Abraxas Petroleum Corporation [AXAS]
Allied Resources, Inc. [ALOD]
Altex Industries, Inc. [ALTX]
Anadarko Petroleum Corporation [APC]
Apache Corporation [APA]
Apco Oil and Gas International Inc. [APAGF]
Aspen Exploration Corporation
ATP Oil & Gas Corporation [ATPGQ]

Barnwell Industries, Inc. [BRN]
Bayou City Exploration, Inc. [BYCX]
Baytex Energy Corp. [BTE]
Berry Petroleum Company [BRY]
Blue Dolphin Energy Company [BDCO]
BMB Munai, Inc.
Bonanza Creek Energy, Inc. [BCEI]

Cabot Oil & Gas Corporation [COG]
Callon Petroleum Company [CPE]
CAMAC Energy Inc. [CAK]
Canadian Natural Resources Limited [CNQ]
Carrizo Oil & Gas, Inc. [CRZO]
Chesapeake Energy Corporation [CHK]
Cimarex Energy Co. [XEC]
Clayton Williams Energy, Inc. [CWEI]
CNOOC Limited [CEO]
Cobalt International Energy, L.P. [CIE]
Comstock Resources, Inc. [CRK]
Contango Oil & Gas Company [MCF]
Continental Energy Corporation [CPPXF]
Continental Resources, Inc. [CLR]
CREDO Petroleum Corporation
Crimson Exploration, Inc. [CXPO]
Crosstex Energy, L.P. [XTEX]

Delek Logistics Partners, LP [DKL]
Denbury Resources Inc. [DNR]
Devon Energy Corporation [DVN]
Diamondback Energy, Inc. [FANG]
Double Eagle Petroleum Co. [DBLE]

Earth Search Sciences, Inc. [ESSE]
Emerald Oil, Inc. [EOX]
Enbridge Energy Management, L.L.C. [EEQ]
Endeavour International Corporation [END]
Enduro Royalty Trust [NDRO]
Energen Corporation [EGN]
Enterprise Products Partners L.P. [EPD]
EOG Resources, Inc. [EOG]
EPL Oil & Gas, Inc. [EPL]
Equal Energy Ltd. [EQU]
ERHC Energy Inc. [ERHEE]
Evolution Petroleum Corporation [EPM]
EXCO Resources, Inc. [XCO]

Far East Energy Corporation [FEEC]
FEC Resources, Inc. [FECOF]
FieldPoint Petroleum Corporation [FPP]
Forest Oil Corporation [FST]

Gasco Energy, Inc.
Gastar Exploration Ltd. [GST]
Genie Energy Ltd. [GNE]
GeoGlobal Resources Inc. [GGR]
GMX Resources Inc. [GMXRQ]
Goodrich Petroleum Corporation [GDP]
Gran Tierra Energy Inc. [GTE]
Gulfport Energy Corporation [GPOR]

Harvest Natural Resources, Inc. [HNR]
HKN, Inc. [HKN]
Houston American Energy Corp. [HUSA]

Isramco, Inc. [ISRL]

Kosmos Energy Ltd. [KOS]

Laredo Petroleum Holdings, Inc. [LPI]
Linn Energy, LLC [LINE]
LinnCo, LLC [LNCO]
Lone Pine Resources Inc. [LPR]
LRR Energy, L.P. [LRE]
Lucas Energy, Inc. [LEI]

Magellan Petroleum Corporation [MPET]
Matador Resources Company [MTDR]
McMoRan Exploration Co. [MMR]
Memorial Production Partners LP [MEMP]
Mexco Energy Corporation [MXC]
Mid-Con Energy Partners, LP [MCEP]
Midstates Petroleum Company, Inc. [MPO]
Miller Petroleum, Inc. [MILL]

National Fuel Gas Company [NFG]
New Concept Energy, Inc. [GBR]
Newfield Exploration Company [NFX]
Noble Energy, Inc. [NBL]

Oakridge Energy, Inc. [OAKR]
Oasis Petroleum LLC [OAS]

Panhandle Oil and Gas Inc. [PHX]
PDC Energy, Inc.
Penn Virginia Corporation [PVA]
Permian Basin Royalty Trust [PBT]
PetroQuest Energy, Inc. [PQ]
Pioneer Natural Resources Company [PXD]
Plains Exploration & Production Company [PXP]
PrimeEnergy Corporation [PNRG]
Pyramid Oil Company [PDO]

QR Energy, LP [QRE]
Quicksilver Resources Inc. [KWK]

Range Resources Corporation [RRC]
Rosetta Resources Inc. [ROSE]
Royale Energy, Inc. [ROYL]

San Juan Basin Royalty Trust [SJT]
Sanchez Energy Corporation [SN]
Saratoga Resources, Inc. [SARA]
SM Energy Company [SM]
Southwestern Energy Company [SWN]
Spindletop Oil & Gas Co. [SPND]
Stone Energy Corporation [SGY]
Suncor Energy Inc. [SU]
Swift Energy Company [SFY]

Talisman Energy Inc. [TLM]
Tengasco, Inc. [TGC]
Texas Vanguard Oil Company [TVOC]
The Reserve Petroleum Company [RSRV]
TransGlobe Energy Corporation [TGA]
Triangle Petroleum Corporation [TPLM]

U.S. Energy Corp. [USEG]
Ultra Petroleum Corp. [UPL]

VAALCO Energy, Inc. [EGY]

Warren Resources, Inc. [WRES]