The Press Trust of India news agency says Oil and Natural Gas Corporation, Indian Oil Corporation and Oil India Limited made their joint, non-binding bid a few weeks back.
It cited an unnamed executive as its source.
ConocoPhillips is selling a 50 per cent stake in its Alberta oilsands assets.
India imports three-quarters of its oil and its state-owned oil companies have been looking to secure energy supplies overseas to meet rising domestic demand.
Executives at the three Indian companies could not be reached for comment.
ConocoPhillips spokeswoman Davy Kong says, "We do not comment on market rumours."