Stratigraphy of "Efi-Field" oil deposit of Niger delta on-shore region
The Niger Delta is one of the richest hydrocarbon provinces in the world. The geological structure of Niger Delta is composed of Mesozoic and Cenozoic rocks. Modern Niger Delta has distinctive basin-like geological structure that is defined by inner extensional zone of listric growth faults beneath the outer shelf, translational zone of diapirs and shale ridges beneath the upper slope, and a lower compressional zone of toe thrust structures. The delta comprises of three broad formations, namely: the Benin Formation (Oligocene to recent), Agbada Formation (Eocene to recent) and the Akata Formation (Paleocene to recent). The “Efi-Field” deposit is composed of rocks of the Cenozoic age. The geological section of the field starts from Paleogene (P1-P3), Neogene (N2) and Quaternary periods. The Cenozoic deposits are represented by rocks of the Paleogene, Paleogene-Quaternary and Quaternary periods. The prevalence along the territory is very uneven. Close to the axial part of the Niger Delta, Quaternary sediments predominate, sometimes with sedimentation of some stratigraphic subdivisions of the Cenozoic period. Sedimentation was formed under conditions of Cenozoic local regression of the ocean, as a result of which the base of the section is represented by marine geological-genetic types of sediments, and the middle and upper parts by transitional coastal-marine types of sedimentation.