Whirlwind waters no worries for widening Woodside

With an existing pipeline network that covers hundreds of kilometres of terrain both onshore and offshore, Woodside’s interest in WA’s pipelines rivals many of the largest. Woodside has predicted that its existing 875 km network of subsea pipeline infrastructure will expand to more than 2,800 km in coming years if successful final investment decisions are taken on the company’s projects.

Woodside is responsible for a significant proportion of the subsea and pipelines infrastructure installed offshore WA. Cyclonic weather systems in the area mean that achieving safe and reliable operation of transmission pipelines off the North West Shelf (NWS) is often in challenging conditions for pipeline stability.

The company is well-versed in a range of secondary stabilisation methods that protect the company’s pipelines in this challenging environment. Solutions range from pre-and post-pipelay dredging and trenching to gravity anchors and rock bolts, and buckle initiators have been successfully employed to prevent lateral bending in smaller diameter pipelines.

The Woodside-operated NWS Project, which, according to Woodside “remains Australia’s largest operating resources development after 27 years of production”, uses an extensive network of pipeline infrastructure to connect its offshore facilities and to transmit hydrocarbon fluid to onshore processing facilities.

This network includes a 135 km, 1,016 mm diameter carbon steel pipeline, which in 1982 connected the North Rankin A Platform to the Karratha Gas Plant (KGP). In 1994, the North Rankin A Platform was this time connected to the Goodwyn A Platform 23 km away by a 762 mm diameter interfield pipeline.

In 2004, first gas flowed through a second 135 km long, 1,067 mm diameter pipeline – the North Rankin A Second Trunkline – connecting the KGP to the North Rankin A Platform. This was achieved by executing a hot tap tee tie-in to the live North Rankin to Goodwyn interfield pipeline.

In 2008, the central hub of the North Rankin A Platform was connected by a 49 km, 762 mm diameter export pipeline which began transporting hydrocarbons from the unmanned Angel platform back through North Rankin A and on to KGP for processing. In 2010, 24 km of 254 mm and 406 mm diameter flowlines were installed to connect the Perseus subsea wells back to the Goodwyn A Platform.

Woodside’s Pluto LNG Project, which is set to begin production in 2012, will bring gas from the Pluto and Xena fields onshore through a 180 km long, 914 mm diameter trunkline. This is connected via a riser platform to additional subsea infrastructure including two 27 km insulated carbon steel flowlines. A monoethylene glycol delivery system will operate through a 152 mm diameter pipeline, piggybacked to the main export trunkline and a 102 mm diameter pipeline running between the Pluto A Platform and the subsea wells.

Subsea and pipelines infrastructure for the Pluto project was completed in 2010, and successfully pressurised in April 2011.

Woodside has said that its proposed Browse LNG Development will transport gas and liquids from deepwater facilities to a central processing facility 70 km away, before bringing hydrocarbons onshore through a 315 km, 1,067 mm diameter export pipeline and a 508 mm diameter liquid pipeline. This project will incorporate the first steel catenary risers installed in the Australasia region.

In December 2011, the project reached a stumbling block, with the WA Supreme Court ruling that the land acquisition process for the project at James Price Point was invalid, due to an omitted detail in three of the WA Government’s notices of intention to take the land. Since this announcement, Northern Territory Chief Minister Paul Henderson voiced the possibility of Darwin becoming an alternative location for Woodside’s LNG hub.

Wheatstone clears milestones

Construction has now begun, following a final investment decision reached late last year by Chevron Australia, on the $29 billion Chevron-operated Wheatstone LNG Project at Ashburton North, 12 km west of Onslow on the Pilbara Coast in WA.

The discovery of Wheatstone in August 2004 led to Chevron’s announcement four years later in March 2008, of its intention to develop the gas resource as a greenfield onshore LNG and domestic gas project.

