LEGISLATION allowing for the seamless transition of tenure over the Torosa, Kronos and Poseidon fields off the north west coast of Western Australia has passed the WA State Parliament.

Work done by Geoscience Australia earlier this year identified a number of new outcrops – on the Seringapatam and North and South Scott reefs – as islands, and as such part of WA.

This change to classification had a flow on effect for the extension of WA territorial waters over the fields, which form part of the Woodside-Browse joint venture and a component of ConocoPhillips’ Greater Poseidon field.

Mines and petroleum minister Bill Marmion said the state’s share of the Browse basin gas field had lifted significantly, bringing with them the promise of increased petroleum royalties for the state when the gas fields are developed.

“It is estimated the boundary changes could mean increases in state royalty collections of up to $2.9 billion over the life of the Torosa field alone,” he said.

“It is too early to speculate on the royalty potential of the Kronos and Poseidon fields but it could be significant.”

The legislation, which was passed with the approval of the Labor Party and the Greens, provided a framework to allow for the owners of the land in question to retain that ownership as the authority passed from the Commonwealth to the WA government.

As such, it will create two new state exploration permits over the Seringapatam Reef, currently covered by Commonwealth exploration permits WA 315 P and WA 398 P – both part of the ConocoPhillips joint venture.

These permits will come into being when the current exploration permits over the reef end in August 2015 and October 2016 respectively.

The legislation will also extend in area the state retention leases TR 5 and R2 to cover the area vacated by the shrinking Commonwealth retention lease WA 30 R on the Scott Reef – with the changes to occur on 23 December.

In his address to the WA Parliament, Mr Marmion said the bill helped to minimise sovereign risk by creating like-for-like equivalent state titles where parts of commonwealth titles had previously existed.

“The approach taken in the bill is for stand-alone legislation due to the unique circumstances of the state petroleum titles in the Scott Reef and Seringapatam Reef areas,” he said.

The new islands had their beginnings in 2004 when Cyclone Fay caused significant changes to the reefs. The existing laws over state waters mean that the state would retain claim to the seabed area, even if the islands were to disappear at a later date.