Subsea welding goes deeper
A decade of research at the UK's Cranfield University has confirmed that subsea welding can be successfully conducted at depths of up to 940m, more than 600m deeper than previous records and far deeper than the 180m depth limit for divers. The research, initially funded by the Engineering & Physical Sciences Research Council, used a dry hyperbaric welding chamber installed at the university in 1997 that simulates water depths of up to 2500m.
Test results demonstrated that welding at greater depths was possible, and in 2004, industry partner Statoil began performing pre-qualification and qualification studies to determine the practicality of achieving the same results in the field.
This year, the first successful deepsea trials were conducted off Norway. ‘It is excellent that the field trials demonstrated the practicality of using hyperbaric MIG welding for deepwater remote applications,' said Neil Woodward of Isotek Oil & Gas, who has been working at Cranfield on behalf of Statoil on the qualification work.
The university is conducting further research focused on improving weld quality and process reliability.
Cool certificate
SBM Offshore's Cryogenic Offshore Offloading and Loading (COOL) LNG system received a certificate of design assessment from ABS and a certificate of fitness for service from DNV, making it the industry's first fully qualified and certified offshore LNG transfer hose system. The COOL system comprises a flexible cryogenic floating LNG hose and connectors designed to allow the transfer of LNG between vessels in a tandem moored configuration. The system can be used to offload LNG from a floating LNG production vessel to an LNG carrier, or to import LNG onto a floating LNG storage and re-gasification unit.
The tandem offloading configuration allows LNG cargoes to be moved to offtake carriers in harshersea conditions than current methods. SBM began developing a cryogenic transfer system to address the challenge in 2005. The COOL hose combines an outer marine hose with an inner composite LNG hose; the space between the hoses is filledwith insulating materials that have ‘excellent properties over the full range of ambient to cryogenic temperatures,' SBM said. The system's connector, a cryogenic quick-connect/ disconnect system joining the COOL hose to the LNG carrier bow manifold, includes botha structural connector and a fluid connector, the latter developed in partnership with FMC Technologies.
Looping the LOOP
France's Alstom Grid has been awarded a contract from the Louisiana Offshore Oil Port, or LOOP, to deliver a new supervisory control and data acquisition (SCADA) system for LOOP's entire pipeline system, including its offshore platforms, pumping and storage facilities, and refinery distribution pipelines. The project will be built on Alstom Grid's e-terrahabitat software platform and will incorporate a suite of liquid pipeline SCADA applications from delivery partner EvolutionSCADA. The project also includes delivery of a complete communications network to replace LOOP's existing network infrastructure witha fault tolerant local and wide area network architecture, Alstrom Grid said.
Platform power
Caterpillar has supplied CNOOC with eight 16 M 32 C crude oil engine generator sets to be installed on a pair of platforms bound for the South China Sea's Panyu 4-2/5-1 field. Each generator set will provide 7680 kWe (9600 kVA) at 750 rpm of rated power. Each platform will include four generator sets and auxiliary equipment, including fuel supply modules, cooling modules, separator skids, lube oil skids and control panels.The 16 M 32 C is a medium speed, long stroke engine featuring flexible camshaft technology, high efficiency turbochargers and a bore of 320mm. The modules are designed, built, plumbed, wired and factory tested in Rostock, Germany, simplifying the subsequent installation process at shipyards, Caterpillar said.
Rope record
Cortland recently produced the world's largest 12-strand rope for a European client, constructed on the 12-strand braiding machine using Cortland's Plasma syntheticfiber. The rope will be used to create an industrial lifting sling.
This rope was created from more than 52,000 individual Plasma strands using Cortland's 12x12 braiding technique, which combines individual 12-braided ropes into a strong and flexible 12-strand rope. The finished size is 176mm with a minimum tensile strength of 1845t.
The rope is almost eight times lighter than a comparable steel rope would be, Cortland stated. The rope will be used in a grommet configuration with an MBL exceeding 3044t for heavy lift operations.
Subsea skimmer
As the oil industry works to address concerns about drilling in the Gulf of Mexico, a German manufacturer of subsea oil and gas pumps is offering a new approach to cleaning up spills before they reach the surface.
Bornemann Pumps is developing a subsea vacuum cleaner – a subsea skimmer – that could be deployed over leaking oil and gas at depths of up to 10,000ft. The company believes such technology could have minimized the impact of last year's Macondo spill in the Gulf of Mexico by removing hydrocarbons from the water while experts gathered the resources to cap the well.
‘There has to be a backup plan in case an accident like this happens again,' said Axel Jaeschke, head of subsea research for the company, which recently opened offices along Houston's Energy Corridor.
Bornemann's concept for a subsea skimmer rests heavily on the company's experience in manufacturing twin screw pumps for boosting mixtures of oil, gas and water. The skimmer would use a collection cone atop a twin screw booster pump and motor. Alternatively one or more skimmer pump modules could be integrated into a containment system to control cleaning performance and the liquid level inside the collecting dome.
