Structural, Environmental Deposition and Well Logs Studies of OML XY Block, Offshore, Niger Delta, Nigeria

Abstract

The concept of sequence stratigraphy in explaining sediment accumulation and preservation trends within basin fills has become a highly successful exploration tool in the search for hydrocarbon resources. The sequence stratigraphy of OML XY block, Niger delta study approach involved the integration of lithostratigraphy, seismic stratigraphy, and biostratigraphy to help unravel the depositional environment and petroleum play concept within the block. The block covers an area of about 400sqkm in shallow water between 2m - 45m. Thirteen (13) fields have been discovered to date, they include: - Akam, Kita Marine, Inagha, North Oron, Oron West, Oron East, Adanga, Ebughu, Bogi, Ukpam, Mimbo, Antan, and Ebne fields. It is also necessary to note that about seventy (70) wells have been drilled to date. This paper aims to understand the depositional environment and structural trend within the asset using 3D seismic data, analysis of wireline logs, and biostratigraphy analysis and how they aid in hydrocarbon accumulation, influence reservoir quality, and best describe the regional play concept within the block. Three predominantly prograding depositional sequences bounded by sequence boundaries were delineated. Biostratigraphy report indicates that sediment ages within the OML XY block range from Early Pliocene to Late Miocene. Depositional systems identified include prograding shoreline or delta and backstepping shoreline. The environment of deposition identified within the block range from upper to lower shoreface. Sedimentary deposits within the block include; marine shales, delta front sand, upper shoreface sands, lower shoreface sands, mouth bar sands, barrier bar sediments, and beach ridges sediments.