You should first look at Penn State eCareer
Cabot Oil & Gas
CONSOL Energy
Chesapeake Energy
Seneca Resources
Dominion
EQT
Eclipse Resources
Rex Energy
Chevron
Range Resources
Schlumberger
Halliburton
Baker Hughes
GE Oil & Gas
Newfield Exploration
XTO Energy
Noble Energy
Shell
BP
ConocoPhillips
Nine Energy
Rice Energy
Southwestern Energy
NiSource
Williams
MarkWest
Weatherford
Keane Group
Stingray
Hilcorp
KCF Technologies
Antero Resources
Anadarko Petroleum
Hess Corporation
Concho Resources
EOG Resources
BHP Billiton
Statoil
Apache Corporation
Encana Corporation
Continental Resources
Devon Energy
Gulfport Energy
Hunt Oil
Kinder Morgan
Magellan Midstream Partners
CONE Midstream Partners
Marathon Petroleum Corporation
Occidental Petroleum Corporation
Pioneer Natural Resources
Blue Racer Midstream
Suncor Energy
Energy Transfer Partners
Repsol USA
Valero Energy
Saudi Aramco
Cameron (owned by Schlumberger)
Diamond Offshore
Seventy Seven Energy
NRG Energy