Journal of Geology & Geophysics
Open Access
ISSN: 2381-8719
ISSN: 2381-8719
Chuku Hope Chibuzor and Odigi Minapuye Isaac
University of Port Harcourt, Nigeria
Posters & Accepted Abstracts: J Geol Geophys
The understanding of the sedimentary processes of the sea floor is very integral to subsea facilities development in oil field within offshore province to obviate problems related to instability and drifting of drilling rigs, collapse of offshore structures including production platforms, grounding of operations vessels and pipeline ruptures, with concomitant spillages. This study of the EMOBS fields (comprising of five fields) in the shelf environment of western Niger delta Nigeria, with combined results from measurements using high fidelity onboard instrumentation and data from existing well cuttings have helped in determining the implications of sedimentary processes on subsea facilities in the fields. Bathymetry ranges between 5-18 m, 15-17 m, 8-6.8 m, 18- 20 m and 18-31 m water depth respectively with a deepening trend from the north to south end. The seafloor topography generally is undulating in the north to gently flat in the south caused by ripple currents and storm processes. The sediments from the sea bed scan vary from silty clayey sand through clayey silty sand to sandy silty clay. The strong seismostratigraphic interface (lithified sediments-competent bed) depth below the seabed ranges 4.5-5.5 m, 3.5-4.5 m and 2.5-5.0 m as corroborated by the sediment analysis of the well cuttings which show the presence of sandstone at 2-6 m and two paleo-channels separated from each other by flood plain deposits, marked by a coarsening upward facies sequence. Gas charged sediments about 15-20 m thick occurs between the seabed and the lithified layer. The sea floor scan also shows existence of genetically related depressions and surrounding rings of sand called pock marks which vary between 0.5-9 m in diameter. Based on the findings, a number of recommendations have been formulated for the safe and cost effective development of this oil field.
E-mail: hopechibuzor@yahoo.com