Aussie Potential Being Tapped

Geological Variety

If you’re looking to get in on some big-time E&P action, head “down under” to Western Australia -- it’s a rockin’ scene these days.

Besides the potential to tap into some major hydrocarbon deposits, you’ll find a welcoming environment.

According to the Western Australia Department of Industry and Resources (DoIR), the state ranks high in international surveys as a destination for exploration ventures. Low sovereign risk and the fiscal and legislative regime along with noted successes in offshore exploration are credited with making the locale attractive as an exploration target. Petroleum prospectivity has been demonstrated both onshore and offshore.

The state is the major oil and gas producer in Australia from the Bonaparte, Canning, Carnarvon and Perth basins, with 2004 reserves pegged at 135 gigalitres of oil, 282 gigalitres of condensate and 3,408 cubic gigametres of gas, according to DoIR. (A gigalitre equals one million kilolitres.)

The state boasts 66 producing oil and gas fields containing over 80 percent of Australia’s natural gas resources. It leads the nation in gas and LNG production.

Western Australia’s E&P activity goes back a number of years -- in fact, it has been producing crude oil since 1967, and the first commercial quantities of natural gas went on production in 1971.

Basin Breakdown

If you decide this is the place for you to strike the big one, bone up real good on the geology in your area of interest.

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If you’re looking to get in on some big-time E&P action, head “down under” to Western Australia -- it’s a rockin’ scene these days.

Besides the potential to tap into some major hydrocarbon deposits, you’ll find a welcoming environment.

According to the Western Australia Department of Industry and Resources (DoIR), the state ranks high in international surveys as a destination for exploration ventures. Low sovereign risk and the fiscal and legislative regime along with noted successes in offshore exploration are credited with making the locale attractive as an exploration target. Petroleum prospectivity has been demonstrated both onshore and offshore.

The state is the major oil and gas producer in Australia from the Bonaparte, Canning, Carnarvon and Perth basins, with 2004 reserves pegged at 135 gigalitres of oil, 282 gigalitres of condensate and 3,408 cubic gigametres of gas, according to DoIR. (A gigalitre equals one million kilolitres.)

The state boasts 66 producing oil and gas fields containing over 80 percent of Australia’s natural gas resources. It leads the nation in gas and LNG production.

Western Australia’s E&P activity goes back a number of years -- in fact, it has been producing crude oil since 1967, and the first commercial quantities of natural gas went on production in 1971.

Basin Breakdown

If you decide this is the place for you to strike the big one, bone up real good on the geology in your area of interest.

The DoIR emphasized the vastness and variety of the geology in Western Australia challenges explorationists to apply new technologies when searching for hydrocarbons in a basically under-explored land.

“The oldest rocks on earth are found in Western Australia,” said Peter Baillie, chief geologist Asia Pacific at TGS-NOPEC, who will co-chair both a poster session and one of the oral sessions on the petroleum prospectivity of Western Australia at the upcoming AAPG international meeting in Perth.

“We have basins from the Archean to those currently forming,” he said.

Of interest to the petroleum industry are the sedimentary basins with prospectivity from the Proterozoic through to the present, Baillie noted.

“There’s a series of older basins that dropped within Gondwanaland and extend from Pre-Cambrian to Permo-Triassic age,” he said, “and there’s a younger set of basins related to the breakup of Gondwanaland. These are the basins that formed on what we call the North West Shelf, which is the northwest margin of the Australian continent where the major hydrocarbons are found.”

There’s some serious E&P action on the Shelf, particularly in the Carnarvon Basin, which is mainly offshore. This is one of Western Australia’s five major basins, which also include the Perth, Canning, Browse and Bonaparte basins, according to DoIR.

DoIR noted the primary focus of petroleum exploration and development has been, and continues to be, the Northern Carnarvon Basin, where a range of production facilities already are in place. The basin is one of the more intensely explored areas of Australia.

The Northern Carnarvon Basin is the locale of the giant multi-field Greater Gorgon complex, which is currently being explored and developed. Baillie described Gorgon as “a major, major resource” of perhaps up to 5 percent of the world’s natural gas supply.

He made the verbal observation that about half of Perth is employed there in one way or another.

“In the Gorgon Field complex, which is in water depths of 700 to 800 meters-plus, there’s reservoirs that range in age from Triassic to Lower Cretaceous,” Baillie noted. “The source is also variable and is either Triassic or Jurassic.

“In Western Australia, the normal thing is to find porosity below the regional seal, which is called the Muderong and is of Cretaceous age,” he said. “Normally you go for the first porosity below that, which can be Lower Cretaceous, Jurassic or Triassic.

“Perhaps the best reservoirs are in the Triassic formation called the Mungeroo,” Baillie noted. “It’s a fluvial sandstone that can have multi-darcy porosity at four kilometers of depth.

“I call it the Mighty Mungeroo.”

LNG Potential

Industry activity in this region is not just about drilling wells.

LNG is a big deal and becoming even more so.

Chevron, for instance, is in the engineering phase for a natural gas project to be built at Gorgon, according to Bill Robinson, senior adviser Chevron Australia and oral sessions co-chair for the Perth meeting.

The $11 billion-plus LNG project appears to be surmounting the final hurdles in the approval process. Chevron is operator with a 50 percent stake, while Royal Dutch Shell and ExxonMobil each hold a 25 percent share.

Robinson noted this is a 20-40 Tcf development, and construction possibly could begin early next year. Woodside Petroleum currently operates what reportedly is Australia’s largest single LNG production facility, which is on the North West Shelf.

Besides the copious quantities of gas in this region, the Gorgon complex is unique in having a high CO2 content -- as much as 10-13 percent, according to Robinson.

“The plan is to compress and inject the CO2 near the LNG plant on Barrow Island into a static aquifer on the island,” Robinson said. “It will be the world’s largest geo-sequestration project for CO2 geo-sequestration.”