Extending from the Pilbara region in Western Australia, the 1,596 kilometre Dampier to Bunbury Natural Gas Pipeline (DBNGP) supplies natural gas to industrial, commercial and residential customers in Perth and major regional centres along the pipeline route.

Since its original construction, the capacity of the DBNGP has been expanded via a number of compression and looping projects.

Currently, pipeline owner DBP Transmission is undertaking the Stage 5B Expansion project, which involves the addition of more than 110 terajoules per day (TJ/d) of firm full haul capacity and additional part haul capacity. The expansion involves the construction of 440 km of 26 inch diameter looping pipeline, the installation of an additional compressor unit and modifications at all ten compressor stations as well as some valve and meter stations.

Looping progress

Stage 5B consists of eleven separate loops, from Loop 0 near Karratha, to Loop 10 east of Bunbury. McConnell Dowell began constructing the expansion project earlier this year.

The mobilisation of personnel to site began in October 2008 and the project commenced construction in January 2009.

Construction began with Loop 10, located near Perth. Loop 9, which traverses the Swan Valley and includes both residential and vineyard areas, was the next to be constructed. Both of these loops have now been commissioned, and work at Loop 0 is nearing completion.

Work has now commenced on all loops, with physical location of the existing pipeline ('potholing') being completed for the entire route. The major construction effort is moving south into Loops 1, 2, 3 and 4, with advance works already underway on Loop 5.

“The looping project is progressing satisfactorily despite some challenges caused by weather in both the northern and southern areas. DBP is confident that the looping will be completed on time in the first quarter of 2010,” said DBP General Manager Commercial Mark Cooper.

Facilities progress

In addition to the 440 km of looping, Stage 5B involves the installation of a new compressor unit at Compressor Station 10 and equipment modifications and upgrades at all ten compressor stations.

Civil works have been completed at most sites, with mechanical, electric and installation construction in progress. All work is on schedule and major equipment items have either been delivered or are in the final stages of manufacture in line with the project schedule.

Construction challenges

DBP has said that the looping sections 0 through 8 are in remote locations from Karratha to Gingin, and involve working from remote base camps. The logistics of continually moving campsites and personnel presents one of the greatest challenges on the project. Other challenges include extreme weather conditions, geological challenges and an emphasis on zero environmental losses of both flora and fauna.

Construction of the loops has required close liaison with all stakeholders, including landowners, affected residents, government agencies, local councils and shires, local indigenous communities and other affected parties.

Mr Cooper said “DBP and its contractors maintain open communication with all of the parties impacted by our construction projects. We try to get to know the communities we are working with, and let them get to know us. This allows issues to be resolved on the ground before they become problems.”

Conclusion

Construction is continuing on schedule for the Stage 5B looping project to be completed by April 2010.

When Stage 5B is complete the DBNGP system will be 94 per cent duplicated between Dampier and Perth and 80 per cent duplicated overall.

“The DBNGP is one of Western Australia’s most critical pieces of infrastructure. Its duplication not only provides additional energy to support economic growth in the state, but also adds to the security and reliability of gas as a key input for the state’s economy,” said Mr Cooper.