南海北部陆坡神狐海域水合物储层分层建模方法与有利区带预测

Hierarchical modeling method and favorable zone prediction of hydrate reservoirs in Shenhu waters in continental slope of northern South China Sea

南海北部陆坡神狐海域是我国水合物首次试采区,其峡谷区沉积作用复杂,影响因素较多,水合物区储层建模难度大。针对神狐海域水合物富集层段粤海组和万山组沉积过程的差异,划分出5个层序界面,提出不同层序采用不同方法进行表征的建模策略:针对峡谷边界清晰的层序Ⅰ、Ⅱ,采用基于对象模拟;针对明显侧向迁移峡谷边界的层序Ⅲ、Ⅳ,采用截断高斯模拟;针对峡谷边界不明显、底流侵蚀严重的层序Ⅴ、Ⅵ,采用序贯高斯模拟。利用该建模策略,基于构造模型,采用确定性建模与随机建模相结合建立了沉积物性模型,并将地震信息与沉积认识相融合建立了三维属性模型,在此基础上刻画了神狐水合物试采区有利储层分布范围。

The Shenhu waters in continental slope of northern South China Sea is the first pilot mining area of hydrates in China,the sedimentation in the canyon area is complex,several influencing factorsare co-exist in this area,and it is difficult to conduct the hydrate reservoir modeling.According to the difference on the sedimentary processes of the hydrate-rich Yuehai Formation and Wanshan Formation in the Shenhu waters,five sequence interfaces were delineated,and the modeling strategies of using different methods for different sequence were proposed,namely,the object-based simulation shall be used for the sequence I and II with clear canyon boundary;the truncated Gaussian simulation shall be used for the sequence III and IV with apparent lateral migration of canyon boundary;the sequential Gaussian simulation shall be used for the sequence V and VI with unclear canyon boundary and serious underflow erosion.According to this modeling strategy,a sedimentary property model combining deterministic modeling with stochastic modeling was established on the basis of structural model,and a three-dimensional attribute model was established by integrating seismic data with sedimentary understanding.On this basis,the favorable distribution scope of hydrate reservoir was delineated for the Shenhu hydrates pilot mining area.