Page 17: of Offshore Engineer Magazine (Sep/Oct 2016)

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FIELD OF VIEW at the top (“attic oil”), as well as a waxy interface between the oil and ballast water, sediment (containing sand ? ushed in

Rig stats during a gas blow down in the 1990s) and ballast remain in

Worldwide them. But, access is limited, so new technologies had to be

Rig Type Total Rigs Contracted Available Utilization developed to reach the contents.

Drillship 99 68 31 68%

One of the ? rst attempts to access the sediment was with

Jackup 396 244152 61% tractor technology. But, onshore trials found the tractor would

Semisub 122 85 37 69% not be able to navigate the 90° corners of the ? ller lines into 31 21 10 67%Tenders the cells. Shell then started a program to access the cells from

Total 648 418 230 64% the outside, which would mean boring through the 1m-thick

North America reinforced concrete cell shells.

Rig Type Total Rigs Contracted Available Utilization

A number of contractors were engaged to deliver the pro- 30 26 4 86%

Drillship gram, and in 2014 their combined efforts resulted in the ? rst 25 5 2020%

Jackup cell sampling. Divers connected a base plate to the top of three 14 9 5 64%

Semisub

Delta cells, some 80m below the waves but accessible from the

N/A N/AN/A N/A

Tenders platform crane. A lubricator tool was then attached to the base 69 40 29 57%

Total plate, through which a sampling tool could be sent.

Asia Paci? c

Shell then hired Enpro, which built upon the original concept,

Rig Type Total Rigs Contracted Available Utilization creating a smaller, lighter, simpler and entirely ROV-operable sys- 9 4 5 44%

Drillship tem. To make operations for the removal of the attic oil easier, as

Jackup 118 67 51 56%

Shell didn’t just want to sample the sediment and attic oil, it also

Semisub 29 16 13 55% wanted to remove the latter, a big, innovative move was made; 22 14 8 63%

Tenders

Shell cut a hole right through the center of the platform, to create 178 101 77 56%

Total a moon pool, to ease access to tops of the cells.

Latin America “To cut a moon pool from the top deck, through the cellar

Rig Type Total Rigs Contracted Available Utilization decks, allows us to effectively deploy the attic oil recov-

Drillship 28 19 9 67% ery tools far more effectively than doing it over the side,”

Jackup 50 32 18 64%

Manning says. Over the summer, the tool has been remov- 23 20 3 86%

Semisub ing the attic oil from the Delta cells, helped by ROV operator 2 2 0 100%Tenders

ROVOP, with a platform-based ROV.

Total 103 73 30 70%

North Sea calling NASA

Northwest European Continental Shelf

Rig Type Total Rigs Contracted Available Utilization

But, while the external access tooling was being developed, 1 0 1 0%

Drillship

Shell was also working with NASA on a probe that could

Jackup 49 38 11 77% go down the ? ller lines. “We have a technology partnership

Semisub 39 31 8 79% with NASA and we reached out to them,” Manning says.

Tenders

N/A N/AN/A N/A

NASA came up with a tool, a 9in-diameter sphere contain- 89 69 20 77%

Total ing miniaturized sonar equipment, which could be ? ushed down the 10in-diameter ? ller lines into the cells to map their

Middle East & Caspian Sea

Rig Type Total Rigs Contracted Available Utilization insides. The spheres are attached to a tether and pulled out 1 0 1 0%

Drillship once they’ve completed their mapping. “It is technology they

Jackup 112 84 28 75% adapted from the technology they use on the space shuttle to 4 3 1 75%

Semisub understand the internal pipework condition,” Manning says.

N/A N/AN/A N/A

Tenders

It took a series of attempts to get it to work, the ? rst on Delta,

Total 117 87 30 74%

A CGI illustraton of the Brent ? eld. Image from Shell.

Sub-Saharan Africa

Rig Type Total Rigs Contracted Available Utilization 17 13 4 76%

Drillship 20 10 10 50%Jackup 5 3 2 60%

Semisub

Tenders 7 5 2 71%

Total 49 31 18 63%

Eastern Europe

Rig Type Total Rigs Contracted Available Utilization

Drillship 1 1 0 100%

Jackup 2 1 1 50% 1 1 0 100%

Semisub

Tenders

N/A N/AN/A N/A 4 3 1 75%

Total

Source: In? eldRigs 13 Aug 2016

This data focuses on the marketed rig ? eet and excludes assets that are under construction, retired, destroyed, deemed non-competitive or cold stacked.

oedigital.com September 2016 | OE 19 017_OE0916_Field of View_jl1.indd 19 8/23/16 6:30 PM