IFP spearheading R&D on deepwater flow assurance, corrosion, composites

Institut Francais du Petrole is best known to the offshore sector for its work in geo-sciences, reservoir modeling, drilling, and riser analysis. All these programs are driven from the group's headquarters in Rueil, west of Paris.

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Institut Francais du Petrole is best known to the offshore sector for its work in geo-sciences, reservoir modeling, drilling, and riser analysis. All these programs are driven from the group's headquarters in Rueil, west of Paris.

IFP's other main facility, CEDI-Rene Navarre, based in Solaize, south of Lyon, is more typically associated with the Rhones-Alpes region petrochemical industry.

In fact, an important part of the Drilling & Production Technology Business Unit activity is carried out at Industrial Research and Development Center (CEDI) in England.

The main offshore expertise is in deepwater flow assurance, multiphase production, and materials engineering for hostile environments. The spacious site features some of the world's most advanced test loops, which can handle all types of reservoir fluids and gases under a wide range of pressures and flow conditions. They can also be configured to simulate production behavior at all stages of a field's life.

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Multiphase flow test loop at Solaize.
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According to Philippe Maurel, research engineer for the applied mechanics division, a large part of CEDI's offshore studies are for companies based outside France. Clients include Chev-ronTexaco and ConocoPhillips in the US, and Statoil and Norsk Hydro in Norway. "We have also worked with Petrobras and BP in particular on hydrates formation and wax deposition."

Since its creation in 1967, CEDI's stated objective has been to pursue industrial development of new techniques and technologies via three basic steps:

  • Feasibility – designing and building prototypes, then operating them under conditions close to those of a real industrial setting
  • Reliability – ensuring through tests that the new process can operate over long periods, in spite of sudden interruptions, without suffering irrevocable damage
  • Scale-up to the actual industrial setting, i.e., downhole or subsea.

To these ends, IFP employs a team of specialists in all relevant disciplines, including chemical engineering, numerical simulation, chemical kinetics, organic chemistry, materials, and mechanical engineering. The two departments most involved in offshore R&D are the Mechanics section, affiliated to the Applied Mechanics Research division, and the Materials section, part of Applied Chemistry and Physical Chemistry Research division.

Test loop portfolio

Large scale facilities operated in Solaize include two multiphase equipment test pipe loops (U740 and U756), one test loop (U767 – Lyre) for flow assurance studies (hydrates and wax formation), and one test loop (U794 – Maestro) to study the hydrodynamics of the multiphase production and advanced control of multiphase flow in hilly terrain.

The U740 test loop performs hydraulic testing of full-scale equipment such as pumps, turbines, and flow meters, in multiphase flows of oil, water, gas, or nitrogen. Pre-arranged flow rates for liquids are 0-18,000 b/d and 0-255 Mcf/d for gas, at pressures ranging from 1 bar to 50 bar and ambient temperatures.

The U756 loop provides mechanical, corrosion, and abrasion endurance testing of equipment in multiphase crudes mixed with CO2, H2S, and sand particles. Liquid flow rates here are 0-13,000 b/d with 0-170 Mcf/d for gas, at pressures ranging from 1 bar to 36 bar and ambient temperatures.

"IFP has been at the forefront of multiphase R&D since the 1980s," Maurel says. "Our first objective was to develop new technology for pumping in multiphase conditions, which led to the Poseidon project jointly carried out by IFP, Total, and Statoil. Some of our test facilities in Solaize were used to reproduce actual field conditions as closely as possible. The next step was a subsea version, Nautilus, in partnership with TotalFinaElf, Sulzer, and Alstom, Jeumont Industries (for the electrical engineering). IFP is now active in developing a multiphase turbine in collaboration with Textron-Guinard. A full-scale industrial prototype of multiphase turbine will be tested on the U740 multiphase flow-loop in 2003."

The Lyre loop is 140 m long and 2-in. in diameter. Typically, it is used for studies of gas hydrate formation and transportation, wax deposition, and flow shut-down/re-start. It can be heat-traced from 0-50° C and run under pressures up to 100 bar. It is instrumented to measure pressure drop, temperatures, and flow rates with vortex and mass flow meters.

The Lyre loop can also be adapted to simulate a variety of conditions such as single-phase, stratified, or slug flow. Within this loop, there are two specific sections. One, 22 m long, representing a low point, descends gradually to a level of -1.1 m, before ascending to its original horizontal level. There is also a 7-m long sub-cooled wax deposition section.

These facilities, built between the 1980s and early 1990s, were substantial investments. Where possible, tests are conducted using IFP-developed software, such as transient multiphase flow simulation tools (TINA, Tacite). The aim is to improve fluid component description for reservoir analysis, thereby helping to optimize design of the transportation system, for example, to avoid blockages and consequent production losses.

In its early days, the Lyre loop was primarily used for testing and validating new generation of additives for flow assurance, such as anti-agglomerants and kinetic inhibitors developed in house by IFP.

"Concerning hydrates, more and more companies are coming to IFP to help them with their studies," Maurel says. Over the last two years, CEDI has performed extensive research on the problem of gas hydrates transport in multiphase production lines. This work was carried out within the framework of a joint industry project involving BP, Conoco, IFE, Norsk Hydro, Shell, and TotalFinaElf.

