The global recession and oil-industry slowdown are biting deeper into the North Sea as the number of rigs drilling exploration and appraisal wells has dropped by three since the April WellSlot.
There are only eight mobile rigs currently active in the UK sector. Of these, four are drilling sidetracks and one is nearing the end of re-entry duties.
All but two are working in the Central North Sea.
Nexen has two rigs active on block 20/1: one working on the third sidetrack of well 20/1-8, appraising the promising Hobby discovery, the other appraising well 20/1-9 – last year’s Jurassic Pink discovery, which now has its own special sub-area within the block.
Both Hobby and Pink are located in Jurassic age sediments.
Talisman started operations on Shaw exploration well 22/22a-7 on April 20, the Ocean Nomad also chasing a Jurassic target.
CNR’s high-pressure/high-temperature Deep Banff appraisal well, 22/27a-4, which spudded early-January, should be at, or close to, reservoir depth.
Operations on Shell’s Fram appraisal 29/3c-8Z are nearing completion following a test programme in the Palaeocene sands.
Operations on Total’s 30/1c-9, which was re-entered in March for an extended well test on the Kessog discovery, are also coming to a close as the well suspends. The rig working on that well, Sedco 714, is moving to production duties in support of the Northern North Sea Jura field.
Also during April, Talisman suspended its 22/17-4Z well following a programme of a single exploration well which registered a Jurassic discovery on the Godwin prospect and an appraisal sidetrack that lasted 155 days.
A single well is active in the Southern Gas Basin. Venture’s 49/4c-7Z, appraising the Rotliegendes Kew discovery, was sidetracked in early February following four weeks of operating at total depth in the initial hole.
GDF SUEZ abandoned its second back-to-back Cygnus appraisal well, 44/12a-4, after 54 days following a test programme in the Rotliegendes Leman sandstone which flowed 32million cu ft of gas a day – which rate is in excess of pre-drill expectations.
Together with the previous well, 44/12a-3, this has confirmed the potential of a total of three related fault-blocks.
As one of the largest undeveloped gas discoveries in the Southern North Sea, a phased development on the proven eastern portion of the complex structure is expected to go ahead. Further potential remains to be appraised to the west.
Up in the Northern North Sea, well 211/19a-M75Z, which was deviated from the Murchison platform into the Norwegian sector to test the Delta prospect, was abandoned after 116 days, including 25 at total depth.
No comment has been forthcoming from the field’s operator. However, the borehole has been retained to drill a development leg, though whether this will be on Delta or as an infill production well on Murchison is yet to be revealed.
West of Shetland, Chevron’s long-running Rosebank North exploration well was kicked off on sidetrack 213/27-3Z in mid-April. The original well was abandoned after 154 days, with three weeks spent at total depth. A positive outcome seems likely.
Looking to the future, the multi-well programme with the Ensco 92 in the East Irish Sea is expected to begin soon, with back-to-back drilling of two wells in blocks 110/12 and 110/13 for EOG.
Simon Robertshaw’s column is courtesy of North Sea drilling analysts Hannon Westwood LLP
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