f Relationship Between Gas (CO2) Traps And Structural Styles In The Al Jamouse Area, Melut Basin, Sudan

One of the recent exploration challenges in the continental rift basins of Sudan is the flushing effects<br>of hydrocarbon (oil) from the structural traps by carbon dioxide (CO2). This presentation will show some<br>examples from the most prospective traps in the Melut basin (half graben basin) (Fig.1) of Sudan that proved<br>this phenomenon. These prospects were originally categorized as the high rank drilling candidates in term of<br>the size and petroleum system elements (source rock, reservoir rock, trap, migration, timing…etc).<br>During drilling, good and continuous hydrocarbon shows were encountered along the targeted<br>reservoir intervals of the Adar and Yabus/Samma sands (Tertiary Reservoirs) in the kitchen area (Fig.2a).<br>However, the formation evaluation (e-log) confirmed that the zones were gas bearing (from the densityneutron<br>cross-over and pressure gradient plot) (Fig2b). Production tests were performed on the potential gas<br>hydrocarbon zones. The tests results concluded that the reservoirs were filled with carbon dioxide (CO2) rather<br>than hydrocarbon gas bearing (up to 90% CO2). As the result, the prospectivity of this area was downgraded<br>and the exploration strategy was subsequently changed.