The Niger Delta Oil Province covers about 40,000 square miles which are underlain by thick deltaic deposits of Tertiary age. These deposits have been subdivided into three formations: at the surface the continental, sandy Benin Formation, deeper down the transitional Agbada Formation of alternating sands and shales, and finally the marine, shaly Akata Formation.
The principal oil discoveries have been made in the Agbada Formation.
These accumulations are controlled largely by growth faults and roll-over anticlines which are found primarily via seismic surveys. Exploration drilling on these structures has been highly successful with 136 discoveries out of the 261 wildcats drilled for Tertiary prospects by mid-1966.
Subsequent development drilling has proved equally encouraging, and the most productive onshore field, Bomu, and the first commercial offshore field, Okan, are described. Both fields have active water drives and production per well averages about 3,000 b/d. Production in Nigeria has risen from 5,100 b/d in 1958 to 350,000 b/d during the first half of 1966, and it is expected that the daily rate will exceed 500,000 barrels before the end of 1966.
Parallel to this production build-up exploration activities are foreseen to continue at a high level not only in the Niger Delta Oil Province, but also in the area of possible Cretaceous prospects bordering on the actual delta.
Les accumulations pétrolifères actuellement connues dans le Delta du Niger se trouvent dans les formations tertiaires d'origine deltaïque. Les principaux pièges pétrolifères sont constitués par des "growth faults" associées à des structures en "rollover". L'outil d'exploration le plus efficace, pour détecter ces pièges est le sismographe. Plusieurs reconnaissances géologiques et géophysiques ont abouti au premier forage profond en 1951, et à la première découverte commerciale en 1956. Au large des côtes, le premier forage d'exploration était exécuté en 1963, et suivi par la première découverte commerciale en 1964. La production des champs terrestres commença en 1958 et celle des gisements marins en 1964. A la fin de l'année 1965, l'exploitation produisait quotidiennement environ 365,000 barils d'huile.
A string of sedimentary basins occurs along the west coast of Africa, in most of which marine deposition by E. J. FRANKL Shell-BP Petroleum Development Company of Nigeria, and E. A. CORDRY Nigerian Gulf Oil Company commenced sometime in the early Cretaceous. The largest of these basins is the Southern Nigerian Basin, part of which is occupied by the Niger Delta (Fig. 1).
Three major cycles of sedimentation have been established in the Niger Delta and its hinterland: The oldest extends from Albian to Santonian time.
The next one lasted fro