Storytelling of the AMENAM Oil and Gas Discovery (Offshore Niger Delta)

Abstract

The AMENAM 1 well discovery (1990) closed a two years successful campaign led by the Elf Nigeria Exploration Direction (J.B.) in the conventional Offshore Eastern Niger Delta. For the first time, hydrocarbon bearing reservoirs were reached below 3400m to 4700m sea floor confirming the deep prospectivity of the upper Miocene stratigraphic series in this area. The structure was initially identified and picked (E.I.) on the block OPL 93 relinquished by Mobil. At the time preceeding the drilling of Amenam -1 well, the Eastern Offshore Exploration team in Elf Nigeria was classically organised such that a pair of explorationists assigned to work on OPL 93: a geologist (T.D.) and a geophysicist (M.E.), directly responsible for the 2D seismic picking and geological interpretation, the preparation and follow-up of the Amenam exploratory and appraisal wells. The lower target of the exploration well was the H4 regional seismic marker emphasized by a strong impedence response considered to be the top reservoir. After having crossed 1700m of high pressured shales, the drilling was stopped due to operations after encountered very light hydrocarbon sand bearing reservoir. The success of the drilling was mainly due to the perseverance and the determination of the Chief geologist (D.N.) to reach the target whatever the difficulties and the business constraints. A side-track was performed, allowing to precisely locate the 9m. core after discussion with the sedimentologist (J.D.). Due to this and in applying new sequence stratigraphy concepts, a forced regression deltaic parasequence was recognized that successfully oriented the two following appraisal wells. In 1995, Mobil drilled KPONO exploration well bordering on block OPL 93 (OML 99) showing that the AMENAM deposit continued across the block OML 70 they operated. The AMENAM discovery became the AMENAM-KPONO major oil and gas field in 1998, consequently of the first ever unitization agreement realized in the Niger Delta (Elf, Mobil and NNPC) with initial reserves of nearly 1Bboe. This discovery was made by a team of Explorationists who believed in drilling a well to its technical limits and without any a priori in geological concepts . Amenam proved that most deep events offshore Niger Delta were not necessarily under compacted shales as deep seated unexplored structures on the onshore Niger Delta which hitherto were assumed to be.

AAPG Datapages/Search and Discovery Article #90332 © 2018 AAPG International Conference and Exhibition, Cape Town, South Africa, November 4-11, 2018