UPDATE 1-ConocoPhillips to sell stakes in Australian gas assets to PetroChina
* PetroChina to acquire 20 pct of Poseidon gas field in the Browse Basin
* Companies to jointly study shale formation in China's Sichuan Basin
* PetroChina to also buy 29 pct of onshore Goldwyer shale in the Canning Basin
Feb 20 (Reuters) - ConocoPhillips said it will sell some of its stake in two Western Australia exploration assets to Asia's largest oil producer PetroChina Company Ltd.
PetroChina will acquire 20 percent of Poseidon gas field in the Browse Basin offshore Western Australia and 29 percent of onshore shale formation Goldwyer in the Canning Basin in the same region.
According to Conoco's website, the company owns 60 percent of some exploration permits in the Browse Basin. Karoon Gas Australia Ltd holds the remaining interests.
The deal comes two months after PetroChina agreed to buy BHP Billiton's stake in the Woodside Petroleum-led Browse LNG project, estimated to cost $30 billion to build.
State-owned Petrochina has set aside $16 billion for overseas investment in 2013.
China's state-owned energy giants have been bidding aggressively for foreign oil and gas fields as Beijing looks to secure energy supplies to meet rising demand.
The country aims to double the share of gas in its overall energy mix to more than 8 percent by 2015.
Under Wednesday's deal, ConocoPhillips and PetroChina will also study the potential for unconventional resource development in the 500,000 acre Neijiang-Dazu Shale formation in the Sichuan Basin in southwestern China.
Financial details of the deal were not disclosed.
Shares of Houston-based Conoco were down 1 percent at $57.97 on the New York Stock Exchange on Wednesday.