Remote modules
25 April 2008
Sakhalin is a Russian island off the eastern coast of mainland Russia north of the Japanese island of Hokkaido. The island, which is 948 km by between 27 and 160 km, has offshore fields believed to contain some of the world's largest oil and natural gas reserves – 14 billion barrels (2.2 km3) of oil and 96 trillion cubic feet (2,700 km3) of gas.
Two international consortia, Sakhalin-1 and Sakhalin-2, have been formed to develop the resources. Sakhalin-1, operated by Exxon Neftegas Ltd, is projected to produce some 2.3 billion barrels of oil and 17.1 trillion cubic feet of gas from three fields, including the Chayvo field, the first to be developed. The Chayvo development includes the construction of the onshore processing facility (OPF) to produce up to 250,000 barrels of oil and 270 million cubic feet of gas per day by late 2006.
Both road and weather conditions on Sakhalin are extreme. Infrastructure to facilitate the construction of the OPF hardly exists, while freezing temperatures and heavy snowfall only allows working between early June and early November. It was decided to modularise the OPF, build it in 39 modules in Korea and to ship it by barge to Chayvo on the east coast of Sakhalin over a period of two years.
To allow the modules to be discharged a temporary port facility was built. To reach the construction site, some 12 km inland, a temporary heavy haul road (HHR) had to be built through a complicated and environmentally fragile ecosystem including marshland and permafrost. The HHR includes an 800 m long bridge with a 9 m wide road surface that is limited to 15 tonne axle loads. It leaves only 150 mm clearance on both sides for the largest modules to pass.
The local transport and installation of the modules on Sakhalin was awarded to international specialist Mammoet. The Dutch company set up a temporary and winter proof camp for its 60 strong international crew. Included is a 22 x 60 m workshop and climate controlled storage facility for the new 356 axle lines of Scheuerle self propelled modular transporter (SPMT).
In 2005 the Mammoet crew moved and installed the first series of 26 modules ranging in weight from 700 to 1,800 tonnes.
Following the winter break work has resumed. In time for this, the first of 13 modules, ranging in weight from 1,300 to 1,800 tonnes and measuring up to 84 m long and more than 20 m wide, arrived by barge. The modules were rolled off on a double width arrangement of 44 axle lines of SPMT. Limitations on the bridge mean the heaviest and largest modules have to be moved on a three-wide 58 axle line arrangement of SPMT (total 174 axle lines).
The three wide trailer is set-up to a width of 8.23 m, allowing, in this case, less than 400 mm clearance between the guard rail and the SPMT each side. Limited space for final installation requires many of the modules to be temporarily stored again on site before final installation can be carried out using, most of the time, a three wide 36 axle line SPMT configuration. Mammoet's crews work shifts around the clock to finish the module handling from arrival by barge to final installation on site.