Jaeschke said the twin screw pumps can handle additional the hydrates slurry, caused when hydrocarbons mix with cold seawater. These hydrates created a particular challenge for BP as it tried to bring the Macondo well under control.
Bornemann studies show the hydrate formation can be avoided by heating or injecting different inhibitors. Some recirculation and turbulence in the skimmer-pump inlet can also prevent the hydrates from agglomerating, keeping them in slurry form. Accurate controls inside the dome can also help to minimize the amount of hydrates.
Bornemann said its pump and cone could be suspended from a surface vessel and kept in position by a preinstalled system sited at the leak. ROVs would help to install and position the subsea skimmer and supervise the quality of the cleaning process.
Route survey
UTEC Survey's GAVIA AUV wrapped up the system acceptance test of a sub-bottom profiler module for the AUV. With the addition of the adapted Teledyne Benthos Chirp III system, UTEC says the enhanced GAVIA AUV now provides a comprehensive, pre-engineering survey capability particularly suited to subsea pipeline, umbilical and cable route surveys.
The GAVIA AUV's design allows the end-user to attach an individual sensor package or a combination of packages, including multi-beam, side-scan or sub-bottom profiler. These sensors, combined with a state-of-the-art inertial navigation module, provide an accurate, efficient and stable work platform that delivers unmatched data quality, says UTEC.
‘The ability to provide a full pre-engineering route survey capability from a modular, easily transportable AUV system demonstrates UTEC's commitment to providing a truly global geophysical service, in shallow to medium water depths, deployable from any suitable costeffective vessel of opportunity,' said UTEC's director of sales and marketing Trevor Hughes.
Tight spot
A large multinational oil and gas producer encountered a challenging flow measurement application on a 24in gas export line coming off an offshore platform in Southeast Asia. While the initial plan was to install an ultrasonic flow meter, this plan was re-evaluated after learning of the high CO2 content of the gas.
The installation was tight due to existing equipment, with no room for the typical straight-pipe run required by many flow meters. The high CO2 levels were a concern because this frequently causes problems for ultrasonic meters due to the attenuation of ultrasonic signals being extremely high in CO2 compared to other gases.
In looking for an alternative solution, the engineers contacted McCrometer to review the V-Cone Flow Meter. The V-Cone relies on advanced differential pressure measurement technology, which isn't affected by CO2 or other specific gases. It is also particularly useful in tight-fit conditions such as this application, which was in close proximity to a T-elbow, McCrometer said. After reviewing third party tests done in accordance with API22.2, which proved that the V-Cone needs little upstream and downstream piping, the engineers decided on a V-Cone, which can handle high CO2 content and provide high accuracy in tight spaces.
The V-Cone's self-conditioning flow technology design reduces straight pipe run requirements up to 70%. Its stable flow profile provides accuracy to ±0.5% of actual flow and repeatability to ±0.1% over the entire range. It is available for 0.5in to 120in lines, with a 10:1 turndown ratio. With no moving parts, maintenance is virtually unnecessary and a long life provides a low cost of ownership, according to McCrometer.
CARBON COLLABORATION: Magma Global and Victrex Polymer Solutions are collaborating on new solutions for deepwater transfer of subsea oil & gas. Magma specializes in developing risers, jumpers, spools and flowlines. Magma's high-performance carbon polymer pipes are based on the VICTR EX PEEK polymer. The pipes are said to offer improved reliability, increased performance, lighter weight and longer life than conventional unbonded flexible pipe or steel solutions. Victrex technical program manager Geoff Small (pictured on right) said the company is working closely ‘with the engineers at Magma to develop and produce a VICTR EX PEEK product exclusively for Magma's application.' Douglas-Westwood estimates subsea pipelines will account for over 50% of the $139 billion capex spend on subsea hardware over the next five years, or $13.9 billion/year over the period. ‘We believe with the development of our carbon polymer pipes we can deliver risers and flowlines that can offer significant performance improvements over incumbent technologies in all key areas, especially weight, fatigue and long-term reliability,' said Martin Jones, CEO at Magma Global.
FINE FILTER: Daewoo Shipbuilding & Marine Engineering has awarded VWS Westgarth a contract to design, supply and deliver an ultrafiltration system and a sulphate removal package (SRP ) for the FPSO destined for Total's CLOV development offshore Angola. VWS anticipates completing the project in January 2012. The ultrafiltration and SRP will be installed on the FPSO topsides to provide the necessary seawater treatment for subsea well injection. The ultrafiltration unit, which is the pre-treatment step to the SRP , will have a capacity of 391,288b/d of water and the sulphate removal package will treat 374,230b/d of water. The fine filtered seawater (nominally 0.01μm) from the ultrafiltration system provides the feed for the SRP . Ultrafiltration provides a significant weight/footprint reduction and improved water quality compared with multi-media seawater filtration technology. The SRP removes sulphates and other divalent ions from injection water to enhance oil recovery using Dow Filmtec membranes. The removal of these ions reduces the tendency of barium sulphate and strontium sulphate scale to form in the reservoir, and enhances oil recovery.
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