Tiercelin, Jean-Jacques1, Michael Soreghan2, Didier
Granjeon3, Thierry Nalpas4, Delphine Rouby5, Stephanie
(1) Universite de Bretagne Occidentale, Plouzané, France
(2) University of Oklahoma, Norman, OK
(3) Institut Français du Pétrole, Rueil Malmaison, France
(4) Rennes University, Rennes, France
(5) University of Rennes, Rennes, France
ABSTRACT: Controls on Rift Stratigraphy Inferred from a Combined Seismic Stratigraphy and Stratigraphic-Modelling Approach: An Example from the Paleogene to Miocene Fluvio-Lacustrine Series of the Lokichar Basin, Northern Kenya Rift
The sediment fill of a non-marine rift basin is controlled both by the structural history of the rift as well as temporal change in regional climate. Structural and climatic controls on rift sedimentation are difficult to separate, however. Nevertheless, attempting to do so is important for developing models of rift sedimentation that provide a key exploration tool for the accurate prediction of the location, geometry, and character of reservoir and source-rock facies within ancient non-marine rifts. The Lokichar Basin of Kenya lies west of Lake Turkana, at the northern end of the Kenya Rift. The Lokichar Basin contains up to 7 km of basin-fill of Paleogene to Miocene age. In general, the basin consists of a relatively simple structural geometry, with a major basin-bounding fault on the western margin, and a flexural margin on the eastern margin. Using seismic data acquired by Amoco in the late 1980’s, combined with data from a single exploration well, we have defined six major seismic sequences and were able to map changes in depocenter location as well as changes in shoreline location. The well data; coupled with seismic facies analysis suggests that these sequences form transgressive-regressive fluvio-lacustrine packages. Our results suggest that sedimentation in the Lokichar Basin was controlled by both temporal changes in the location of fault motion along the major border system, as well as temporal changes in regional climate. The relative importance of these controls is being explored using a three-dimensional stratigraphic modelling program (DIONOSIS). From this model we can explore how variations in fault motion or climatic change potentially impacts basin-fill geometry including location and extent of reservoir facies.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.