(Updates with no immediate comment from Santos, background on...

(Updates with no immediate comment from Santos, background on Santos)

SYDNEY, Nov 16 (Reuters) - A consortium of global energy investors has approached Australian oil and gas major Santos Ltd (STO) with a proposal for an all-cash takeover worth A$11 billion ($8.34 billion), media reported on Thursday.

The Australian Financial Review reported Linda Cook, a former executive director of Royal Dutch Shell , had recently approached the Santos board with an invitation to support a scheme takeover.

Indicative pricing for the bid was expected to be around A$5.30 per share, a 21 percent premium to Wednesday's closing price of A$4.38. The pitch was expected to be ready to present to Santos within weeks, the AFR said without citing sources.

Santos did not immediately respond to a request for comment. The company earlier this month said it expects to hold its gas output roughly steady over the next several years, with growth to kick off in 2023 from projects in northern Australia and Papua New Guinea.

Chief Executive Kevin Gallagher sought to reassure investors at a briefing that the company has halted a decline in its natural gas output from its ageing Cooper Basin field and is on track to cut net debt to $2 billion by the end of 2019.

Santos expects production in 2018 to be roughly in line with this year at between 55 million and 60 million barrels of oil equivalent (mmboe).

However, the company forecast its sales - which include some third party gas - would drop by about 7 percent to between 72 and 78 mmboe in 2018, partly due to declining output from non-core fields in Indonesia and Vietnam.

At the same time it plans to increase capital spending by about 17 percent to between $825 million and $875 million.

The AFR reported that the bid vehicle was Harbour Energy, a Washington-based energy investment company that is run by Cook. Harbour was set up by resources investment house EIG Global Partners.

($1 = 1.3186 Australian dollars)