The Ima Field was discovered in the 1970s by Japan Petroleum. At that time the field was not considered economic for development.

Amni acquired the license in 1993 and entered into a partnership with Liberty Technical Services to explore and develop the License. Appraisal drilling commenced in 1994 and following the successful appraisal and development activities, production facilities were installed and oil production commenced in 1996. Facilities installed included a Well Head Platform, a Production Unit, pipeline system and an offshore terminal with an FSO, the Ima Terminal. With the acquisition of the Langley, the production platform, Amni controlled the ownership of all the Field Production Facilities. The partnership with Liberty was dissolved in 1998 and Amni assumed sole operatorship.

Further development drilling was undertaken in 2002 with the sidetrack of two existing wells and in 2010 drilling of two new wells prolonged the field life and increased the reserves recovery.

The (NAG) Ima Gas reserves lie above the Ima Oil Field and were discovered at the same time as the Oil reserves.

In 2005 Total entered into a Joint Venture Agreement with Amni by acquiring a 40% working interest in both OMLs 112 and 117. 

An additional appraisal well Ima-12 was drilled in 2006 and confirmed reserves of over 1.6 TCF (P1) of lean gas. The proximity to the NLNG facilities and access to deep water allows a range of development options. Amni, together with TOTAL, continue to move towards the production of the Ima Gas Field.