The foundation phase of the Wheatstone project consists of two LNG processing trains with a combined capacity of 8.9 MMt/a and associated offshore infrastructure including the processing platform, subsea equipment, drilling and a 200 km export trunkline.

Gas, condensate and associated aquifer water will be brought to the earth’s surface via a series of subsea wells and then transported through a network of subsea pipelines to a central processing platform. First gas export is planned for 2016.

The Wheatstone onshore foundation project is a joint venture between the Australian subsidiaries of Chevron (operator 73.6 per cent), Apache (13 per cent), Kuwait Foreign Petroleum Exploration Company (7 per cent) and Shell (6.4 per cent). ShawCor’s pipe-coating division Bredero Shaw, has been awarded a contract from Chevron Australia to provide pipeline coatings and related products and services for the flowlines on the project.

Successful appraisal programs, completed to further understand the Wheatstone and Iago fields’ potential, were followed by Chevron’s welcoming of environmental approval of the Wheatstone Project by the WA Minister for the Environment Bill Marmion, as well as by the Federal Minister for the Environment Tony Burke.

The Federal and WA governments undertook a co-ordinated environmental assessment. Under this process, a single Draft Environmental Impact Statement/Environmental Review and Management Program document that satisfies the requirements of each jurisdiction was required.

Gas will be processed at an onshore facility located at Ashburton North. Chevron has said that there are few suitable port sites in the region and the Wheatstone plant provides a foundation for commercialising both existing and future gas resources. The company also said that Ashburton North provides an ideal location given its proximity to the western Carnarvon Basin.

Chevron has signed a sales and purchase agreement (SPA) with Tokyo Electric Power Company to buy 3.1 MMt/a of LNG from the Wheatstone Project for a period of up to 20 years. More recently, Chevron signed a SPA with Kyushu Electric Power Company to deliver 0.8 MMt/a of LNG for up to 20 years.

The project is scheduled to start production in 2016.

BHP’s Macedon gas field

The Macedon gas field is located in the Exmouth Sub-basin, approximately 100 km west of Onslow and 40 km north of Exmouth, WA. Recoverable reserves for the Macedon gas field are between 400 and 750 Bcf of gas.

Gas from the subsea field will be piped via a 500 mm diameter, 75 km offshore pipeline and 15.5 km onshore pipeline to a gas plant at Ashburton North. The 67 km Macedon tie-in will connect the gas plant to the Dampier to Bunbury Natural Gas Pipeline (DBNGP).

The plant is anticipated to produce 200 MMcf/d of gas. BHP Billiton as operator has a 71 per cent interest in the field and ExxonMobil has a 29 per cent interest. First gas is expected in 2013.

Devilish weather for Devil Creek

Apache Energy’s Devil Creek Development Project (DCDP), a greenfield gas development located approximately 80 km northwest of Dampier Port off the northwestern coast of WA, comprises an offshore gas production platform, an onshore and offshore gas supply pipeline, a gas processing plant and gas export pipeline tied into the DBNGP.

The DCDP was initiated to recover and process the gas reserves from the Reindeer gas field located approximately 90 km northwest of the Dampier Port at water depths of 60 m.

This included the transportation and installation of an unmanned wellhead platform, together with a single 91 km, 406 mm diameter raw gas pipeline linking the offshore wellhead platform to the onshore gas plant. SapuraAcergy constructed the offshore pipeline.

Despite the worst cyclonic weather seen in two centuries, the DCDP offshore construction phase was successfully completed and handed over to Apache Energy on 21 March 2011, following seven months of construction.

Mission not impossible for DBP Transmission

With more than 50 per cent of all energy produced in WA derived from gas, the DBNGP is a critical piece of energy infrastructure in WA, with the vital role of delivering gas and supporting businesses and homes across the state.

An investment upward of $1.7 billion, since 2004, has been put toward three expansion projects, by the owner of the DBNGP – DBP Transmission. These expansions – Stages 4, 5A and 5B – have each been completed ahead of schedule and within budget.

