Five exploration and appraisal wells are currently operating on the UKCS from two semi-submersible rigs, two jack-up units and a single drill ship. That’s all.
Over the year to date, 11 wells comprising three exploration spuds and a sidetrack, four appraisal spuds and three sidetracks have been started.
A marked differential is observed between the number of mobile rigs on E&A activity versus production/development drilling, with almost four times as many mobile units – some 19 rigs – working on the latter.
And just about 10% of current production/development drilling is being conducted from platform-based facilities – in marked contrast with times past.
In the deepwater West of Shetland area, Chevron’s Lagavulin prospect, well 217/15-1, is belatedly confirmed as a mechanical sidetrack, kicking-off on January 22 from the Stena Carron drillship. The initial hole was abandoned after 110 days and the sidetrack was 90 days in and counting at the time of writing this column.
In the Northern North Sea, the semi-submersible Sedco 714 remains on station at Total’s 3/15a-14 well being drilled on the Oban prospect. It is one of two 2010 well starts still active, having spudded on the penultimate day of last year.
The Transocean Prospect semi continues working for Sterling on Cladhan, where well 210/30a-4 was plugged and abandoned as a successful appraisal, prior to starting geological sidetrack 210/30a-4Z in mid-April. The rig is positioned so as to reach three targets from a common surface location, with the initial leg looking to test an eastern extension but failing to establish the elusive oil-water contact so that the effective vertical oil column remains for the time being at a minimum of 374m (1,228ft).
With completion of EnCore’s well 28/9-4Z and subsequent release of the Galaxy II jack-up, Central North Sea activity currently stands at two wells. That Burgman appraisal leg was abandoned after seven days, Initial estimates of oil in-place were indicated at between 80 and 100million barrels – a valuable addition to Greater Catcher.
Maersk completed its initial geological sidetrack on the HP/HT (high pressure/high temperature) Culzean accumulation and initiated a second geological sidetrack, well 22/25a-10Y, towards the end of March again using the jack-up Ensco 101.
BG well 30/2a-8, an appraisal of Jackdaw and utilising the Gorilla VI jack-up, is understood to have been operating at total depth for some weeks. This is the second of the two still active 2010 well starts, having been spudded back in early August.
Temporarily devoid of E&A drilling is the Southern North Sea, following the abandonment of Sterling’s unsuccessful Grian prospect well 48/28b-2, which was drilled using the Ensco 80.
Q1 2010 saw no activity in the Irish Sea Basin. That is still the case.
While well starts to date are markedly lower than at this time last year – by which time 12 spuds were noted – at least the results have been good, with more good news expected from current drilling.
Exploration & appraisal success rates for 2010 are already in excess of 50%. Quality not quantity might be an appropriate to describe such a result.
A raft of rig contracts and drilling programmes currently feeding through the system should result in a notable jump in activity levels as the year progresses.
Simon Robertshaw’s column is courtesy of North Sea drilling analysts Hannon Westwood
Recommended for you
