R. H. Engelke Oil & Gas Producers
Ram Energy
Ramshorn Investments Inc.
Rand Energy Co.
Randolph Enterprises LC.
Ranger Oil Ltd.
Rebel Drilling Co. LP.
Red Planet Mining LP.
Redeco Energy Inc.
Redfish Leaseholds Inc.
Redwood Energy Ltd.
Refuge Exploration Co. Inc.
Reliance Insurance
Remington Oil & Gas Corp.
Repsol YPF
Resolute Natural Resources
Resource Strategies LLC.
Rex Energy Limited Partnership
Rialto Energy Inc.
Ricks Exploration Inc.
Ridgewood Energy Corp.
Rim Oil & Gas
Rimel and Rimel
Rio Grande Drilling Co.
River Gas Corp.
Riverstone Holdings LLC.
RMS Monte Christo LLC.
Roch SA.
Rock Ridge Oil & Gas Inc.
Rockford Energy Partners LLC.
Rocky Mountain Gas
Roda Drilling Co.
Roemer Oil Co.
Roff Resources LLC.
Rooster Petroleum LLC.
Rosetta Resources Inc.
Rothchild Oil & Gas
Rowan Cos. Inc.
Royal Gold Inc.
RP UFO International LLC.
RSW Joint Venture
Rushlake Hotels (USA) Inc.
Rutherford Oil Corp.
Ruwco Oil and Gas Corp.
Rag American Coal Holdings Inc.
Rampart Energy Co.
Rancher Energy Corp.
Randall and Dewey
Range Resources Corp.
Reading & Bates Development Co.
Recluse Methane LLC.
Red River Energy
Redexco Company Ventures Ltd.
Redstone Resources Inc.
Reef Energy Co.
Regal Petroleum PLC.
Reliant Energy Wholesale Group
Renaissance Energy Ltd.
Reserve Petroleum U.S.A.
Resource Investors Management Co.
Reunion Energy
RF Energy Corp.
Richland Petroleum Corp.
Ridgelake Energy
Rife Resources Ltd.
Rimco Exploration
Rio Alto Exploration Ltd.
Rio Vista
Riverbend Production LP.
RKI Exploration & Production
Roc Oil Co. Ltd.
Rock Energy Partners
Rock Well Petroleum Inc.
Rockport Energy Corp.
Rocky Point Oil Inc.
Rodinia Oil Corp.
Roemer-Swanson Energy Corp.
Roochester Energy Corp.
Rose Energy Corp.
Rosewood Resources Inc.
Rothfelder & Falick LLP.
Royal Bank of Canada
Royston, Rayzor, Vickery and Will
RTM Gas Company
Rusia Petroleum
Rutherford-Moran Oil Corp.
Ryan, Ryan, Johnson, McCaghey