DBP has completed the last significant works within the scope of the Stage 5B expansion project, being the Fortescue River crossing at the northern part of the DBNGP, upstream of Compressor Station 1.

DBP said that the project had the challenge of sourcing workers from across Australia. The safety of employees and the DBNGP was paramount and was the basis of judging project performance. The expansion has been completed safely and met the requirements of the Stage 5B environmental vigilance as well as the ministerial requirements.

The pipeline is now over 80 per cent duplicated, with a full-haul capacity of 845 TJ/d. Moreover, according to DBP, the additional capacity has further enhanced the overall integrity of the system.

Another substantial operational project begun by DBP in 2011 was the completion of the Pipeline Internal Inspection Project, which encompasses all pipelines owned and operated by DBP. The project was necessarily separated into four phases:

1. Pigging of the existing mainline from Dampier facilities to Kwinana Junction; 2. Pigging of all the loops installed as part of Stage 4, Stage 5A and Stage 5B expansions; 3. Pigging of all piggable laterals; and, 4. Pigging of non-piggable sections of pipeline.

At the time of writing, progress on phase one of the pigging project stood at 100 per cent complete, while phase two was at 99 per cent completion. Pigging will continue to see out phases three and four of the project in the future.

To date, DBP has completed 78 pigging runs for a total of over 9,500 km covered.

Looking towards the future, DBP said “a number of factors are crucial to ensure investment in infrastructure in public/private partnership projects that are regulated at an appropriate level”.

Gas giant APA Group’s stake

APA Group’s stake in WA includes the ownership and operation of three pipelines and a gas storage facility:

• The Goldfields Gas Pipeline (GGP), which runs from Yarraloola to Kalgoorlie;
• The Parmelia Gas Pipeline (PGP), running from Dongara to Pinjarra;
• The Midwest Pipeline (MWP) from Eradu to Windimurra; and,
• The Mondarra Gas Storage Facility.

The GGP transports gas from the Carnarvon Basin and NWS producers to mining customers in the Pilbara, Murchison, and Goldfields mining regions of WA for industrial use and power generation.

Constructed in 1996, the 1,377 km mainline is a covered pipeline and assets include maintenance bases at Karratha, Newman, Leinster and Kalgoorlie. Four compressor stations have been installed to boost the capacity of the GGP.

The GGP was expanded by 20 per cent in 2009 with the installation of two new compressor stations at Ned’s Creek and Wyloo West. Gas for the pipeline is sourced from the Carnarvon Basin and the NWS via the DBNGP.

In the south of the state, the 416 km PGP transports gas via the DBNGP to industrial markets in the wider Perth area. The Parmelia gas business includes the Mondarra Gas Storage Facility near Dongara. Gas is sourced from Perth Basin gas fields at Dongara, the Carnarvon Basin via the DBNGP, and the Mondarra storage facility.

The Mondarra Gas Storage Facility near Dongara is adjacent to two pipelines servicing Perth and the southwest of WA, including APA’s PGP. Wholly owned by APA, the Mondarra Gas Storage Facility is currently the only commercial underground gas storage facility in WA. In response to peak gas demand, APA has expanded this facility.

APA has entered into a long-term foundation contract with Verve Energy, WA’s government-owned electricity generator, for a substantial part of the increased capacity of the Mondarra facility. APA is continuing to engage with other potential customers for further services to meet growing demand for gas storage.

Other WA APA assets include the 50 per cent APA-owned, 353 km MWP, which transports gas from the DBNGP near Geraldton to power generators for mining processes in the Windimurra and Mt Magnet region; and, the 476 km Telfer Gas Pipeline, through APA’s divestment vehicle Energy Infrastructure Investments.

The large amount of activity in this region with regards to both upgrades to existing infrastructure and proposals for new infrastructure is evidence that pipelines will have a long and exciting future in WA.