Shell is back in the Nelson area. Not to test another Paleocene prospect, but to try and prove hydrocarbons in the Upper Jurassic pod/intra-pod area east of Nelson through drilling two exploration wells.
The company is not new to the play; it previously developed the nearby Upper Jurassic Howe and Bardolino fields, with mixed results. As shown clearly in this paper, the Howe field is an example of a successful Fulmar development with a delayed water breakthrough, whilst the Bardolino field has disappointed from the start with water production taking place immediately. As a result, Bardolino has not produced any more since 2015 whilst Howe is still going strong.
So, on the basis of this experience, the Shell team will no doubt hope that the wells on the agenda now will prove the Bardolino field to be an anomaly in terms of suggested fault sealing mechanism causing compartmentalisation.
Jaws
The first well that is currently being drilled is 22/12d-13 testing the Jaws prospect in P2380. Named after the character who played in a couple of James Bond films in the 1970’s, Jaws forms an Upper Jurassic Fulmar prospect that relies on trapping against (fault-bounded) Triassic Smith Bank mudstones. According to Energy Voice, the size of the prospect is up to 30 MMboe.
Apache relinquished the licence covering the Jaws prospect in 2011, claiming that “technical evaluations failed to develop this lead as viable drilling prospects during the primary term of the licence,” whilst geological analysis of analogue plays identified reservoir presence as the critical prospect risk.
Apache also identified a second prospect just north of Jaws, which they named 22/12-JU3 – not a James Bond character presumably. This slightly shallower structure was thought to be prospective in the Upper Jurassic too, but in this case Kimmeridgian turbiditic sandstones were interpreted to be the main target. Given that well 22/12b-4 immediately south of 22/12-JU3 drilled water-bearing Fulmar sandstones, the slightly younger Kimmeridgian sands in the prospect would require pinching out towards the south.
Orlov
Following completion of 22/12d-13, there will be a short break – a break during which the Edinburgh well might be drilled – before Shell returns to the area next year to drill the Orlov prospect in P2377. As presented at Petex last month, Shell is still open for farm-ins to participate in drilling this structural trap targeting another Fulmar reservoir. The company expects a recoverable volume of 5 to 15 MMboe, with the largest uncertainty being the column height determined by the lateral seal.
HENK KOMBRINK
