Commercial oil at long last
Ghana's discovery of crude oil in 2007 was greeted with euphoria. All over the world, rich countries are often associated with substantial reserves of hydrocarbons. In the 1970s, the Organisation of Petroleum Exporting Countries (OPEC) was a dominant force.
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Countries sought the "black gold" and Ghana was no exception. The country has four oil and gas basins: the Tano Basin bordering Côte d'Ivoire, the Saltpond Basin, the Accra/Keta Basin, and the Inland Voltaian Basin.
The search for oil in Ghana dates back to 1896. From ground seepages, you could scoop oil off the ground in parts of the Western Region (in the Onshore Tano Basin), much of which was used to light lamps. It was a period of sporadic onshore shallow drilling by several explorers.
This initial period with no geological understanding or seismic data can be described as the first phase of the search.
In the first half of the 20th century, several companies drilled shallow wells for light crude with limited success.
Significant progress
A major development took place in 1956, with the arrival of the American oil company, Gulf Oil. They were the first to begin drilling deep wells in the Western Region.
The Russians came in soon after independence and took exploration beyond the Western Region, carrying out a survey of the entire Voltaian Basin. There is very little information on these wells, which were also drilled without seismic data. They were also largely unsuccessful.
A second phase of exploration began in 1970, when Signal Oil Company arrived from the United States (US) and discovered the Saltpond Oil Field. This was the first commercial success in Ghana and it was offshore Saltpond in the Central Region of Ghana. This field was developed by Canadians under the company Agripetco. They produced the first oil after eight years. At the time, Shell Oil Company was also drilling in the Voltaian Basin, all the way up to Brong Ahafo, using data the Russians had collected earlier.
In I978, Phillips Petroleum found the South Tano fields offshore Western Region. Several small gas fields were found, but they were never in commercial quantities. It was a time of numerous operators beginning to look into shallow offshore prospects.
A third phase exploration is often associated with the creation of a national oil company (the Ghana National Petroleum Company — GNPC) in the late 1980s and ends with the discovery of oil in 2007. The creation of GNPC provided the search effort with a new impetus. GNPC began an intensive data acquisition effort. This is the period of intensive study and drilling activities and building of institutional capacity. To accelerate the exploration efforts, in 1989, GNPC funded the acquisition, processing and interpretation of the first 3D seismic survey over the South Tano Field with the firm conviction that the field was viable.
In 2004, they struck a partnership with Kosmos Energy from the US. Kosmos arrived in Ghana and set about shooting seismic and analysing data from the country's established offshore province — the Tano Basin. The Phillips Petroleum concept of shallow offshore was now taken into deep waters.
Deepwater drilling was very risky and expensive. At the time, the more established players considered it too risky. A much smaller player, Anadarko, agreed to take part and provided the rig to drill Mahogany-1, the well that was to discover the Jubilee Field.
Drilling
The first well Kosmos drilled struck commercial oil. Right from its inception as an exploration company in 2003, Kosmos has demonstrated a deep, focused approach in its drilling activities.
The founders of the company had worked together as a team earlier at Triton Energy and had discovered oil in Equatorial Guinea. Their approach, however, meant that the study period was a far more expensive one and so the new company went to the market in search of capital and found high-risk equity funds prepared to support it in its approach. Where others saw risk, Kosmos saw opportunity because of their unique expertise, ability to capitalise on opportunities and ability to act quickly.
The uniqueness and boldness of the Kosmos strategy was there for all to see. Kosmos brought together the industry's best geoscientists who understood a particular kind of rock type — the Cretaceous. They were going to focus only on Cretaceous geology found mainly in West Africa and the northeast coast of South America.
The Ghana discovery proved Kosmos right when within three years of being in Ghana, the company struck commercial oil in June 2007.
It took more than 100 years to find Jubilee, bringing an end to an important phase in the ongoing search for the black gold.