Hydrocarbon potentialityin NW Muglad basin using integrated seismic interpretation controlled by comparative study

Abstract

Integrated structural interpretation process of the reflective seismic data with wells data was conducted in Sufyan sub-basin, northwest Rakuba sub-basin in NW Muglad basin in West Kordofan State. Seismic data represented by two two-dimensional seismic lines, the study area is mainly covers a part of sufyan sub-basin and is surrounded on the southeastern side by Tomat high. The study aims to identify the subsurface structures in terms of tectonic movements and conduct basic comparison with previous similar study in Rakuba sub-basin. In this study, the interpretation processes were done using Petrel version 2009 and interactive petrophysics (IP V3.5) softwares. The interpretation was done for three formation tops: Aradeiba, Bentiu and AbuGabra formations, by tying and correlating them with Rabah-1_spliced well, then the existing faults were identified, and two-way time structural maps were created for three tops of these formations. Based on the interpreted seismic sections and generated structural maps, it was found that Sufyan sub-basin is an extensional rift basin. Two fault trends were observed: northwest-southeast fault trend which is the dominant faults in the study area especially in the middle part where sufyan sub-basin shows its maximum depth. The second recognized trend was the northeast-southwest faults trend which are observed in the southwestern part of the area. Integrated interpretation of the seismic sections and structural maps was calibrated with the well data and the stratigraphic column of the Muglad basin. The comparative study with Rakuba sub-basin indicates that the overall thickness of sediment was greater than in Rakuba, and the recognized faults in Sufyan were normal faults rather than the rotated faults that were mapped clearly in Rakuba sub basin. Beside Aradeiba formation is thicker compared to all Darfur group in Rakuba, the depocentre of Sufyan sub basin was mapped clearly although the limited number of seismic lines. Picking of all top interpreted formations in both sub basins was similar. The study recommends these points: interpreting more seismic lines calibrated with better well logging data from more wells to improve the vertical and horizontal extension of the sedimentary formations in Sufyan sub-basin, using integrated data to solve two ambiguities that are: Rakuba and Sufyan sub-basins were one sub-basin and separated later by dextral strike slip re-activated motion, and if the Tomat high is extended in the southwestern of Sufyan sub-basin?. Integrated available vertical seismic profiling data and checkshots would give more accurate and reliable extracted velocity values to convert the two-way times into true depths of top Aradeiba, Bentiu and AbuGabra formations