As early as 1896, wells were drilled in and around Half-Assini as a result of oil seeps found onshore Tano basin. Today one can still see some of these seeps at Bokakere. Between 1978 and 1985 oil was produced from the Saltpond field.

A number of oil, oil/gas and gas fields have been found in the Tano basin. In all eighty-nine (89) wells have been drilled in the country. Six (6) discoveries have been made. It is also worth mentioning that 75% of 50 exploratory wells drilled encountered varying degrees of hydrocarbon shows.

Since the inception of GNPC in 1983 to date, over 30,000 km of 2-D and over 5,000 km² of 3-D seismic data have been acquired. These data are available for review or licensing at the GNPC office.