After going it alone for so long, BG Group may have to take a lower price for a stake in its Queensland Gas Company's $US15 billion ($13.2 billion) coal seam gas project at Gladstone, analysts say.

BG owns an unusually high 93.75 per cent of equity in the two-train Queensland Curtis liquefied natural gas (LNG) project and on Tuesday was reportedly seeking investors to take a stake of up to 20 per cent, with price expectations of $US1.5 billion to $US2 billion.

Analysts said this price - about $US100 million for each per cent of equity - was in line with the $US1.1 billion that Sinopec paid for 10 per cent of Origin Energy's Australia Pacific LNG project in January.

Advertisement: Story continues below But one analyst, speaking off the record, said prices were falling, even though buyers were getting partially developed projects, from a peak in 2008 when BG bought QGC for $5.3 billion and Petronas paid $US2.5 billion to buy 40 per cent of the Gladstone LNG project.

Recent equity deals on Queensland CSG projects have been done at about 80￠-100￠ a gigajoule of proved and probable reserves, whereas earlier deals such as Santos-Petronas and AGL Energy's purchase of Sydney Gas were at prices about $3.75-$4.25 a gigajoule.

The China National Offshore Oil Corporation (CNOOC) owns 5 per cent of QCLNG and Tokyo Gas owns 1.25 per cent. Both were seen as potential buyers yesterday.

A senior manager for Tokyo Gas said: ''Generally speaking, we decide to take a stake in a project which we expect a decent return from. This is a project in which we've made such a decision, so I can say we're interested, depending on conditions if and when negotiations begin''.

BG said last month it would sell $US5 billion of assets over two years, to maintain commitments including at the Santos Basin oil field off Brazil.

CLSA Asia Pacific analyst Mark Samter said BG did not have gas reserves to supply a two-train project and would need to buy third-party gas or new upstream assets.

LNG customers such as Tokyo Gas were natural buyers of QCLNG, but Mr Samter said: ''You can't rule out any of the majors, either.''

QCLNG is the most advanced of the three approved projects and due to start shipments in 2014. BG has agreed to sell LNG to China, Japan, Singapore and Chile and to provide gas to markets in eastern Australia.