By Steve Gelsi
NEW YORK (MarketWatch) -- Shares of petroluem producers and refiners fell, but natural gas producers and oil service firms rose Friday, following a mixed jobs report, which said U.S. unemployment unexpectedly dropped to 9.7% in January. The NYSE Arca Oil Index (XOI 991.27, -9.93, -0.99%) dipped 0.2% to 999. The NYSE Arca Natural Gas Index (XNG 512.48, -3.03, -0.59%) rose 0.3% to 517. The Philadelphia Oil Service Index (OSX 190.13, -0.98, -0.51%) advanced 0.6% to 192.
