Archives for posts with tag: pipelines

The North Sea is home to a dispersed mass of steel and concrete, namely: 509 active fixed platforms with a combined weight exceeding 8 million tonnes; 1,440 subsea structures; 9,370 active wells and their completions; and over 45,000km of pipeline. Under the provisions of the OSPAR Convention, field operators will be obliged to decommission and clean all this up one day. And that day is approaching.

Diamonds And Rust

Decommissioning entails plugging wells, removing platform jackets, topsides and subsea structures, and, ultimately, complete site remediation. Oil companies in the North Sea are now having to contemplate this process at fields as recoverable reserves approach depletion. Since first oil in 1967, approximately 54.1bn bbls of oil have been produced in the area. However, production in 2015 is forecast to stand at just 2.86m bpd, compared to the 2000 peak of 5.9m bpd. The value of offshore field infrastructure consists in its ability to assist in the extraction of oil and gas; for the 47% of fixed platform tonnage installed on North Sea fields that began production more than 25 years ago, the point at which this is no longer the case is getting closer. But only 88 platforms in the area have been decommissioned so far, and for good reason.

Worth Fighting For

Decommissioning can be money and time-intensive. The decommissioning of the Brent facilities is expected to take ten years. Even small projects are expected to take two years and more than $300m in CAPEX. Hence, operators are trying to stave off decommissioning through enhanced oil recovery (EOR) to extend field life, or by tying new field developments to existing structures. For example, while the 12 wells on Heimdal are being abandoned, the platforms are being kept to process gas from Vale and other fields.

However, it is thought that in the current oil price environment, OPEX is encroaching on profits at a rising number of fields. Operators striving for fiscal discipline are between the hammer and the anvil: either run fields at a loss, or shut fields down and book the decommissioning costs.

Pain And Pleasure

This choice might be painful for oil companies but there is potential upside for many vessel owners. Drilling rigs and well intervention vessels will be needed to plug many of the wells. Crane vessels, self-elevating platforms and heavy lift vessels will be needed to remove and transport topsides and jackets (indeed, part of the rationale of the “Pioneering Spirit” is that it is one of very few units capable of lifting massive structures like the 42,500t topsides of the “Gullfaks A” gravity base platform). MSVs, DSVs and ROV Support vessels can be used to assist throughout decommissioning and will be especially important for removing subsea structures and for site remediation, when dredgers will also have a part to play. These various vessels will need to be assisted throughout the process by OSVs and utility support vessels.

Oil companies active in the North Sea might prefer not to charter all these vessels just to exit dead fields. But sooner or later (quite possibly sooner) they will have little choice. This could potentially benefit many different owners, with decommissioning becoming an important driver of North Sea vessel demand.

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The rigid pipe layer fleet is complex, varied and sometimes perplexing: S-lay, J-lay, reel-lay; barge, vessel, semi-sub; tensioners, carousels, moonpools – units therein defy easy comparison with one another. And so, unlike in many sectors of the offshore fleet, it is not immediately clear what is a ‘high-spec’ and what a ‘low-spec’ unit. What is needed, then, is a framework to analyse the 172-strong pipe layer fleet…

Offshore Operations

In essence, pipe layers are used to install rigid pipelines on the seabed, primarily during the development of offshore fields. These pipelines are used to export oil/gas to shore, or to transport fluids between seabed or surface installations within a project area. Pipe laying is conducted during the EPC phase of project development, consequent on award of (typically lump-sum) EPIC and SURF contracts, usually to specialist offshore construction companies like Allseas, McDermott, Saipem, Subsea7 or Technip, who own 4, 5, 14, 6 and 6 pipe layers respectively – 20% of the fleet. There is no pipe layer spot market as such, so comparing day rates to pick out the high-spec from low-spec units is not possible.

Inscrutable Idiosyncrasy?

Vessels’ traits are not immediately helpful either. Monohull structures account for 19% of units and barge/semi-sub structures for 81%. Pipe sections are welded on-board and deployed via J-Lay towers (8% of units) or S-Lay stingers (76%), the letter indicating the curvature of the pipeline as it is lowered to the sea floor. However, 3% of vessels have both J-Lay and S-Lay structures; 16% use cranes or have hybrid, reel-lay systems; and the tensioner capacities of lay systems (i.e. the weight of pipeline they can support) range from under 10mT up to 2,000mT. There is no simple correlation between a single feature and a unit’s capabilities: “Lorelay” has tensioners of 265mT, yet cannot lay pipes in ultra-deepwaters; “C Master”, with tensioners of 160mT, can. The secondary functions of units can also vary greatly: 10% of units have ROV capabilities, for example. Moreover, 19% of units in the flexi-lay fleet can install rigid pipelines (and 5% vice versa). How then, amidst this variation, to distinguish a ‘high-spec’ from a ‘low-spec’ pipe layer?

A Promising Perspective

One way is to cross reference the maximum pipe lay water depth of units with the maximum diameter of pipe they can lay. Thus the 12 units in the “red” segment of the inset chart (e.g. “Seven Borealis” and “Sapura 3000”) could be considered high-spec and versatile, competing with units in the “dark blue” segment for ultra-deepwater subsea contracts, but with the “light blue” segment for large export pipelines in shallower waters. In the opposite quarter of the matrix, the 55 “grey” units are mostly barges, deployed in shallow waters like the Niger Delta and Lake Maracaibo. One could say there are four (overlapping) markets for pipe layer work. The range of EPC contracts for which construction companies are likely to bid will depend in part on the segmentation of their pipe layer fleets.

So, pipe layers have an array of characteristics complicating segmentation. However, some units are clearly better suited to some projects than others. By cross-referencing factors like water depth with pipe width, one can craft a framework for sorting through this diverse fleet.

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