The area was first explored in the 1970’s by Phillips and Arco, drilling shallow wells on 2D seismic on the Tano North and Tano South structures.  Later operators included Dana, GNPC and Tullow in the period 2000 to 2009, drilling on 3D data.  In spite of a number of appraisal wells on the original discoveries and some outpost structures, no firm plan of development for the area emerged, with the discovery of Jubilee/Mahogany in 2008, exploration efforts shifted into the deeper water, Turonian ponded tubidite reservoirs in deeper water. 19 wells have been drilled to date on the East West of the Asset.

Ghana: Expanded Tano Shallow Block
Awarded in March 2014
Combined surface area of 1,508 km2 in water depths of zero to about 200 meters.

The Tano Shallow comprises three legacy discovered fields (South Tano 1978; North Tano 1980 and West Tano 2000), which are located 15 to 35 km offshore in water depth between 55 and 116 meters.  Given the present advancements in production technology and sub-surface interpretation the fields are currently under evaluation for economic viability for development.
The equatorial margin of Ghana has recently been proven a prolific basin with successful tests of the basin floor fan plays and up-dip connectivity via channel complexes and incised valleys throughout the Upper Cretaceous sequences. Our exploration efforts on Tano Shallow integrate these new concepts and the enhanced knowledge base with the goal to increase the hydrocarbon potential of the Tano Shallow block.

Field Summaries – GNPC 2009

Tano North

  • Discovered by Phillips in 1980
  • Drilled four wells
  • Water depth of 55mm
  • 15 km to shore
  • Max Flow rates of 8.4 MMscfid & 1400 bopd (after fracturing)

Tano South

  • Discovered by Phillips in 1979
  • Drilled eight wells
  • Water depth of 100m
  • 35 km to shore
  • Max Flow rates of 8.2 MMscfid & 1614 bopd (32 deg API)

West Tano

  • Discovered by Dana in 2000
  • Drilled two wells
  • Water depth of 116m
  • 30 km to shore
  • Max Flow rates of 754 bopd (15 – 19 deg API)

Ghana Oil and Gas Profile

  • Ghana discovered her first large-scale, commercially viable oil field in 2007. The first commercial production is slated to commence during the last quarter of the year – 2010. Since the discovery, major players such as Petrochina and Exxon have been trying to acquire an interest in the country.
  • The US geological survey estimates that the “Gulf of Guinea Province” which lies partly in Ghana’s waters, contains 4,071 MMBO, 34,451 BCFG, and 1,145 MMBNGL


Five (5) sedimentary basins have been identified in the country. These are:

  • The inland Voltaian basin
  • Offshore Accra-Keta basin with an onshore extension
  • Offshore Saltpond (Central) Basin
  • Offshore Tano basin with an onshore extension
  • Offshore Cape Three points (this is sometimes considered as part of the Tano basin)



  • In June 2007, the Kosmos Energy team discovered the Jubilee Oil Field following the drilling of the Mahogany-1 exploration well in Ghana’s deep waters. This is possibly one of the largest oil finds in the last decade offshore West Africa. With this discovery, Ghana went from being a country without oil, to potentially becoming a major player.
  • The estimated resource range for the Jubilee Oil Field, is now estimated to be between 600 million barrels of oil equivalent (BOE) and 1.5 billion BOE.
  • Chinese companies have been actively seeking opportunities and signed an agreement with the Ghanaian Government in September 2010