Methodologies for Reservoir Prediction South Angola

Kelly Papesh¹, Liz Allison¹, Anthony Sprague², Steve Keidel³, Vicki Springer^l, and Sebastiao Domingos^4
1 ExxonMobil Exploration Company, Houston, TX
² ExxonMobii Upstream Research Company, Houston, TX
³ ExxonMobii Development Company, Houston, TX
⁴ Esso Exploration Angola (Block 15) Limited; Luanda, Angola

Reservoir presence and quality were considered major risks in the Benguela/Kwanza Basins at the time the blocks were tendered in South Angola. No Cretaceous well penetrations existed within the basin. Several tools and methodologies were utilized to define sedimentary pathways. Detailed regional mapping followed by the use of amplitude extractions and horizon/proportional sculpting led to the delineation of sand fairways. These results were then considered in conjunction with present day structure maps and hydrocarbon systems maps to identify key traps.

The success of these methodologies will be demonstrated in more detail using the results of the first three wells. One of the first wells targeted a stacked sequence of Confined Channel Complexes and found excellent quality sand. The other two wells drilled into Distributary Channel Complexes with only one of the two finding reservoir quality sands.

Results from these wells suggest the identification of feeder channels are critical in de-risking reservoir presence in basins where little to no well control exists. Where feeder channels could be identified, significant amounts of sand were found; where they were difficult to identify or absent, sands were not found.