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* Australia's new gas fields could use shared infrastructure
* Woodside wants to build quickly as looks to start newfield
* Chevron wants to spend more time planning infrastructuresystem
* Gas has become one of Australia's biggest exports
By Sonali Paul
MELBOURNE, June 15 (Reuters) - After spending a decade andbillions of dollars developing Australia's vast gas reserves,U.S. energy giant Chevron Corp and local firm Woodside Petroleumare at odds over the pace and timing of the next leg ofexpansion.
Shipments of liquefied natural gas (LNG) have become one ofAustralia's biggest exports and a key source of revenue for manyenergy majors, so any hurdles in the sector's development couldstrike a substantial blow.
The issue comes down to how quickly to build a sharedinfrastructure system that would include a major trunk pipelinefor transporting gas from mammoth new offshore fields owned byvarious companies in northwest Australia.
Woodside wants to take the lead in such a project,pushing to build soon so it can go ahead with its $11 billionScarborough development, the only new gas field in the regionthat is primed for a final investment decision by 2020.
But Chevron would prefer to spend more time planningand building such a system, which it says could be led by it orother companies.
"I don't think there are any showstoppers in changing ... toa more shared infrastructure model," Chevron's Asia Pacificexploration and production president, Stephen Green, said in agroup interview.
"It's just getting the alignment of all the differentparties that want to participate in that value chain and comingup with the structure that satisfies each party's needs."
Firms with stakes in the region's gas fields, includingRoyal Dutch Shell, BP and BHP Billiton, will need to decide which option to pursuewithin the next 18 months to ensure untapped reserves areavailable ahead of a supply shortfall that some industryanalysts see emerging from around 2022.
Putting pressure on his peers, Woodside Chief ExecutivePeter Coleman said last month that any rival would need tonegotiate with him by September to get their gas into aninfrastructure system led by Woodside.
"They really need to get to us in the third quarter and bevery serious about what they're doing, because that window willclose," he said at an investor briefing.
Chevron has not put a cost estimate on its infrastructureplan, saying it depends on how big any trunkline is and how manyfields it connects to. Woodside has not given an exact estimateof costs for a shared project that it would lead.
"Talk of collaboration is good rhetoric, but there are anawful lot of moving parts," said Wood Mackenzie analyst SaulKavonic.
BHP and BP declined to comment. Shell declined to commentexcept to reiterate that its Australian head, Zoe Yujnovich, hascalled for "greater cooperation between ventures to reduce wasteand duplication".
Chevron and Woodside are key in Australia's LNG sector asthey operate the four LNG plants in Western Australia, andbetween them have a total of more than 60 trillion cubic feet(Tcf) of undeveloped gas resources in the region's offshoreCarnarvon and Browse basins.
BURNT BY COSTS
Until now, all 10 of Australia's LNG developments have beenbuilt as megaprojects, with the owners constructing pipelinesand LNG plants dedicated to their own fields. Critics say thathas wasted huge amounts of money as infrastructure has beenduplicated, helping push total development costs to aneye-watering $200 billion.
Burnt by a cost of $54 billion in developing its huge Gorgonproject off Australia's northwest coast, Chevron wants to changestrategy.
"It's our view that that's not the most cost efficient ...way to see resources developed across a large, prolific basinlike the Carnarvon," said Chevron's Green.
Cost control is key in a competitive industry in whichAustralia and Qatar vie for position as the world's biggestproducers and in which major new output is seen coming online inplaces such as the United States, Canada, East Africa andSoutheast Asia.
After years of sky-high LNG prices prior to 2014, when Asianspot cargoes sold for $20 per million British thermal units(mmBtu), prices are languishing at half of that.
And the fate of the biggest undeveloped gas resource offWestern Australia, the Browse project, where Woodside isoperator, will likely remain in limbo until a commoninfrastructure is built.
But both Coleman and Green expect each other's companies tocome around eventually.
"I absolutely am confident we'll work things out," Greensaid, noting that Chevron and Woodside have long been partnersin energy projects.
And the possibility of Chevron or Woodside buying outadditional stakes in the region's gas fields and LNG projectscould help align interests better to speed up a resolution.
"M&A can play a key role in helping to create alignmentacross the joint ventures," said Wood Mackenzie's Kavonic.
(Reporting by Sonali Paul; Editing by Henning Gloystein andJoseph Radford)
