gas chimneys are effective migration and transportation conductors,and are favorable exploration targets at present.There are three types of gas hydrate accumulation models in the Central Canyon gas field of the basin:leakage type,leakage and sand body compound type of thermogenic gas,diffusion type of biogas.The results provide a reference for gas hydrate resource evaluation and exploration in the basin.