A high-resolution 3D reflection seismic dataset acquired over a deepwater exploration block in the Orange Basin, offshore of South Africa was used to achieve a detailed description of the contractional domain within a gravity-driven system. Conventional seismic analysis combined with novel horizon-based and volumetric seismic attributes highlight 5 main stratigraphic intervals, ranging from Cenomanian-Turonian to present-day in age. Coniacian to Santonian stratigraphic sequences were disrupted by numerous folds and a thrust fault system. The thrust fault system soles into two detachment layers, which coincide with the shale hydrocarbon source rocks at the Cenomanian−Turonian boundary and the top of the Turonian marine shale unit. The thrust fault system also propagates upwards into the Maastrichtian and Palaeogene sedimentary units and exploits S to WSW dipping normal faults along which hydrocarbons appear to have been transported to the present-day seafloor, forming pockmarks. Seismic attributes show 6 large pockmarks with diameters between 700 m and 1100 m and depths between 75 and 103 m. Thus, we suggest that hydrocarbons from the Cenomanian−Turonian source rocks were channelled up-section by the Cenomanian-Santonian thrust faults, followed by smaller-scale S-WSW dipping normal faults and in turn escaping into the ocean, resulting in pockmark formation.

在南非海上奥兰治盆地的深水勘探区块上采集的高分辨率3D反射地震数据集用于实现重力驱动系统内收缩域的详细描述。常规地震分析与新颖的基于水平和体积的地震属性相结合，突出显示了5个主要的地层间隔，范围从Cenomanian-Turonian到当今时代。多次折叠和逆冲断层系统破坏了科尼亚西至桑顿地层序列。逆冲断层系统分成两个分离层，这两个层与在Cenomanian-Turonian边界和Turonian海洋页岩单元顶部的页岩烃源岩重合。逆冲断层系统也向上传播到马斯特里赫特和古近纪沉积单元，并利用S到WSW浸入正常断层，沿着这些断层，碳氢化合物似乎已被输送到当今的海底，形成了麻点。地震属性显示了6个大麻点，直径在700 m至1100 m之间，深度在75至103 m之间。因此，我们认为，来自Cenomanian-Turonian烃源岩的碳氢化合物是由Cenomanian-Santonian逆冲断层引导的，然后是较小规模的S-WSW浸入正常断层，然后逃逸到海洋中，从而形成麻点。地震属性显示6个大麻点，直径在700 m至1100 m之间，深度在75至103 m之间。因此，我们认为，来自Cenomanian-Turonian烃源岩的碳氢化合物是由Cenomanian-Santonian逆冲断层引导的，然后是较小规模的S-WSW浸入正常断层，然后逃逸到海洋中，从而形成麻点。地震属性显示了6个大麻点，直径在700 m至1100 m之间，深度在75至103 m之间。因此，我们认为，来自Cenomanian-Turonian烃源岩的碳氢化合物是由Cenomanian-Santonian逆冲断层引导的，然后是较小规模的S-WSW浸入正常断层，然后逃逸到海洋中，从而形成麻点。