The field joint scope of work in offshore oil and gas projects by welding the 12 meters long pipes used in deepwater projects, and the coating of the union, along with the naval facilities costs involved, are important points of concern of companies assigned to such activities. Not only for financial reasons, but also for operational and environmental benefits, the architecture of the systems to supply of the pipes requires improvements in manufacturing technology.

 

 

The production of coated double joints (DJ) appears in this context as an opportunity for optimization of these projects. The manufacture of coated double joints onshore presents advantages, as shown below:

1- Reduction of the necessary welding time with assembly line fabrication;
2- Increase a better NDT control for welding joints, mainly for FSHR or other special requirements for fatigue resistance welds;
3- Improvement in welds repairs along with subsequent pipe movement when necessary without impact schedule;
4- Increase in Welding efficiency with the precision alignment of the welding pipes (Hi/Low of 1.0mm and coupling straightness of 25 mm;
5- Anticorrosive and thermal coating capacity in pipes with different geometry - collars (J-lay collars and Buckle arrestors) with the use of lateral extrusion technology;
6- Project optimization of pipeline off-shore installation with reduction of the required time and costs, mainly to afford the specialized ships; and
7- Allow for a better efficiency in environment damage control and safe production operations, preventing industrial accidents

 

 

 

The production of welds in a controlled manufacturing environment provides excellent opportunity to achieve improved logistical control and shorter schedules. Even more important for deepwater projects is the improvement in quality that can be obtained in a controlled indoor manufacturing environment where precision fit-up and mechanized and/or automated welding processes can improve impact and fatigue performance of the weld joints.

The coating of pipes with variable geometry is not used to be done offshore. Using the technology of application with lateral extrusion, these pipes coating and finishing can be done easier onshore.

The reductions of costs and delivery times are two of the main advantages in onshore coating double joints use. Instead of working on offshore field joints, welding and coating, the onshore services practice can produce cost and schedule savings up to 50%.
Socotherm (SCT) and ATS/CyberSolda (ATS) had recent experience providing 12’ OD and 18’ OD Double Joints for Acergy France and Technip Offshore. The development of the services took place from year 2005 to 2007 in Ubu Socotherm Brasil Plant, in Espirito Santo, Brazil.

ACERGY GREATER PLUTONIO DEVELOPMENT PROJECT

The Acergy Greater Plutonio Project had as the final client the BP Company and the DJs produced at Socotherm Ubu Marine Base were installed in the Angola Block 18 field in water deep of 1500meters.

 

 

 

Socotherm and ATS produced 80 km (6500 welds) of DJ pipes of 12’ OD and several wall thicknesses’, the used pipes was seamless X65 pipes fabricated in Brazil and the used J-Lay collars were F-65 fabricated in Italy. The project was carried out in two industrial facilities, ATS/CYS Welding Structure and SCT Thermal Insulation Coating Structure, both located in the same yard, sharing many industrial support as energy and water source, security and safety resources, health assistance, food facilities, pipe handling equipment, maintenance support, joint management, offices, etc... and having both installations on the same location one can avoid one large moving stage.

 

 

 

The welding services were based on GMAW/RMD and SAW welding processes. The SCT/ ATS plant facilities include a welding assembly rack that provides transverse and longitudinal movement along with a precise hydraulic alignment system. These stations can provide the pipes and J-lay collars vertical and lateral movement allowing an optimum pipe alignment for root and hot passes weld. For example, in order to fit with a special flowline section it was fabricated 9.5km of fatigue sensitive welds, using the same qualified weld procedure (GMAW-RMD – that is not common), but this time associated with a very tight dimensional sorting in order to reduce the hi-lo and obtain a perfect fit up, and in addition to this highly controlled welding monitoring process tighter acceptance criteria, was used Automatic UT.

The Thermal Insulation services were done in polypropilene (PP) and Syntactic Polypropylene coating using the well proved Socotherm Multy-Pass® Coating Process that give liveliness and velocity to the production rate guaranteeing excellent anticorrosion coating application and uniform and concentric Thermal coating application.

The coated DJ were moved to Angola, by standard general cargo ships fitted to handle long coated pipes, in three load outs from Ubu Samarco Port Facility. The movement from Socotherm Plant to port facility were made by trucks fitted with extended body platform to be suitable to 26 meters long pipes. These logistics arrangements proved to be very affordable for all players.

 

 

 

TECHNIP PDET PROFUNDO DEVELOPMENT PROJECT

Petrobras had become a major offshore producer once the Brazilian has more then 65% of the oil production carried out in deep water environment. So, the company requires high standards of technological solutions for the scope of work developped by the suppliers. Job completion in tight schedules and cost effective operations along with environmental protection and safety conditions are essentials for the work to be done. These requirements demands innovation and specific solutions from its suppliers.

 

 

 

The PDET Project (Oil Outflow and Treatment Plan, in English - Plano Diretor de Escoamento e Tratamento, in Portuguese) designed by Petrobras is a clear example of the challenges Socotherm and ATS/CyberSolda had to deal with. Technip, as the main contractor, TenarisConfab, Corus, ATS/CyberSolda and Socotherm Brasil were some of the companies involved in the PDET Profundo stage. The focus area is Campos Basin, the source of 85% of Brazilian oil production, where the PDET will produce enough oil to allow the country to consolidate its national self-supply policy, even with surplus for exportation.

