Kwanza Beach modern analog for oil and gas reservoir sandstone

Kwanza beach Angola

Atlantic Ocean Beach 3 km to the North of the Kwanza River mouth ( Angola, 70 km South of Luanda). Modern analog of the sandstone oil and gas reservoirs of the Jurassic of southwestern Siberia and Devonian of the Tatarstan. Observed features – steep beachface (1), storm ridge (2), flattened berm (3), and fragment of the first marine Holocene terrace (4). Darker spots at the berm of the storm ridge (shown with red arrow) is a natural concentration (mini placer) of heavy minerals (thickness not exceeding 1 cm). The width of the beach from the low tide mark to the brink of the first terrace is approximately 100 m. Thickness of beach sands is no less than 3.5 m. Width of the swash zone (with the photographed condition of 0.7 m waves) is approximately 17.5 m. Elevation of the storm ridge crest above the lowest tide mark is approximately 2.5 m. Beach sediments are coarse-to medium-grained predominantly quartz sands with minor shell hash. Lacks spots of coarse sand and gravel. Section of the beach taken at point 5, five meters inland from the storm ridge show layered sands with each layer being 0.15 m thick. Layers are graded beds with sands of various grain sizes enriched in heavy minerals. Crab burrows were found on the beach with the average frequency of 4 burrows per square meter. Photo by Oleg Khotylev, Moscow State University.