随着现代科学技术进步和海洋开发飞速发展，海洋非常规油气资源开发提上日程。然而，海洋非常规油气尚未形成统一且明确的概念，仍处于初期构建阶段。目前，由于技术手段所限，海洋非常规油气概念仅限于现代海洋环境中海相沉积地层中的非常规油气资源，主要考虑以下几种类型：天然气水合物、浅层气和页岩气／页岩油。以琼东南盆地为例，深水盆地具有天然气水合物、浅层气藏和深层气藏空间共存的特点：200 m海底沉积物中形成了天然气水合物，浅层气赋存在天然气水合物层下，深层气藏主要聚集在中部峡谷和中生代潜山。由于三者压力和储层特征差异较大，联合开发利用需要采用多采气管分层采气，防止层间干扰技术、多边钻井技术和防砂技术是天然气水合物、浅层气藏和深层气藏联合开发的关键问题。天然气水合物、浅层气藏和深层气藏并存，使琼东南盆地成为三气联合开发的理想靶区，因此，琼东南海域是实现多气合采的有利海区。

With advances in modern science and rapid offshore development, the development of marine unconventional hydrocarbons is placed on the agenda. However, a clear definition has not been established and is in an early formative stage. At present, because of technological limitations, the concept is confined to unconventional resources in marine sedimentary strata of modern marine settings, mainly methane gas hydrate, shallow gas, and shale gas/oil. Using the Qiongdongnan Basin in the northern South China Sea as an example, the distribution and coexistence of these resources were evaluated. In the deep-water basin, methane gas hydrate is formed within the upper ~ 200 m of seafloor sediments. Shallow gas is hosted beneath the hydrate-bearing interval. Deep gas reservoirs are mainly present in the central canyon and Mesozoic buried hills. Because their pressure regimes and reservoir properties differ, co-production is required to use multi-tubing zonal production, technologies to prevent interlayer interference, multilateral drilling, and sand-control measures. The coexistence of gas hydrate, shallow gas, and deep gas makes the Qiongdongnan Basin an ideal target for integrated three-gas development. Therefore, the Qiongdongnan offshore area is considered a favorable region for multi-gas co-production.