琼东南盆地深水区天然气水合物成藏主控因素及模式

通过综合解释琼东南盆地深水区的最新钻井、测井和地震资料，结合盆地数值模拟分析，对研究区天然气水合物成藏的主控因素开展了研究，建立了琼东南盆地深水区天然气水合物的成藏模式。结果表明，气源岩、输导体系、稳定域、块体搬运沉积体系（MTDs）以及储集层的岩性差异是控制天然气水合物形成和富集的重要因素。琼东南盆地古近系烃源岩和浅层有机质可提供充足的气源，由底辟构造、气烟囱以及断层共同组合形成的网络输导体系控制了烃类气体的运移、聚集和天然气水合物的形成，粗粒沉积物和稳定域内的MTDs可为天然气水合物的富集和成藏创造有利储层条件和盖层条件。综合分析认为，气源通道和MTDs是控制高含气饱和度天然气水合物矿藏形成的最为关键的因素；深部构造和MTDs较为发育且靠近生烃凹陷的区域是高含气饱和度天然气水合物聚集的有利地区。

Main controlling factors and patterns of gas hydrate accumulation in the deep water area of Qiongdongnan Basin

Through the comprehensive interpretation of the latest drilling, logging and seismic data in the deep water area of Qiongdongnan Basin, in combination with the numerical simulation of the basin, this paper carries out a research on the main controlling factors of hydrate accumulation in the study area, and establishes an accumulation pattern of gas hydrate in the deep water area of Qiongdongnan Basin. The results show that gas source rocks, pathway systems, hydrate stabilization zones, mass transport deposition systems (MTDs), and differences in reservoir lithologies are important factors that control the formation and enrichment of gas hydrates. The Paleogene source rocks and shallow organic matters in Qiongdongnan Basin can provide sufficient gas sources. The network pathway systems formed by the combination of diapir structures, gas chimneys and faults controls the migration and accumulation of hydrocarbons and the formation of gas hydrates. MTDs in coarse sediments and hydrate stabilization zones can create favorable reservoir conditions and caprock conditions for gas hydrate enrichment and accumulation. The comprehensive analysis suggests that gas migration pathways and MTDs are the most critical factors for controlling the formation of gas hydrate deposits with high gas saturation. Deep structures and the areas where MTDs are relatively developed and close to hydrocarbon-generating sags are favorable areas for gas hydrate accumulation with high gas saturation.