Oil and Natural Gas Corporation will award six small onshore oil fields this month to private companies for bringing them to production in the next two-three years.

The state-run exploration giant is roping in small private firms for developing the fields as it had found them too expensive for a company of its size to develop.

"We have completed the tendering process and hope to award them soon," ONGC chairman and managing director Subir Raha told reporters in New Delhi.

Of the 18 marginal fields put for bid, ONGC is awarding two fields in Gujarat to GSPC on nomination basis. Three blocks did not get any bid while three others did not get sufficient responsive bids.

"Of the remaining 10, we have decided to seek more clarifications on four gas blocks and will for now award the remaining 6 blocks to private firms," he said.