The favorable results of a recently concluded delineation study have added 12 million bbl of oil and 77 bcf of gas reserves to Seme field off Benin in West Africa.
This small but politically stable country is weighing various options to reduce its dependency on imported oil and power, says Gustavson Associates Inc., Boulder, Colo.
In addition to the proved gas reserves, a major structure has been identified in the Late Jurassic-Early Cretaceous Ise formation underlying the presently producing Late Cretaceous horizons. If gas charged, this new prospect would add another 330 bcf of gas to the country's energy budget.
The additional oil reserves were mapped in the producing H-6 through H-8 reservoirs. The additional gas reserves are in the Ise formation.
SEME FIELD HISTORY
Saga Petroleum AS of Norway originally developed Seme field. It produced oil from the H-6 reservoir until the late 1980s (OGJ, Feb. 11, 1985, p. 126).
At that time the Ministry of Energy, Mines and Hydraulics took over the operation with support from Ashland OH Inc. under the name Projet Petrolier de Seme (PPS). Declining production and very high operating costs brought the field economics deeply into negative cash flow.
A restructuring effort supported by the World Bank succeeded in refinancing PPS, and a technical audit performed by Gustavson Associates drastically reduced operating costs.
Although Seme field is only 12 miles offshore in calm waters of the Gulf of Guinea, the production operations were saddled with excess staff, labor, and equipment.
With the strong support and personal interest of newly elected President Nicephore Soglo, himself a market economist with experience from World Bank, PPS was restructured and in August 1993 turned profitable from an operating income standpoint.
It is still a marginal operation, and there is not enough capital to perform preventive maintenance of the five to six producing wells much less redevelop the newly identified structure.
Recent devaluation of the West African franc has further reduced local operating costs by about one third while oil liftings are paid in hard currency, but international partners are needed for future development, says John Gustavson, advisor to the ministry.
"We are grateful to learn of these positive results, in our own backyard," said Dr. Aurelien Houessou, minister of energy, mines, an d hydraulics. "The additional oil reserves should attract foreign partners for production and exploration. In addition, with the delineation of the gas reserves we now have a viable alternative to importing natural gas from Nigeria for our gas-fired power plant project."
GAS DEVELOPMENT
Gustavson Associates, working under a U.S. Trade & Development Agency grant, has established the economic feasibility of replacing part of the imported electric power with energy from a local, gas fired turbine.
The Seme reserves addition guarantees the security of the gas supply. A General Electric 40 mw gas turbine frame has been selected as optimum for the tropical conditions in Benin and could be expanded for future needs.
Other discoveries of both oil and gas along the Gulf of Guinea have generated serious attention in the World Bank plans for a major natural gas trunk line from Nigeria to run west through Benin, Togo, and Ghana and with possible linkage to new gas fields off Cote d'Ivoire. Benin, Togo, and Ghana have submitted comments to a proposed protocol among the West African countries, and comments are awaited soon from Nigeria.
A potential operator of the trunkline is Chevron Corp., which together with Nigerian National Petroleum Corp . has offered to perform a pre-feasibility gas demand study. Chevron and NNPC will I be major producers of gas into the existing but underused Escravos-Lagos pipeline.
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