"We are also working in partnership with TotalFinaElf concerning their forthcoming developments in the deepwater offshore West Africa." The aim is to develop operating procedures to study the effects of shut-down/re-start.

IFP also collaborates on a program in Norway called Hydraflow (with Statoil and TotalFinaElf), the aim of which is to use the natural properties of oil to prevent hydrates from forming plugs. More fundamental studies have been performed on the natural ability of oil to transport hydrates. This work is in partnership with TotalFinaElf and Petrobras.

"We also adapted Lyre to rig up a special flow loop for wax deposition studies. This was done for BP, which wanted to test new additives for one of its fields in the UK North Sea. We used their existing additives in our tests, but we have since developed our own paraffin inhibitor, which is the result of a joint development between IFP, TotalFinaElf, and CECA, and now marketed by the latter under the trade name Prochinor AP757."

Wax management

"Another program concerns the development of sensors for wax detection," Maurel says. "In this regard, we are involved in a European Commission-funded project with TotalFinaElf, Metravib RDS in southern France, and KYE in the UK."

The project, called WaxMonitor, is developing a new system for wax management in pipelines during the design and operating phases. The wax detection system (WDS) comprises a series of sensors attached externally to a subsea production pipe.

These sensors detect wax thickness and deposition rate at various locations, the aim being to provide a reliable evaluation of wax deposits throughout the line to assess the efficiency of additives and pigging procedures. Metravib, which also provided instrumentation for the Girassol riser towers, is responsible for the sensors, with KYE in charge of marinization of the system.

First-phase studies have proven that the WDS does not disrupt operations during installation. Five concepts of clamp design are under review that employ conventional subsea technology for installation on pipelines or flowlines. Tests were carried out in the Lyre loop. A field test is currently being conducted on a 4-in. production pipeline in southwest France. The partners are now seeking an operator willing to install the WDS on an offshore production line prone to waxing problems.

IFP also undertakes experiments in collaboration with TotalFinaElf concerning heavy oil transportation issues. "This is a big concern in Venezuela in particular." Tests are performed on a loop using flocculated slurries or solvent solutions.

As regards the U794-Maestro loop, this is used in the Threeplex project, an IFP-led initiative that began in 2001. The consortium includes IFE and NTNU in Norway, Imperial College in London, and Sintef in Norway. Work is due to be completed this year.

"Our task is to study the complexities of subsea flow behavior, which we do using our TINA (Tacite) and Olga simulation softwares," Senior Research Engineer Daniel Ferré says.

The tests have involved a three-phase mix of gas, water, and oil. "We put in very low flow rates for all the fluids in the loop, in order to simulate production of wells approaching the end of their productive lives. At that stage, for instance, the reservoir lacks sufficient energy to push the gas into the riser. This can lead to big fluctuations in flow and pressure: This phenomenon is well known as 'severe slugging.' For a 10-km stretch of pipe, this can mean waiting hours for new flow to feed through."

Flexible pipe studies

The Materials section's test facilities at CEDI are used for analysis of the long-term behavior of polymeric and composite materials, and the corrosion resistance of metallic materials. Larger flexion benches and pits also allow tests of flowlines or other oilfield components when subjected to different types of crudes, acid gases or seawater, or under severe temperature or pressure conditions.

This department also analyzes potential use of new resins or composite materials for offshore production and oil and gas transportation.

"We work with the major service companies, and also with oil and gas operators within the framework of joint industry projects," says Senior Research Engineer Joseph Martin. Examples of recent studies include high-pressure, high-temperature tests on flexible pipe polymers, analysis of the behavior of elastomeric material used in seals under high pressure conditions, and development of new lighter weight composite lines for drilling and production.

At CEDI, IFP operates test rigs able to work with gas mixtures including CH4, CO2, and H2S. For example, these test rigs can be used to study the permeability of gases through the polymeric sheath of a flexible pipe.

"We can reach right down to the bore of the flexible," Martin says. "We also use gas chromatography to measure the composition of gases entering and leaving the sheath, in test conditions up to 130° C, 300 bar." The results are used to assess the life of flexible pipes under dynamic stress/corrosion conditions.

Another test pit, operating in conditions up to 1,100 bar and 200° C, has been used for analysis of polymers employed in kill and choke flexible lines. "We have also done tests on elastomers used in O-ring seals for drilling purposes, in our 200° C/850 bar cell. Additionally, we have three test cells made of Hastelloy, used to qualify polymers and composite materials, but also cements, which can work in extreme conditions with mixtures of oil, brine, methane, and acid gases such as CO2 and H2S, up to 300 bar / 200° C. These devices can perform very long-term experiments. For example, they have been used to select and qualify an IFP-formulated epoxy resin developed for the PatchFlex products marketed by Drillflex, a Schlumberger subsidiary."

The Materials department also develops and tests new materials such as new types of coatings to prevent corrosion of pipes at temperatures of up to 140° C (thermoplastic/thermoset blends).

"We are also working a lot on new types of insulation materials, such as syntactic foams. It's a big challenge to ensure that these foams can sustain the variabilities of temperature and pressure encountered in water depths of 3,000 m. Pursuant to a Clarom project conducted with Ifremer, Bouygues Offshore, Stolt Offshore, and TFE, IFP proposes today a new JIP project (named Tideep), to test and qualify syntactic foams for ultra-deep thermal insulation."

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