Sand Remobilization Enhanced Complexity to Mounded Geometry, Early Tertiary Deep Water Sand Reservoirs, Balder Oil Field North Sea
Dag Bergslien, Morten Rye-Larsen, and Arnt I. Jenssen
Sand remobilization played a major role in generating the high relief mounded geometries that trap oil in the early Tertiary reservoirs at Balder Field in Norwegiai North Sea blocks 25/10 and 25/11. The thick massive submarine-fan sandstones were shed from the East Shetland Platform and deposited from high density turbidity currents. These thick massive sandstones lie in the distal portions of the fan system on the northwestern margin of the Utsira High. An intricate interaction between deposition and soft sediment deformation processes generated the complex cluster of thick mounded sand geometries comprising the Balder oil field. Slumping, sliding and sand remobilization with associated sand injections into overlying shales were the dominant deformation processes that manly occurred during the early Eocene. The field is comprised of three reservoirs, the Paleocene Heimdal and Hermod Formation and the Early Eocene Balder Formation. The sandstones, which have excellent reservoir properties, share a common pressure system and oil-water contact. This is probably related to the soft-sediment deformation and associated sand injections establishing cross-stratal communication.
AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California