The world's largest intrusive and extrusive sand bodies are found in the North Sea and may represent economically interesting reservoirs!
Using 3-dimensional seismic and well data from the northern North Sea, Statoil describse the world’s largest extrusive sand body (10 km3) and even larger intrusive sand bodies.
– Large intrusive and extrusive sands represent economically interesting reservoirs, says Helge Løseth in Statoil who will present a talk at the forthcoming Hydrocarbon Habitat seminar in February based on extensive studies of these phenomenons.
The upper intrusive sand bodies in the northern North Sea are embedded in Upper Oligocene ooze-rich claystones and both top and base of the sandstones are expressed as relatively high-amplitude peak and trough reflections.
Løseth says that Statoil produce water from a 150 m thick and 3 km3 large intrusive sand body above the Visund Field to for the purpose of injecting “scale free” water into the Jurassic reservoir.
Extrusive sand bodies are interpreted around the flanks of all mounds but the largest is found above the Snorre Field.
The sand body covers an area of more than 260 km2, is up to 125 m thick, fills low areas around mounds, which formed when underlying sand injectites lifted the overburden, wedges out away from a central thick zone, is locally absent along irregular ditches, 20 km long and up to 50 m deep, which overlie feeders on the flanks of the mounds, and consists of fine-grained to medium-grained, sub-rounded to rounded grains.