Prospectivity of the Nigeria-São Tomé & Príncipe Joint Development Zone – an integrated geoscience approach

Abstract

The area of the Joint Development Zone (JDZ), between Nigeria and São Tomé & Príncipe, lies on the southern front of the Niger Delta. The delta is a prolific hydrocarbon-producing region with numer¬ous commercial discoveries of oil, condensate and gas. The JDZ is divided into 11 hydrocarbon exploration blocks that have undergone competitive bid licence rounds; notably in 2004 when nine blocks were offered and a year later when five blocks were offered. To date, eight wells have been drilled within the waters of the JDZ by major international oil companies and all are believed to have encountered hydrocarbons. Obo-1, Obo-2 and Enitimi-1 wells encountered oil and gas whilst Lemba- 1X, Malanza-1X, Oki East-1X, Bomu-1 and Kina-1XR found gas. These eight wells have only targeted structural traps – six of these wells have been drilled on hanging walls of the toe-thrusts, while only two (Obo-1 and -2) have targeted reservoirs within a footwall, encountering oil. In 2002, PGS acquired a 3000 km2 multi-client 3D seismic dataset over the northern part of the JDZ waters; this dataset was then reprocessed in 2007 through a Pre-Stack Time Migration sequence. The seismic survey covers Blocks 1 to 4 (and partially Blocks 5 and 6) covering the eight exploration wells and is situated in water depths of between 1500 and 2300 m.