海洋天然气水合物与深水油气共生关系研究对深水油气藏的勘探与开采、海底滑坡诱因评价以及全球气候变化和碳循环的重新认识具有重要的理论和实际意义。文章梳理了气源、封盖和遮盖侧储3种共生关系的主要研究进展，概述了南海北部深水区水合物与油气共生研究现状，结果表明，深部烃源岩或热解油气藏对浅部水合物成藏的气源供给多未充分评价；除极少部分地区外，下伏气藏的资源潜力不乐观；多数情况下，水合物层不是高质量的封盖层，难以形成有效圈闭，当其联合构造圈闭、地层圈闭、岩性圈闭或冻土层圈闭等时，可能形成相对有效的复合圈闭。今后的共生关系研究中可关注亚生物气和原油降解气对水合物气源的贡献，以水合物层中的断裂区为切入点来揭示水合物层的封盖机理。%The research on coexistence between marine gas hydrates and deepwater petroleum systems has great significance to exploration and exploitation of both deepwater hydrocarbon reservoirs and shallow gas hydrates, to the inducement of submarine slide and to the development of new insights on global climate change and earth’s carbon cycle. The new advances in leaking, capping and capping side-accumulation coexistence relationship are systematically summarized. According to the investigation, for the most part, the contributions of deep-seated oil and gas to shallow gas hydrate field have likely been underappreciated. The restricted discrimination among different sources of carbon trapped within gas hydrate confines the recognition of leaking coexistence between deepwater petroleum systems and shallow gas hydrates. Significant attention has been paid to the hydrocarbon supply from deflected hydrocarbon migration by low-permeability hydrate-bearing sediments and gas hydrates dissociation during geological history to conventional petroleum accumulations. Except for very few geological provinces, the resource potential of free gas trapped beneath gas hydrate is not significant. In most cases, gas hydrate-bearing sediments are not a high quality seal, unless structural, stratigraphic, lithologic, or/and permafrost traps have been involved, forming a relatively effective trap for upward hydrocarbon flow. We suggest as additional research on how to assess hydrate-bound gas sources from sub-biogenetic gas and secondary biogenic gas produced by anaerobic biodegradation of crude oil and thermogenic gas, and to illuminate the low trapping capacity of gas hydrate-bearing sediments by mathematic model.
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