The Burgan Field of Kuwait
The Burgan Field is second most important oil field in the Middle East behind the Ghawar Field in Saudi Arabia. It accounts for most of the current and historical oil production of Kuwait. Recent press reports that production at Burgan will have to be scaled back from 1.9 to 1.7 million barrels per day have called attention to this major oil field.
The Burgan Field was discovered in 1938, but production did not begin until 1946. Burgan was developed rapidly and production first exceeded 1 million barrels per day in 1955 and 2 million barrels per day in 1968. Production reached a peak of 2.41 million barrels per day in 1972. From 1949 until 1972, when the Ghawar Field surpassed its production, Burgan was the most important oil field in the Middle East.
The main producing reservoirs at Burgan are sandstones of Cretaceous age. The gross productive section is about 1,220 feet at the crest of the structure. Four major sandstone horizons within this section account for most of the current and cumulative production. The fourth sand is much thicker than the others, so the original oil-water contact did not impinge on the base of the sand, even at the structural crest. A single oil-water contact cuts across all four sands in all three structural culminations. The productive area is more than 96,000 acres. The Mauddud limestone is present between the second and third sands, and is a minor oil reservoir. The four sands have a strong natural water drive, so water injection is not needed to maintain reservoir pressure.
The Burgan structure is an anticlinal dome with numerous radial faults. There are as many as 30 of these faults, typically three to four kilometers in length. Migration of magnesium-rich fluids along these fault planes has resulted in dolomite cementation, compartmentalizing the reservoir.
The compartmentalization of the main reservoir sands by these radial faults, combined with high production rates, resulted in water incursion problems even before the 1973 nationalization of the field. These problems were made worse by uncontrolled flow from wells sabotaged by the Iraqi military in 1991. Careful reservoir management since that time has limited the problem, but the second and third sands were largely depleted by 1992. The cumulative production of the Burgan Field is about 28 billion barrels of oil.
At current rates of production, the four main sands will be swept by water by the end of the decade. This will not be the end of oil production at Burgan; deeper reservoirs in the Lower Cretaceous Ratawi Limestone and Jurassic Marrat Formation contain significant oil reserves. Between the second and third sands there are also a number of thin, discontinuous sands known as the stringers. These formations represent a resource for the future, but production rates will be much less.
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Brennan, P., Greater Burgan Field, Treatise of Petroleum Geology, Structural Traps I, American Association of Petroleum Geologists, 1990
Carman, George J., Structural Elements of Onshore Kuwait, Geoarabia, Volume 1 #2, 1996
United States Energy Information Administration, The Petroleum Resources of the Middle East, 1982
Warsi, Waris E. K., Gravity Field of Kuwait and its Relevance to Major Geological Structures, Bulletin of the American Association of Petroleum Geologists, volume 74, #10, 1990