Exploration starts on large block in Central African Republic south of Chad oil project

Dec. 18, 2000
A Denver independent will prospect a large area of northern Central African Republic (CAR), just south of where an ExxonMobil Corp. group is moving to tap significant oil finds in southern Chad.

A Denver independent will prospect a large area of northern Central African Republic (CAR), just south of where an ExxonMobil Corp. group is moving to tap significant oil finds in southern Chad.

The rights granted to RSM Production Corp., an affiliate of Grynberg Petroleum Co. of Denver, cover 13.7 million acres in the Doba, Doseo, and Salamat basins which straddle Chad and the CAR. Grynberg is an independent international oil and gas company.

The Chadian part of the basins contains five oil fields with proved oil reserves of 1 billion bbl of oil and a potential of 5 billion bbl, RSM said. There is one other oil producing basin in Chad farther to the north known as the Chad (Termit) basin.

The World Bank has agreed to finance part of the cost of a 633-mile, 30-in. heated pipeline to be built by the ExxonMobil group from Kome, Miandoum, and Bolobo fields in Chad to Kribi, a port in Cameroon, to transport the paraffinic oil for export by tanker.

The ExxonMobil group has started infrastructure construction on the $3.5 billion project and is to begin laying pipe next year (OGJ Online, Oct. 19, 2000).

Projected production is 225,000 b/d. Establishing this production would involve the drilling in Chad by the ExxonMobil group of some 300 producing wells, starting in late 2001, to reservoirs at 5,200 ft. Production startup is set as early as 2003.

The Chad affiliates of ExxonMobil, Chevron, Malaysia's state Petronas, and China National Petroleum Corp. hold the concessions. Exxon, Shell, and Elf Aquitaine made the original discoveries.

CAR's president signed a decree on Nov. 24, capping more than two years of negotiations with RSM.

Geologic picture

The Doba, Doseo, and Salamat basins were formed in the Cretaceous period as a part of an extensive rift system in north-central Africa, especially in Nigeria, Chad, CAR, and Sudan, RSM noted. The prolific oil producing provinces known as the Benue trough in Nigeria, the Muglad basin in Sudan, and the Chad-Doba basins in Chad are all parts of this geologic rift system.

In all these basins, the Cretaceous-age sediments not only contain important hydrocarbon source rocks but also contain thick, porous, and permeable sandstone reservoir rock sequences. In addition, the younger sediments of Tertiary age in these basins also contain suitable sandstone reservoir rocks that, under favorable circumstances, may host significant hydrocarbon pools. The license area had approximately 3,600 km of 2D seismic profiles shot in the 1970s by Conoco.

Exxon drilled one well, Aoukale 1, to 8,125 ft on a farmout from Conoco in 1986. Aoukale 1 was projected to 9,840 ft and in RSM's opinion was not drilled deep enough to test the strata equivalent to the producing horizons in Chad.

RSM's program

RSM was to commence reprocessing and reinterpretation of all 2D seismic data immediately in conjunction with reinterpretation of existing gravity and 91,000 sq km of aeromagnetic survey data over the area. Following this will be acquisition and interpretation of more 2D and 3D seismic data before deepening the Aoukale 1 well and drilling more exploratory wells.

The contract has an initial 5 year period with extensions of 3 years and 2 years. It requires, among other things, acquisition of 400 line km of new 2D seismic and a geochemical survey in year 4 and drilling of one exploratory well in each renewal period.

"RSM's potential oil production, in all probability, will be connected to the Chad-Cameroon pipeline for export purposes after satisfying the domestic demand in CAR to the tune of approximately 3,000 b/d," RSM said. The Chad-Cameroon pipeline generally parallels the border with CAR on the way to Kribi.

The development of indigenous oil and gas potential in northern CAR is an economic necessity for the republic, especially now with the price of oil close to $30/bbl, RSM said.

ExxoMobil said the Chad-Cameroon project should bring benefits of $2.5-8.5 billion to Chad, depending on oil prices, and as much as $900 million to Cameroon during 25-30 years.