The PDET will connect the Campos Basin production to the refineries located in the Brasil southeast region. To do the job a mixed transport solution was adopted combining various transport methods: oil pipelines and vessels to the São Sebastião terminal; and existing onshore oil pipelines to the refineries. The transport solution comprises five Petrobras production platforms working together as PDET Profundo system. The collection platform PRA-1, settled in shallow waters 35 km offshore, will receive production from five platforms through individual oil pipelines, P-51 Marlim Sul, P-53 Marlim Leste and P-52, P-55 and Module-4 Roncador, all located in deep waters. The oil collected by the PRA-1 will be bombing to FSO and monobuoys, where the oil vessels will pick the oil up to be carried to the terminals in Rio de Janeiro e São Paulo (São Sebastião). The oil will be distributed to the refineries through existing onshore pipelines.

 

 

The first solution minded by Petrobraswas the installation of deep water pipelines connecting PRA-1 to the five platforms using 12mts long pipes to be welded on board, as a previous step. This process would lead to high operation costs and long project terms. Overcoming this hurdle was the task requested to Socotherm Brasil, subsidiary of Socotherm Americas, member of the Italian Group Socotherm SpA, based in Adria.

The goal of the solution proposed by the company was the optimization of both the time frame and resources by carring out the assembling/welding process of 24mts long pipes “Double Joints”, instead of 12mts long “Single Joints”, in a onshore plant, avoiding the offshore job for this scope of work.
The advantages of this solution are based on:

 

• Higher efficiency on the welding process, allowed by the use of hydraulic and motor equipment in a production line - conveyor racks - that guarantees the alignment of the pipes to weld (alignment structures – Hi/Low of 1.0mm and coupling – straightness of 25mm every 24mts roughly).
• The possibility of applying anticorrosive and thermal coating on pipes with different geometry (J-Lay collars and Buckle Arrestors) with the use of Multy-Pass® side extrusion technology developped by Socotherm.

 

The PDET welding and the coating scope of work was carried out in a strategic area close to Petrobras operation zone, in the Socotherm Brasil marine base located in Ponta de Ubu, Espirito Santo state. This was a key factor in the optimization of the logistical matters. The SCT/ ATS Ubu industrial installation produced almost 215.220ft of 18’ OD coated pipeline and more than 2700 welds for the PDETProf project. It was developed with SCT and ATS, coating and welding companies, sharing the industrial support provided by a common structure.

The PDETProf welding scope of work was developed with a remarkable difference from the previous on: the root and hot pass used the GTAW welding process as required by Petrobras Company during the qualification phase of the project. The subsequent fill and cap welds used the same process as Greater Plutonio development (SAW welding processes). The welding assembly rack made easy the adjustment process as the conveyor rack were fitted to a larger OD and heavier pipe, but even with the welding process modified to another slowly, and the size and weight increases, the production showed up very higher than normal process without the movement rack pipe assembly.

The same usefulness was encountered as SCT was required to adjust the coating line to the new weight, dimension and characteristics of Corus and Confab provided 18’ OD pipes. TenarisConfab and Corus were responsible for the supply of 40km and 28km of 12m long pipes, respectively. Having the opportunity to assemble and coat Double Joints (24m long pipes), Socotherm Brasil applied a thermal coating of Wetisokote Solid Propylene on the pipes supplied. The pipes were 18in OD, X60 grade and WT ranging from 0.625in to 1.125in.

 

 

 

The Wetisokote solid propylene is obtained from an exclusive Socotherm formula, which is adjusted to the specific project needs and applied over the anticorrosive propylene protection by means of Multy-Pass® side extrusion technology. This methodology allowed a coating thickness of 2.05in on pipes 24m long.

The choice for this coating process was derived from the need to avoid the damaging effects of paraffin deposition and/or hydrates inside the pipes. This protects the oil flow from the platforms throughout the whole life of the project. Compared to other similar standard materials, this coating has a better technical performance and is even more cost effective.

The coating services had to be fitted to a specific design as the PDETProf DJs had a kind of collar welded between the single pipes, the coating plant was working with the DJs with the Acergy J-Lay Collar at one end, not in the middle, so SCT had to modify the coating process.
The delivery of the PDETProf DJs was made by Barges fitted to these DJs, the load outs carried 115 DJs per Barge, leaving Ubu Port to Rio de Janeiro, where the DJ entered in a Quad Joint facility before their sea trip, managed by the “Deep Blue” vessel, to Campos Basin.

 

 

CONCLUSION

Therefore, when analyzing the benefits of offshore installation of coated double joints, many advantages have been observed.

 

 

 

 

The simple reason on been producing the welding and coating Double Joints (DJ) in an onshore plant, and the barges have been adapted to the offshore DJ work, can benefit not just the reduction in half time the offshore work, but reducing as well the logistic costs, operational flexibility due to companies site commom service needed been shared, ease of operational management, improved quality and safety levels due to a stable environmental control and reduction of delivery schedule.

Socotherm coating technology associated with “Double Joints” operation has provided Petrobras impressive economy in terms of project time and costs, without mentioning an increment of entire pipeline coating quality. The evidence of this economy is the reduction in 50% of all “field joint” coating process.

Regarding project time costs benefits, the schedule reduction of 50% during pipe laying barge installation is a important highlight. This was due to a reduction in the number of offshore joints required; half the conventional quantity was used. Regarding quality issues, it is easy to conclude that in comparison with the standards projects, a flowline fabrication based on coated “Double Joints” presents more continuity in terms of thermal ans anticorrosion properties, since the weak points are reduced in 50%. The company has helpped Petrobras to satisfactorily complete this first project stage that is targeted to change the energetic matrix of Brazil.