The Republic of Congo (ROC) relies heavily on the oil industry: the production of about 261,000 barrels of oil per day generates approximately 40 per cent of the country’s wealth.

M’Boundi is an ROC oil field some 55 km inland from the coast that is looking to use seawater to pump into its wells to increase oil production, a practice recognised throughout the industry. To achieve this goal, a new 600 mm diameter pipeline is being constructed to bring seawater from the coast to the oil field. To ensure that the steel pipeline has a significant economic lifespan, a plastic pipe liner will be installed to protect the inner pipe wall from the rigours of operating in a saltwater environment. The installation of the plastic liner is to be carried out on the construction site using Swagelining™ techniques.

The client for this project is ENI of Milan, Italy, with the main contractor being SOCOFRAN, who will execute the main civils/excavation works for the project. Contractor Beender has been engaged to complete the pipeline fabrication and installation works.

M’Boundi project

Preparations

Preparations for construction on the M’Boundi Project, which is believed to the longest ever swagelining project undertaken, have begun with the early phases of the first pipes being laid out. Once pipeline installation starts, lengths of pipe, as delivered, are laid out along the route. These are then welded into sections, known in the oil industry as stalks, above ground.

The individual stalks are then swagelined. The pipe being used for the swagelining process is approximately 60 km of PE100 SDR 33, 610 mm diameter PE pipe manufactured and supplied by GPS PE Pipe Systems.

The final stage in the pipe preparation is to weld together the swagelined stalks into a complete length using specialist connectors. It is only at this stage that the trench for the pipe is excavated alongside the pipeline. The pipe is then lowered into the trench and buried. Welding and winching

The welding process using the special connectors is a vital part of the construction process to ensure that the steel pipe ends weld successfully and the plastic liner pipe ends are also sealed to provide a continuous protective internal liner to the pipeline.

Pipe Equipment Specialists has several years experience in large scale swagelining of this type and in order to ensure that the process is carried out to the highest possible standard the company is providing constant support onsite with the presence of a swagelining supervisor.

In addition to the basic swagelining equipment, the required time frame of the project meant that the work needed to be completed quickly and it was decided that normal winching products would have had difficulty meeting the required production schedule. Pipe Equipment Specialists investigated how this potential problem could be overcome.

Ultimately, using basic technology often found in the pipe bursting sector, the company developed a ‘continuous pull’ rod winch with the capacity to winch 35 tonnes at speeds of up to 10 metres per minute. Whereas normal rod winches are reciprocal and require the hydraulics to be reset at the end of each stroke, the new winch has a pair of pulling jaws and hydraulic cylinders which operate so that as one set is pulling the rod, the second set is resetting for the next pull stroke, allowing continuous pulling to be achieved.

It is believed that the new winch technology will enable the M’Boundi project to be completed within the required time frame. Innovation leads to successful outcome

The first shipment of equipment left the UK in March 2009, with its arrival onsite in April. The first installation operation was in May. The swagelining operations for the pipeline are scheduled to run for approximately six months.

Managing Director of Pipe Equipment Specialists Steve Kent said “The equipment order is the largest that we have ever had to fulfil and production of the necessary rigs and support equipment is running to schedule.

“Whilst this is a major production and logistical effort for us, we are very confident that we will be making our deliveries on time and on budget for this very important oil field project in the Republic of Congo. Our operatives will be available throughout the project to offer their experience and technical know-how and they will be fully supported by our UK staff for the duration of the works.”