By Ryan Vlastelica
NEW YORK, Oct 10 (Reuters) - Energy shares fell on Friday, extending their recent weakness as crude oil dropped to its lowest level since 2010.
The S&P energy index fell 1.5 percent on Friday, by far the worst-performing group of the day. It has fallen for seven of the past 10 sessions, and is down 5.2 percent this week, its worst since November 2011.
With the week's decline, the sector has turned negative for 2014. It is now the year's worst-performing S&P sector.
U.S. crude futures lost 1.6 percent to $84.44, falling to their lowest since November 2012. Brent crude lost 1.1 percent and earlier dropped to its lowest since 2010 as Saudi Arabia said it increased production last month.
Oil prices are down 23 percent from a recent closing high, putting the commodity into bear-market territory amid signs of slowing global growth.
Exxon Mobil Corp fell 0.9 percent to $90.97 while Chevron Corp was down 1.4 percent to $112.90. Halliburton Co slumped 5.5 percent to $54.09 and has lost almost 13 percent this week.
The Energy Select Sector SPDR exchange-traded fund fell 2.3 percent to $82.75.
Index snapshot at 1031 EDT (1431 GMT):
* S&P 500 fell 14.79 points, or 0.77 percent.
* Nasdaq Comp fell 75.76 points, or 1.73 percent.
* Dow industrials lost 43.12 points, or 0.26 percent.
* Russell 2000 fell 12.2 points, or 1.14 percent.
* S&P MidCap lost 16.35 points, or 1.23 percent.
* S&P SmallCap lost 5.33 points, or 0.86 percent. (Editing by Bernadette Baum)