南海北部天然气水合物富集特征及定量评价

为寻找有资源前景的高富集天然气水合物及水合物储层的精细刻画方法，利用南海6次钻探发现的高饱和度水合物层的测井、岩心和三维地震数据，分析水合物富集层测井与地震异常特征.发现:（1）不同饱和度的孔隙与裂隙充填型水合物层的测井和地震异常不同，裂隙充填型水合物层具有各向异性；（2）受高通量流体运移的影响，在粉砂沉积物的水合物稳定带底界附近能形成中等饱和度的水合物层，识别标志为稳定带内极性与海底一致的强振幅反射，而非BSR和振幅空白；（3）裂隙充填型中等饱和度水合物层在地震剖面上表现为地层上拱和弱-中等强度振幅反射.储层-疏导-气源的耦合控制着水合物的富集特征和分布，断层与流体运移控制着细粒粉砂质沉积物中水合物的富集与厚度.基于饱和度岩相的统计学反演，能识别3 m非水合物和低饱和度水合物层及空间分布. 

The Characteristics of Gas Hydrate Accumulation and Quantitative Estimation in the North Slope of South China Sea

To identify and quantitatively estimate the prospective gas hydrate accumulation, we use the well log, core samples and three dimensional seismic data acquired by six gas hydrate drilling expeditions in the North South China Sea to study the well log and seismic anomalies and characteristics of high concentrated gas hydrate accumulation. (1) Pore-filling and fracture-filling gas hydrate with different saturations have different well log responses and the seismic reflection characteristics. The fracture-filling gas hydrate has the anisotropic characteristics; (2) the concentrated gas hydrate-bearing layers in the silty sediments occur just above the base of gas hydrate stability zone controlled by high flux fluid migration. The high amplitude reflection and the same polarity with the seafloor reflection are the direct indicators for identification of high concentrated gas hydrate accumulation; (3) fracture-filling gas hydrate with moderate saturation in seismic profile is characterized by the pull-up and weak-moderate amplitude reflections. The multi-parameter coupling of reservoir, fluid migration and gas source contributes to the concentrated gas hydrate accumulation, and faults and fluid migration control on the thickness and saturation of gas hydrate-baring sediments in the fine-grained sediments. It is confirmed that geostatistical inversion with the lithofacies constraint of gas hydrate saturation can estimate 3-m-thick non-gas hydrate and low saturation gas hydrate reservoir properties and delineate the spatial distribution.