CTour technique on course to manage two-thirds of Norway’s produced water

April 1, 2006
ProPure AS, which owns and markets the CTour produced water treatment technology, has developed a compact skid-based test system for use by potential clients.

ProPure AS, which owns and markets the CTour produced water treatment technology, has developed a compact skid-based test system for use by potential clients. The company sees a need for such a system in light of the growing interest it is experiencing for its technology as it steps up its international marketing drive.

Its contribution to produced water treatment has been acknowledged by the committee of OTC, in the form of a Spotlight on New Technology Award for innovative technologies.

The compact test system, which is under construction, weighs about four tons and has dimensions of 3.7 m x 1.6 m x 2 m. ProPure already has a test system in which the equipment is divided between three smaller skids, so Managing Director Rolf Thorkildsen is confident that the test needs of most potential clients can be met whatever the space constraints in which the equipment needs to be installed.

The growing stringency of environmental regulations is one reason why the CTour technology has attracted attention in the industry. It can achieve an oil-in-water content of 1-4 ppm, and also remove dissolved components such as benzene, toluene, ethylbenzene, and xylene (BTEX), polycyclic aromatic hydrocarbons (PAH), alkylphenols, and naphtalenes. This enables it to meet the stringent requirement for no harmful discharges to the sea, which came into effect in the Norwegian offshore sector at the beginning of this year.

CTour technology is unique in removing both dispersed and dissolved hydrocarbon components, according to Thorkildsen. Another benefit is that it can be used to treat large volumes of produced water-up to 600,000 b/d or more. This makes it suitable for use on large fields which have reached the stage of maturity in which the water cut is at a high level.

The company is aware of no other treatment method that can handle such large volumes while at the same time removing the dissolved components, Thorkildsen says. In addition, CTour can be used to treat produced water with high feed concentrations-up to 1,000 ppm of oil-in-water or more.

View of the compact, skid-based CTour test system under construction by ProPure.
Click here to enlarge image

The technology involves the injection of condensate into the produced water upstream of the hydrocyclone or cyclone phase. A high shear force is imparted to the produced water stream to homogenize it ahead of the condensate injection. This aids the coalescing effect whereby the oil droplets and the aromatic components are attracted to the condensate, forming large droplets which can be efficiently removed at the cyclone phase.

The CTour technique, which is protected by a number of patents, was invented in the mid-1990s by Inge Brun Henriksen, and is named in honor of the French scientist Cagniard de la Tour, who in 1822 first discovered the phenomenon of supercritical fluids. It was developed at Rogaland Research, the Stavanger-based research institute, before being spun off in 2003 as a commercial product in the hands of CTour Process Systems, which merged with ProPure earlier this year. Henriksen is still with the company as technical adviser.

The efficiency of the method was established by a field test carried out on Statoil’s Statfjord field in 2003. In 2004 Statoil awarded CTour Process Systems a $3.6 million contract to install its system on all three Statfjord platforms. Statoil’s choice of the method was testimony to its ability to handle large volumes of produced water, as more than 1 MMb/d of water is currently produced across the three Statfjord platforms. This was followed in 2005 by a further contract, worth $1.3 million, for the provision of the CTour technology on Statoil’s Snorre A platform.

Meanwhile, CTour Process Systems has also performed successful tests for ConocoPhillips, which together with Statoil was one of the sponsors of the development. Last year ConocoPhillips awarded it a contract to supply the technology to the Ekofisk 2/4 J and M platforms. Here its systems will treat a total volume of around 300,000 b/d of produced water, achieving an oil-in-water content of 1.5-3 ppm.

By early 2007, when all these systems are commissioned, the CTour technology will be used to treat 1.7 MMb/d of produced water, equivalent to two-thirds of all projected produced water discharges in the Norwegian sector at that time.

In the UK sector CTour has done a study for Talisman’s Claymore platform, though in this case the operator decided against produced water treatment in favor of reinjection. But CTour continues to work with Talisman on other UKCS installations.

ProPure is a fully owned subsidiary of Pure Process Solutions AS - the Pure Group - which is owned by Energivekst development fund with 51% interest, and Statoil, with 49%. Last year the group set up an associate company, ProSep, in Houston to target the Gulf of Mexico market.

In the Far East, where it has had talks with a number of potential customers, ProPure is in the process of deciding where to set up a subsidiary. It is also in contact with a number of companies in the Middle East and with Petrobras in Brazil.

The Pure group specializes in produced water, oil and gas treatment technologies. Among other developments being carried out by ProPure is a method of selective hydrogen sulfide removal from gas, under a joint industry project funded by ConocoPhillips, Statoil, and Total.