BUZZ-Petrofac: worst one-day drop ever on profit guidance

** Petrofac suffers its biggest single-day drop onrecord & hit lowest since 2010 after forecasting 2015 profitswell below market consensus

** Heavy trading in the stock sees volumes hitting afull-day's average in just 20 minutes

** Company sees 2015 net profit to be around $500 mln vsconsensus estimates of $688.1 mln. Second profit warnings issuedthis year.

** Lower oil prices darkens outlook at IES unit, change inproject timings & settlement related to its project in Shetland,Scotland

** One trader at a large U.S. brokerage says lower oilprices should have been in analysts' prices but operational &execution issues raised are new & will drive de-rating

** Heavily underperforms peers though weakness seen sectorwide, with Amec Foster Wheeler down 2.8 pct, John WoodGroup off 2.2 pct, Subsea 7 1.8 pct weaker

** Going into profit warning no analyst covering the stockhad a "sell" rating. 12 analysts had a "buy" rating while 8others had a sell on stock, according to StarMine (RM: tricia.wright1.thomsonreuters.com@reuters.net; RM:esha.vaish.thomsonreuters.com@reuters.net)