Field Study of Semiliki Sedimentary Basin

Abstract

The fieldwork was a period of 10 days, from 15th March, 2021 to 24th March,2021, in the Kibuku area of Semiliki basin, South and East of Lake Albert basin with the aim of studying the environments and processes of deposition of sediments in the area. The objectives were achieved through the use of software tools like Oasis Montaj, Sedlog, Techlog, well and seismic data. Semliki basin is structurally a half graben dominated by fluvial, deltaic and lacustrine sedimentary processes and deposits. The basin has sands, silts, clay and conglomerates as the four major lithologic units belonging to cross bedded sand facies, massive sand facies, clayey facies and conglomerate facies of middle Miocene to recent. The environments in the basin shifted over time from alluvial plain and fluvial channels, lacustrine, deltaic in semi-arid, humid and tropical climatic conditions. The rocks of Semiliki basin contain structures such as joints, faults, cross stratification, planar bedding, unconformity, foliation and many others. They structures exhibit a dominant NE – SW structural trend similar to the general structural trend of Albertine rift. The presence of oil seep in Kibuku confirms the presence of hydrocarbon in the subsurface. The well sorted sands of Kisegi, Kakara and Oluka formations are potential reservoir rocks; the huge clayey facies of Kasande formation are potential source rock and regional seal; and the intrasedimentary faults confirm the presence of a working petroleum system and contain hydrocarbon. However, we faced a challenge of poor weather condition and limited field time which made some places not to be visited. Basing on the challenges faced during the field project, I therefore, recommend the following; the field study should be conducted for the 14 days dedicated earlier for the project; more reading materials in the Library for the Petroleum Geoscience program and more training to be conducted on how to use Geoscience software.