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wreck,” says Joost Perquin, director of

International Strategy Offshore Services,

Tetra Technologies. “We have to be cog- nizant that not all wells are the same,”

P&A he told the June’s 2014 Decom Offshore

EyebrowProduction conference in Aberdeen.

Perquin puts wells into four catego- ries, according to their abandonment complexity. Category one are wells problems with good integrity and no limitations.

P&A is expected to amount to 43% Category four wells have had sustained

Plugging and abandonment of the overall estimated decommission- casing pressure due to hydrocarbons or accounts for about 43% of ing costs, according to an Oil & Gas UK overpressures, or are without cemented decommissioning costs. Operators survey conducted last year. A total 5000 casing at barrier depths. wells are expected to require P&A on Of the 300 central and northern North and service companies are looking the UK Continental Shelf (UKCS). In just Sea platform wells, he says, “some— at ways to reduce the bill. Elaine the next 10 years, some £4.5 billion is one in four, or 20%, anecdotally—are

Maslin reports from the 2014 expected to be spent on P&A operations a “train wreck” (category four). 50% on about 800 wells, 480 in the central have good integrity (category one) or can

Decom Ofshore conference.

and Northern North Sea, and 300 of those be accessed through coiled tubing or a on platforms, according to Oil & Gas UK’s hydraulic work over unit (category two).” sing 15 rigs full time, it would 2013 Decommissioning Insight. The costs can be high. An average cat- take 40 years to plug and egory one well costs about £2.1 million to

U “Train wreck” wells abandon (P&A) all the current P&A, rising to £9.3 million for a category 3000 and expected future wells on the A major part of the challenge is the four well, he says. Category one wells

Norwegian Continental Shelf. condition wells are in. Not all wells are take about seven rig days and category

It’s a striking statement, made earlier the same and one in four are a “train four 31 rig days, Perquin says, with the this year by Martin Straume, lead P&A cost of using a rig for P&A operations

P&A cost comparison table engineer for BP in Norway and chairman standing at about £300,000/d.

Equipment needed: Double drum wireline unit, of Norway’s Plugging and Abandonment So what can be done? Straume’s com- cement blender, pump and PU, a storage tank,

Forum (PAF), under industry body ments were made to highlight the size of plus auxiliary equipment. A nine-man crew for

Norwegian Oil and Gas. the P&A challenge, and incite the supply 24-hour operation.

The UK sector is facing a similar chal- chain to fnd ways to fnd new rigless

Gulf of UK lenge. The overall decommissioning bill solutions to make the process more

Mexico North Sea for the UK North Sea has been estimated effcient and cheaper, and free-up rigs for

Spread rate per day US$35,000 £100,000 at about £35 billion, but “on recent well E&P drilling.

Consumables per $30,000 £75,000 abandonment performance, costs could Perquin agrees, and suggests fnding well escalate and easily exceed £50 billion,” alternatives to using a mobile drilling

Time needed 4-5 days 6-7 days according to Sir Ian Wood’s UKCS Maxi- rigs for P&A operations, such as using lift

Total P&A cost* $200,000 £750,000 mizing Recovery Review, published in boats, subsea P&A, platform-based rigs, *Excludes overhead and support cost

February. or using a dive support vessel (DSV) or utility based boat—all already used for

P&A operations outside the North Sea, he says. “Rigless P&A can be done on the platform or off a lift boat, jackup, or DSV.

You can also get access to subsea wells through riserless intervention,” he says, adding that it is already being done in the

Gulf of Mexico. Perquin set out a rigless

P&A cost comparison between the UK and Gulf of Mexico, see table.

Alternatives

Companies are marketing alternatives.

A joint venture between Malaysia-based

Bumi Armada and Fugro (51%/49% respectively) has introduced the Fugro

Synergy as a well intervention vessel, which could “take P&A off the criti- cal path” and free up rig time, Mitchell

The .Fugro Synergy From Fugro Drilling and Well Services

Pinkard, business development manager,

August 2014 | OE oedigital.com 84 000_OE0814_ProdOps2.indd 84 7/23/14 12:39 AM