Midway through 2009, the exploration and appraisal spud tally stands at 21 wells, with a further 16 sidetracks started.
The numbers, while matching those of mid-2007, lag notably behind the 42 E&A starts to mid-2008.
The current total is evenly split between exploration and appraisal drilling, but the 10 rigs currently in action, an increase of two on previous reports, are predominantly engaged in appraisal programmes, with just three units active on exploration.
The semi-submersible, John Shaw, has switched temporarily to appraisal work in the Northern North Sea and the Ocean Guardian is back in the sector for a single well contract with Nippon in the CNS. The Leiv Eriksson has mobilised from Norway and will shortly be included in the statistics by drilling in the deep waters west of Shetland.
Once again, half the current activity is in the Central North Sea. Nippon spudded the Upper Jurassic Bowmore appraisal 15/24a-9 on June 20 with the Ocean Guardian, and with the Sedco 714 freed up from Jura duties, Total has again re-entered 30/1c-9 hole in order to test Kessog.
Nexen continues operations at Hobby South appraisal 20/1-10, where the northern extent of the Hobby structure is expected to see a further appraisal well drilled.
Talisman is 70 days into its Shaw near-field exploration well 22/22a-7, and CNR’s Deep Banff appraisal 22/27a-4 continues in sidetrack, the drilling of which was necessitated by downhole conditions requiring a deeper casing run.
GDF SUEZ’s Tesla exploration well 22/24c-11, which targeted a high-pressure/high-temperature Triassic prospect, was abandoned after a notably short duration of 60 days, including two weeks at total depth, but hydrocarbons were not found in commercial quantities. The efficient drilling operation will, however, have minimised well costs in this notoriously challenging HP/HT province.
In the Southern North Sea, the Noble Julie Robertson remains the sole active rig, spudding 48/15b-10 on the Rotliegendes Andrea prospect for Venture on June 11 after mobilising from the operator’s long-running Kew appraisal, 49/4c-7Z. The rig is set for a continued run of activity with Venture in the gas basin, its next contract extending to September, 2010.
A single appraisal well is active in the Northern North Sea, where the semi-submersible, John Shaw, is reportedly drilling an appraisal leg, 211/18a-S4Z, for Petrofac as part of the Don Southwest programme.
West of Shetland, Chrysaor continues operations on Solan appraisal 205/26a-8.
The drillship, Stena Carron, spudded a further Rosebank appraisal for Chevron; well 213/27-4 commencing on June 22 just 1.2 miles north-east of the 2004 Rosebank/Lochnagar discovery, 213/27-1,1Z. The drillship had mobilised from Hess’s Palaeocene Cambo appraisal, 204/10a-3, operated by Chevron, which was abandoned on June 21 after 33 days.
Chevron may drill its Aberlour prospect on block 213/28 using the drillship, possibly in 2010, after the vessel returns from a reported upcoming stint in deep Canadian waters.
The semi-submersible, Leiv Eriksson, was expected to spud, on July 2, Shell’s 214/21a-2, a re-drill of the abortive 2008 well on the South Uist Prospect.
In the East Irish Sea, the third well in the multi-well programme utilising Ensco 92 jack-up Challenger, 110/14d-8, was abandoned after about 15 days on the Triassic Crosby prospect and the rig has moved to spud Venture’s Marram appraisal on block 110/4.
The programme tally to date, which started May 1, shows a 33% hit rate.
Simon Robertshaw’s column is courtesy of drilling analysts Hannon Westwood LLP