Page 47: of Offshore Engineer Magazine (Sep/Oct 2016)

46 48

PRODUCTION was subsea and not downhole, so the sitting 200km northeast of Aberdeen expectations year-on-year,” Preece said. subsea control module was replaced us- in 140m water depth, is a very dif- In total, there are now 47 platform wells, ing a dive support vessel (DSV). ferent asset, said Rachel Preece from plus nine subsea wells on Britannia,

While the operation to add new per- ConocoPhillips, at Devex. With asset three on the Brodgar ? eld, four on forations on well 131 was held up due to maturity and increasing third-party pro- Callanish, and one on Enochdhu, with solids in the well, contingencies put in cessing complexity, both parent compa- Alder due later this year. But, while ~2.6 place for scale wash and milling helped nies embarked on an asset performance Tcf of the 4 Tcf in place in Britannia has the project go forward. Gas lift was then review in 2015 resulting in the recom- been produced, and some plugging and successfully retro? tted using a LWI. On mendation for a new operating model. abandonment work started last year,

The Britannia ? eld, one of the larg- the second stuck downhole safety valve, Preece says that there is still some way est gas condensate ? elds on the UK the hydraulics were ? xed using a DSV. to the ultimate recovery goal. Last year,

Continental Shelf, was discovered in 1975 “Unfortunately, well 131 didn’t clean production was about 200 MMscf/d.

by Conoco, now ConocoPhillips. Yet, it up as much as we had hoped, but com- “As production from the platform declines, we still have some tricks up our didn’t come onstream until 1998. It wasn’t bining it with the fact that we came in sleeve as we move towards late life strate- until 1990 that the ? eld was con? rmed well under our P50, the economics are as a single accumulation – by which still favorable, the pay back is just a bit gies,” she says. “Our focus is on effective time some 22 wells had been drilled by longer,” McKevitt says. reservoir management and production multiple operators. The ? eld was named in

Key to delivering the project was tak- optimization techniques, including the 1991, in 1994 the ? eld equity was agreed ing a step-by-step approach, managing use of an offshore petroleum engineer to and the ? eld development was approved.

risk and cost exposure through phasing optimize well uptime and LTC.” the project activities and pre-planning At the time, Britannia was the largest There have been plenty of challenges contingency options, McKevitt says. substructure in the North Sea. It had with lessons being learned on the way.

Most crucial was being able to retro? t the longest ? owline tieback and was The asset spans four blocks and sub- gas lift off a LWI, something which BP the ? rst to use heated carrier bundles to blocks, and without a single operator, had never done before. prevent hydrate formation. it was dif? cult to ? nd focus for this

The ? eld came online in 1998, via an cretaceous gas condensate develop-

Late life planning eight-legged jacket topside. Two years ment. “Through targeted acquisitions,

The Britannia facility might be moving later plateau production was reached at we reduced the number of co-venturers into a late life phase, but operator ~800 MMscf/d, meeting some 8% of UK from over 30 to three, and with our

ConocoPhillips continues to look for ways gas supply at the time. subsurface understanding being key to to extend its life, aided by a renewed

Yet, that was just the start for the asset value, we are now continuing business focus.

Britannia. In 2008, the Britannia to test new methods to further develop

Britannia was operated through

Satellites (BritSats) project started up, this,” Preece says.

Britannia Operator Ltd. (BOL) – a involving the fabrication of a four-legged Having a joint operating company joint operating company and the ? rst bridge-linked platform to the main facil- meant getting the best at the time from of its kind in the North Sea – with ity, to tie in the Brodgar and Callanish the two international operators. Now,

ConocoPhillips and Chevron as the 50:50 ? elds, with Enochdhu added in 2015, and with ConocoPhillips becoming operator owners. However, in August last year, the Britannia Long Term Compression and the move to an integrated opera-

ConocoPhillips acquired the shares (LTC) module (currently the UK’s larg- tions strategy, it has further reduced from Chevron, and BOL (now known est low pressure compression module) complexity and succeeded in a 10% as ConocoPhillips (UK) Britannia Ltd.), in 2014. This year, ? rst production is opex reduction in Q1 2016, Preece says. became a wholly-owned subsidiary of expected from the Alder high-pressure But, the reservoir management strat-

ConocoPhillips.

high-temperature ? eld, a new tie-in. egy continues and the company is still

Discovered 41 years ago, Britannia, “Britannia production has exceeded looking at in? ll drilling and near? eld opportunities.

BP’s ETAP facility. Photo from BP.

The Britannia story, like Monan, will continue.

The Skandi

Constructor, used on the BP Monan project. Image from

Helix Energy Solutions. oedigital.com September 2016 | OE 49 048_OE0916_Production2_elaine.indd 49 8/24/16 4:38 PM