Stratigraphic and structural interpretation of seismic sections in Lokichar Basin

Abstract

This research was carried out in Lokichar Basin located in Turkana County in Northwestern Kenya. The study area is within the Tertiary Rift Basin of the four sedimentary basins of Kenya which include Lamu, Anza, Mandera and Tertiary Rift basins. Lokichar basin consists of relatively simple structural geometry with a major basin-bounding fault on the western margin called Lokichar fault, and a flexural margin on the eastern margin. The present investigation involved the interpretation of old secondary seismic sections in order to come up with a subsurface structure with an aim of identifying and delineating possible hydrocarbon traps and prospective areas. Five lines of 2D seismic data from Lokichar basin were interpreted. Data analysis and interpretation was done using SMT Kingdom Suite vers 8.6 software. The interpretation process involved picking and tracing of horizons and faults of interest from the vertical seismic displays of the seismic lines. Interpreted results have confirmed that there exists a major bounding fault called Lokichar fault on the western side of the basin. The fault could be responsible for controlling sediments deposition within Lokichar basin. Lokichar fault was determined to be generally a normal low angle fault that dips towards the east. Similarly, most of the other faults interpreted were found to be mostly high angle, listric in nature and generally dipping towards the east. Positive and negative flower structures were found to be common in Lokichar basin. Structures that control hydrocarbon accumulation and trapping were identified to be fault closures and fold anticlines. These structures could therefore form the target areas for hydrocarbon prospecting. On the interpreted seismic lines, hydrocarbon prospective areas were estimated based on the results of Loperot-1 well.