Annealing of large-bore welded stainless steel pipe at Sosta’s manufacturing plant. Photo courtesy of Sosta

In early November 2007, Sosta’s pipe manufacturing plant in Könnern, Germany is preparing to tie up close to one quarter of its annual capacity to supply welded duplex stainless steel flow-line pipes for Petroleum Development Oman (PDO).

The project will facilitate evacuation of a mixture of wet gas and condensate at the rate of 1.5 to 4 million cubic meters per day from the Burhan West field to the existing Saih Nihayda Gas treatment facility for further processing and treatment. The 36-kilometer-long pipeline will pass through desert and wadis. Challenges for the project lie in implementation from concept to commissioning in the shortest possible time frame − less than 24 months. Duplex stainless steel was selected as the piping material due to presence of carbon dioxide in the wet-gas/condensate stream, and also to availability of material given the tight time frame.

“This is a high-profile project both for PDO and for us,” says Edwin Saathof,  Director of Sosta, a company specializing in austenitic, duplex and nickel-alloy welded pipes for oil & gas projects worldwide, including LNG plants, terminals and flow lines. Prior to the Burhan West project, Sosta has manufactured altogether 300 kilometers of duplex pipes for different oil & gas companies worldwide.

The current contract, which requires pipes of 8 and 14 inches in outer diameter, is well in line with Sosta’s specialization. “Our strengths are in capabilities and know-how to manufacture large-diameter pipes, a sole focus on project deliveries, and ability to produce from both coil and plate,” Mr. Saathof says.

To meet the high corrosion resistance and strength requirements, PDO pipe specifications prescribe the highly alloyed duplex stainless steel grade 2205 and a wall thickness from 5.2mm to 8.7mm. According to Mr. Saathof, the overall specifications are the most stringent applied to flow-line pipes.

The duplex contract went to Outokumpu, based on a number of factors. First, Outokumpu is one of the leading producers of duplex stainless steel, both in coil and plate. Second, Mr. Saathof commends Outokumpu’s level of technical assistance and product quality, pointing out, “Partnering with Outokumpu gives a great deal of assurance to our customers.” Moreover, Outokumpu has been a steady partner to Sosta during the pipemaker’s crucial years of growth. Mr. Saathof comments on the partnership, “Sosta has quadrupled production output over the past four years. Outokumpu has supported our growth, being very reliable in terms of delivery times to keep our production running smoothly when we have been working our mill at limit.”

Sosta will be manufacturing and delivering the Burhan West flow-line pipes by mid-2008.

Project facts

Project
Welded duplex stainless steel flow-line pipes for the Burhan West natural gas field in Oman developed by Petroleum Development Oman

Pipe manufacturer
Sosta GmbH of Germany, a subsidiary of Arcus Holding B.V. of the Netherlands

Sosta’s scope of supply
Pipe dimensions: 
Outer diameter 8″ (total of 10km) and 14″ (total of 33km)
Wall thickness 5.2mm to 8.7mm

Outokumpu supply
3,055 tons of duplex stainless steel coil
Duplex grade: 2205 (UNS S31803, EN 1.4462)

For more information, contact:
Nicole Friedrich
Regional Sales Manager
Outokumpu Sales Office in Willich, Germany
Tel. +49 2154 4960
E-mail: nicole.friedrich(at)outokumpu.com