Recently, oil exploration activities have shifted to the deep water offshore of the Niger Delta. Offshore activities have intensified in recent years and have accounted for over 50% of oil production in Nigeria. The deepwater extraction plants are less disturbed by local militant attacks, seizures due to civil conflicts, and sabotage. One significant deepwater discovery is the Agbami field that holds more than 1 billion barrels of reserves and ranks among the single largest deepwater discoveries in the world.
Location of Agbami oilfield
Agbami Fieldis an oil field located 220 miles south-east of Lagos and 70 miles offshore Nigeria (fig. 11a, b). Discovered in late 1998, it was the second major deepwater oil field discovered off the Niger Delta, the first being Bonga Field by Shell. The field is located in nearly 1,500 meters (4,900 ft) of water off the central Niger Delta. The operator of the field is Star Deep Water Limited, an affiliate of Chevron. Also involved in the field are Famfa Oil, an indigenous oil company owned by the Alakija Family of Lagos, Petrobras (Brazil), Statoil, and NNPC (the national oil company of Nigeria).
The field housed the largest FPSO (Floating Production Storage Offloading vessel), the key vessel through which all production stage activities take place in deep-water in the world (fig 12a,b). The Agbami project is the largest deep-water project yet in Nigeria.
Geology of the area
Most of the reserves are in lower and middle Miocene deep-water turbiditic sandstones and reserves are estimated at 900 MMbarrels with upside to perhaps 1.5 Billion barrels making it either the biggest or second biggest (to Bonga) deepwater field in Nigeria. Its crude oil quality is very high API gravity in the high 30's (very flowable) and the crude is sweet (low sulfur). The trap is mainly anticlinal 4-way rollover but internally the doubly plunging anticline is cored by a small reverse fault and upwardly diapiric mobile shale or mud. The northwestern portion of the field is over-thrusted at shallow levels.
Production
Production began in 2008 at over 70,000 barrels per day (11,000 m3/d) with peak production estimated to be at approximately 250,000 bls/d. The Floating Production unit is the length of three football fields and cost over $US4 billion to build. The Agbami field is the largest deepwater discovery to date in Nigeria, with estimated recoverable reserves of 900 million barrels. "Production from Agbami will now bring new energy supplies to the world market and help provide long term, sustainable returns to our shareholders," Ali Moshiri, president of Chevron Africa and Latin America, said.As with many other West African discoveries, it is primarily an oil field with associated gas. Oil from the reservoir is light (47° API), sweet crude with low levels of contaminants. Associated gas is reinjected to the reservoir for pressure maintenance and to eliminate gas flaring. Table 3 shows the production schedule for Agbami oilfield.
