Tullow announced on 24th September that the Cormorant Well in PEL 37 (Tullow Oil (35%), ONGC Videsh (30%) Pancontinental (20%), Africa Energy (10%) and Paragon Oil and Gas (5%)) will be plugged and abandoned. Since spud the Ocean Poseidon has been on location for only 20 days, some 2 weeks ahead of schedule.
Walvis Basin Licence Position with Prospects (Source MapStand)
Tullow’s press release announced the following
“The Cormorant-1 exploration well in Namibia has been drilled to a total depth of 3,855 metres and penetrated the objectives of the Cormorant prospect. Sandstones were encountered in the primary objective of the well but these proved to be water bearing. Wet gas signatures, indicative of oil, were encountered in the overlying shale section. “
Partner Pancontinental also reported that the well encountered a 50m gross section consisting of interbedded shales and claystones. The presence of wet gas shows above the reservoir does suggest that there is a working petroleum system in which case the most likely cause for failure is up-dip seal. As discussed in my article on the Cormorant Prospect, the up-dip seal towards the shelf was a critical risk, especially given the lack of a reported direct hydrocarbon indicator.
The Ocean Poseidon drill ship now moves onto to drill the S Prospect for the Chariot Group in PEL 71 (Chariot 65%, AziNam 20%, NAMCOR 10%, Ignitus Oil and Gas 5%). The S Prospect located on the southern margin of the Walvis Basin has gross mean prospective resource of 459 mmbbls and a probability of geologic success of 29% (source Chariot) and according to Chariot, the well has the potential to de-risk a portfolio more than 2 billion barrels of gross mean prospective resources.
Prospect S – Top Seal Depth and Channel Body Amplitude Extraction (source Chariot)
Prospect S – Seismic Over S Prospect (source Chariot)
The key difference between the S Prospect and Cormorant, is that it has a significant element of four way dip closure, probably caused by an underlying syn-rift igneous high. It therefore does not rely on the up-dip seal towards the shelf that may well have been the reason for failure in Cormorant. As with Cormorant no DHI has been reported by the operator.
Chariot are planning to drill the W Prospect in the event of success with the S Prospect.
Certainly a very exciting well and we wish Chariot and their partners every luck.
This blog represents the personal opinions and views of the author and does not necessarily reflect the views of MapStand