The Role of the 'Value for Money' Assessment Process in the Curtis Island, Australia, Multiple 2.1 Km HDD Project

摘要

The Curtis Island Water and Sewerage Infrastructure Project includes the construction of potable water and sewerrnpressure mains between the Gladstone mainland and Curtis Island, Queensland, Australia to support proponentsrndeveloping liquefied natural gas (LNG) export facilities on Curtis Island. Completed within a compressed timescale,rnthe project includes the use of value driven processes and innovative solutions and approaches along with a numberrnfirsts for trenchless Technology in Australia.rnA simple process was used to establish a common view of project drivers and define what constituted ‘value forrnmoney’ in the decision making process. This provided a collective vision for major technical decisions andrninformed the approach to technical, risk management, contracting and fee arrangement decision making processes.rnThe project represents a number of milestone achievements for HDD technology in Australia:rn1.The crossing length of 2150m and 74m deep beneath Gladstone Harbour is one of the longest of its type inrnAustralia, requiring the use of steel enveloper pipes to reduce the risk of overstressing the HDPE productrnpipe during installation.rn2.Harbour crossings were completed using two of the largest HDD drilling rigs (500 Ton) available inrnAustralia.rn3.The risk of drilling fluid losses into the sensitive Harbour environment was minimised by the contractorsrnchoice of intersect drilling (drilling from both sides and meeting in the middle) – the first successful use ofrnthis approach in Australia.rn4.An Optical Gyroscope was used for the first time in Australia to undertake the complex down hole steeringrnoperation, completed 60m below the harbor bed level.rnThe first pilot hole was completed in December 2011 followed by the installation of 2 no DN 250 PN25 HDPErnpipes in May 2012 providing interim construction infrastructure for water and sewerage. Following the successfulrninstallation of the last steel enveloper, the DN 500 PN25 HDPE water pipe was finally pulled through in Februaryrn2013, and fully commissioned in June 2013.