A geological and geophysical field study of kibuku area, semliki basin, albertine graben, western Uganda.

Abstract

A field work and excursion study to Albertine graben under the guidance of our lecturers during the recess term of our third year of study for 14 days. The area of study was Semliki basin located in the southern part of Lake Albert in Uganda. The study area lies onshore south of Lake Albert,it is bounded by escarpments to the east and south and River Semliki to the west. The aim of this study was to enable students to study the environments and processes of deposition of sediments in Semliki basin as well as understanding the physical, sedimentological and sequence stratigraphic formations in the region. Litho-stratigraphic logging and interpretation, together with structural and stratigraphic data collection and interpretation were carried out to make conclusions about the petroleum potential of Semliki basin. Sandstones, clay stones, siltstones, peat and conglomerates were identified as the facies in Kibuku and their role in the basin's petroleum system as source rocks, reservoirs or seals were established. The basin was affected by intensive tectonic activity, that led to formation of vast types of structures with in the basement and sediments that were observed. Examples of these structures include faults and folds. Sedimentary structures such as unconformities, pinch outs, lenses, sandbars, bedding, cross-bedding and concretions were observed, their significance as stratigraphic traps and or paleo flow indicators deduced. The presence of hot springs with in the study area indicates the presence of a high enough geothermal gradients for source rock maturation. Studies about the Turaco wells and the Kibuku oil seep confirmed presence of hydrocarbons in the Semliki basin and are evidence of a working petroleum system.