** Oilfield services co's shares down 2.8 pct at563.5 pence after co reported H1 results
** Co reported 7.4 pct fall in H1 EBITA and 19.3 pct fall inrev, hurt by slump in global oil and gas markets
** Stock trading at 5-month lows, with nearly 15 pct of itsdaily avg volume traded in the first half hour
** Stock biggest drag on the STOXX Europe 600 oil and gas and the FTSE 350 oil equipment and services indexes
** Shares rose as much as 2 pct on open, but quicklyreversed course
** Traders said the stock rose on the increased div, new5-yr contract with Shell but reversed as weakness in crude oilprices continues to outweigh company fundamentals
** U.S. oil prices fell to their lowest in more than sixyears on Tuesday (abhiram.nandakumar.thomsonreuters.com@reuters.net)