Aberdeen-based independent Venture Production has brought Annabel gasfield onstream, located 100-km off England's Lincolnshire coast in the Southern North Sea. The original discovery well, 48/10a-12, was developed as a 17-km subsea tieback to the Venture-operated Audrey A platform.
The exercise involved what the company claims was the first hydraulic fracture of a subsea well anywhere in the UKCS, generating a three-fold improvement in productivity of the Lower Leman reservoir section. Initial output is in line with expectations, at 60-70 MMcf/d, with production exported through ConocoPhillips' Loggs pipeline system to the land-based Theddlethorpe terminal. Venture aims to start shortly on a second development well for the field. Estimated reserves from the two wells are 96 bcf.
Venture issued details on its other UK North Sea developments in its latest financial results briefing. Production from the "Trees" fields in the north of the sector rose slightly last year, despite a shutdown last November caused by a gas leak in a 4-in., service line associated with Marathon's host Brae A platform. A water injector on Sycamore did not produce the expected results; the well penetrated the reservoir section, but proved not be in communication with the production well at that location. However, a successful workover on the main Birch production well Z3, which was shut-in since December 2000, has offset lower output from Sycamore.
Venture plans to drill a second water injector on Sycamore this summer, and has brought forward phase 3 of the development to this year, following agreement with CNR to drill a new production well from the latter's Tiffany platform. The original, more expensive plan, had involved drilling the well as a subsea tieback to the existing Trees infrastructure. Larch's productivity was also raised through the restoration of high-pressure gas-shlift. Following a further equity transaction, Venture has now assumed 100% control of Trees block 16/12a, and is looking to drill several untested exploration prospects, such as Ash and Cedar.
In the Greater Kittiwake Area in the Central UK North Sea, Venture and partner Dana are in the final stages of development planning for the Goosander, Whinchat ,and Wagtail fields. Development will be phased, with Goosander likely brought onstream 2006, followed by the other two in 2007, assuming successful appraisal drilling. The host in each case will be the Kittiwake platform, using a combination of subsea production and gas-lift flowlines
Finally, Venture will likely revert to a floating production and storage solution to develop the Chestnut oilfield in block 22/22a. This problematic field has been extensively appraised, initially via an extended well test, with discussions in recent years veering towards a tieback to a third-party platform, such as BP's Andrew. A final development plan and project sanction are expected later this year, leading to first oil in 2007.