Modelling of Petroleum System Structures by Use of Gravity and Seismic Data in Kerio Valley Basin, Kenya
No Thumbnail Available
Date
2021
Authors
Sila, Faith
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
Kerio valley basin is one of the sedimentary basins in Kenya known to have hydrocarbon formation potential. Exploration is ongoing in the area with different geophysical methods being employed. The possible existence of significant hydrocarbons has led to increase investigating the structures developed interest in geological structures and basin modelling. This research utilized 2D seismic and gravity data with the aim of determining density variation within the basin, their characteristics and model geological structures of Kerio Valley basin. Gravity data collected in the basin was processed and interpreted using Golden surfer 8 to provide information about rock density contrast for the sedimentary layers. These sedimentary layers form from deposition and compaction of rocks due to pressure as the basin evolved. Data was uploaded in Euler deconvolution software with structural index of 1.0 and 0.5 in window size. It was again loaded in Grav2dc for forward modelling and the average density contrast values used were 2.2g/cm3, 2.5g/cm3, 2.28g/cm3 and 2.6g/cm3 respectively from the top to the deepest stratigraphic layer formed due to deposition and compaction of different rocks over a period of time. Seismic data was interpreted using PetroMod software, the value used for heat flow was 68Mw/m2 and paleo water depth were and 68m,112m,700m,840m and 900m as model input. Over a long period, the basin passed through tectonic regime and transformed into a sedimentary basin. ID model showed that the source rocks are mature and have potential to produce hydrocarbon as shown by vitrinite reflectance. Temperature curves show that temperature was maximum during Miocene volcanics and has been decreasing over a period of time. Gravity data analysis showed that there are high gravity anomalies at the western and eastern sides, low gravity anomalies at the centre of the basin and the sedimentation is constrained by two major faults. The basin is underlain by a deeper basement which is overlain by interbeds of sandstones and volcanoes. Seismic reflectors showed discontinuities which may be caused by lava flows. The deepest reflector showed the deep sedimentation in the basin. Geological structures necessary for hydrocarbon formation are present
Description
A Thesis Submitted as Partial Fulfillment of the Requirement for the Award of the Degree of Masters of Science (Geophysics) In the School of Pure and Applied Sciences of Kenyatta University.
November, 2021
Keywords
Petroleum System Structures, Gravity, Seismic, Data, Kerio Valley Basin, Kenya