​ The exploration activities cover a huge concession area (Exploration Blocks 1A, 2A and 4 and development block IB & 2B) about 50,000 sq. km. The EPSA (Exploration and Production Sharing Agreement) between the Government & the Consortium was signed on 1st March 1997 with effective date starting from 20th November 1996. ​ Exploration & Production​The duration of the contract is 30 years from the effective date. Some 620 MMBBL recoverable reserves have been discovered to date and the exploration target is to increase the total reserves up to 950 MMBBL by year 2003, in order to sustain long term oil production. Currently 6 fields have been developed to achieve production of more than 300,000 barrels of oil per day.​
As of April 2000 a total of 73 exploration wells (41 wildcats with 27 discoveries - 66% success rate) were drilled. The main hydrocarbon-bearing reservoirs drilled within 1300 up to 4500 m are from the prolific non-marine Aradeiba and Bentiu sands deposited in the Muglad basin. A total of 10840 Km 2D seismic and 1445 km 2 of 3D seismic data had been acquired up to April 2000. The initial operations utilized four drilling rigs, two service rigs and one water well rig. Due to improvement in drilling efficiency, one drilling rig was released in March 1999 and only two drilling rigs were retained from September 1999 onwards.


Production of oil started in June 1999. By the end of October 2004 the commutative production from all fields was 461,000,000 BBLs. 8 fields are contributing in production namely Heglig, Unity, Toma South, El Nar , El Toor,Bamboo,Munga & Diffra. The average flow rate for February and March 325,000 BBL/DAY. Power plant at Heglig & Unity of 75 MW were constructed and commissioned to provide electrical power via 300 kms of electrical transmission to all seven fields.