Definition of Reservoir Configuration in Ancient Glacial Environment: Case History from Rima Field, South Oman

A. J. Penneycard

The Al Khlata Formation (Permian-Carboniferous) is an important reservoir unit of the "Eastern Flank" province of South Oman. The formation consists of an unusual series of glacial sand, silt, shale, and diamictite exhibiting such gross heterogeneity that conventional correlation techniques are ineffective. A threefold palynologic subdivision has been developed, which has allowed the recognition of a number of genetically distinct units. Major periods of erosion separate the units, erosive processes dominating the 20-40 million year period during which the Al Khlata accumulated. Deposition occurred in a sequence of deep valleys cut into the early Al Khlata and underlying Haima (Cambrian-Ordovician) reservoirs. The extent of these deposits is controlled by the morphology o these incisive valleys.

A case history of the large Rima field illustrates the use of palynology in unraveling the temporal and spatial relationships of the individual Al Khlata and Haima units. The resultant reservoir-geologic model of this internally complex field has enabled more confident assessment of variations in well performance with reservoir type, and has guided plans for future offtake levels and overall development planning.

AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.