Oil and Natural Gas Corporation has blamed oil regulator V K Sibal of causing a crash in the company's shares by publicly rejecting a gas discovery contrary to upholding private sector claims in identical circumstances.

Alleging a 'bias', ONGC Chairman R S Sharma has written to Oil ministry saying Sibal's media announcement had led to ONGC's share price crash from Rs 906 on February 19 to Rs 796 on March 1.

"The resultant loss in the market cap has been of the order of Rs 23,527 crore," he wrote.

The director general of DGH had last month disallowed discovery of natural gas off the Andhra coast as ONGC had abandoned the well before doing conventional testing. 

ONGC's assessment of over 14 trillion cubic feet of inplace gas reserves was based on MDT test conducted in presence of DGH representative, it stated. 

Sibal said he wasn't aware of the complaint. "I am not aware of that. I have nothing more say."

Sharma sought an independent inquiry into Sibal's 'malicious campaign' against ONGC.

"The blatant bias against ONGC in rejecting discovery of (well) UD-1 is obvious with reference to similar discoveries on MDT test having been allowed by DGH in favour of other non-PSU operators in adjoining acreages.

"We also have serious apprehensions that different norms are being applied for relinquishment of acreages for ONGC vis-a-vis certain other non-PSU operators.

Even the quantum of penalties imposed on ONGC are highly excessive as against other operators for non completion of committed work programme," he wrote.