Roxar Garners Patent for Retrievable Canister

Roxar subsea Multiphase meter's subsea r
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Roxar said that its subsea multiphase meter's subsea retrievable canister, which houses the meter's electronics and flow computing modules, has been awarded a U.S. patent (No. 7,181,980, February 2007).

The patent, which relates to a multiphase meter "directly attached to, but detachable from, a separately retrievable canister containing a multiphase flow meter detector," follows extensive qualification testing with ExxonMobil, with the first two meters installed in ExxonMobil's Kizomba B field, offshore Angola, in 2004.

The benefits to the E&P operator of the subsea retrievable canister, which contains electronics, the CPU (Central Processing Unit) and power, include low and cost effective maintenance with limited subsea intervention requirements, high flow measurement availability, 100% redundancy on all electronics, and easy installation and simplified subsea structure design. The canister can be retrieved through a standard remotely operated underwater vehicle (ROV).

Roxar CEO, Sandy Esslemont, said:

"Today's patent is a tribute to the design philosophy behind the Roxar subsea Multiphase meter – keep it simple and limit the equipment that needs to be installed subsea; make sure that that any components that fail do not impact production; and commit to a flexible and lightweight design that can be incorporated with existing subsea modules.

"The result is that, whereas some of our competitor products can be subject to costly subsea interventions – both in terms of money (replacing a subsea valve can cost up to $100,000, for example) and lost production, the Roxar subsea Multiphase meter and its retrievable canister offer outstanding measurement availability, robustness and low maintenance requirements."

Today, over 80 Roxar subsea Multiphase meters of this design have been ordered worldwide with, as well as ExxonMobil, customers including Total, which is installing the meters in the Rosa oil field, and Cameron, which is installing the meters in the deepwater Akpo field, offshore Nigeria.

The subsea Multiphase meter provides accurate and continuous on-line monitoring of the flow rates of oil, water and gas in subsea well streams, using a combination of density and electrical impedance measurements to determine the phase fractions. The meter helps operators determine the optimal production capacity of each well (thereby avoiding the risk of overproducing the well), increase flow assurance from the fields and optimize the production process.

Through a standard remotely operated underwater vehicle to retrieve the canister, installation and maintenance of the meter can take place with no impact on production, without the need for subsea intervention, such as dedicated test lines and manifolds, and without the need for full body replacement, should electronics fail. The meter is close to being neutrally buoyant in water.

The meter is more accurate than separation-based systems because it is independent of separation efficiency and insensitive to slugs, foam, carry-overs and emulsions and because it provides measurements continuously in real-time. The Roxar Multiphase meter uses a Dual Velocity™ method for the handling of phase slip, not requiring mixers to homogenize the flow, or separators to split the flow before measurement and also offers 100% redundancy on two different velocity measurements (venturi and X-corr).

Roxar is a leading international technology solutions provider to the upstream oil and gas industry. The company creates value for its customers through innovative products and services that help achieve maximum performance from oil and gas reservoirs.

With its head offices in Stavanger, Norway, Roxar employs over 650 staff across a network of wholly owned offices in Europe, the Americas, Africa, CIS, Asia Pacific and the Middle East. Founded in May 1999, the company generated revenues of approximately US$160 million in 2006. Roxar's International customer base includes all of the multinationals, major independents and the majority of national oil companies.

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