Novel Tri/SWATH design for oil industry

Harsh environmental conditions make the complex tasks associated with oil recovery and well maintenance from certain oilfields in the North Sea extremely challenging, often resulting in oil recovery rates 20% below what should be expected. This is a problem which is being addressed by an advanced maritime vessel design being developed by QinetiQ and OTG.

The UK-based QinetiQ is working with Norwegian exploration and production technology company, OTG (Oilfield Technology Group AS), to develop a new type of vessel which will allow oil companies to conduct sophisticated operations in a stable environment while weathering some of the world?s stormiest seas.

The agreement between the two companies follows a two-year joint development programme and the establishment of OTG Interventions AS, a wholly owned subsidiary of OTG, which will build and own the vessel. OTG Interventions AS is currently evaluating several ship operators and will soon announce who will be selected to operate the unique Tri/SWATH vessel in the Norwegian sector of the North Sea.

The initials Small Waterplane Area Twin Hull (SWATH) vessel normally consists of two parallel torpedo like hulls attached to which are two or more streamlined struts, which pierce the water surface and support an above water platform. The advantage of such a design is that they are more stable, less prone to pitching and rolling and requiring less power for propulsion than conventional designs.

QinetiQ’s unique approach to SWATH design is to develop vessels with a tri hull configuration which provides even greater stability, a vitally important feature for vessels commanding complex work in often very stormy seas.

Currently, oil companies have 15 ? 20% lower oil recovery rates from subsea wells compared to platform wells in the North Sea and other offshore basins. This is because there is currently no cost effective solution to performing subsea repair and maintenance on the growing number of subsea wells. The Tri/SWATH vessel should allow this work to be performed at one fifth the cost of traditional approaches such as (anchored) semi-submersible vessels, and less than half of the cost of dynamically positioned semi-submersibles.

OTG Interventions AS and QinetiQ expect to complete the final stages of vessel design later on this year for operation in mid 2007. QinetiQ’s role will be to assist in achieving type approval from the necessary classification societies and to support the owner to ensure the vessel is built to the required design specifications.

The two companies have also started to evaluate this concept for other oil and gas applications, including an ultra optimised drilling vessel that can operate at a lower day rate than conventional drillships and drilling rigs. Chris Ross, QinetiQ’s Chief Naval Architect described the agreement as “lighting the touchpaper” for a potentially “very exciting” next stage development for QinetiQ’s maritime design capability. “The Tri/SWATH RLWI (Riserless Light Well Intervention) vessel is a novel approach to solving a high value need for the oil & gas industry. For QinetiQ, the prestige and showcase opportunities for us in the design of such complex ships are enormous,” said Ross.