| RG Exploration, LLC | 104375 | Midland | 3 | 1 |
| Rheem Mfg Co | 101857 | — | 1 | 1 |
| Rhine Petroleum | 101858 | — | 1 | 1 |
| Riata Energy Inc | 101859 | Amarillo | 6 | 2 |
| Rich, E S | 101860 | — | 2 | 1 |
| Richardson Operating CoActive | 101862 | Denver | 1 | 1 |
| Richardson Operating CompanyActive | 101861 | Denver | 5 | 2 |
| Richfield Oil Corp | 101863 | — | 0 | 0 |
| Richfield Resources LLC | 101864 | Salt Lake City | 1 | 1 |
| Rig II LLC | 101865 | Woods Cross | 3 | 1 |
| Rim Operating IncActive | 101866 | Farmington | 0 | 0 |
| Rim Operating IncActive | 101867 | Englewood | 7 | 1 |
| Rim Southwest CorpActive | 101868 | Farmington | 9 | 1 |
| Rimrock Mines Inc | 101869 | — | 1 | 1 |
| Rio Bravo Oil Company | 101870 | Park City | 2 | 1 |
| River Gas Corporation | 101871 | Price | 0 | 0 |
| River Gas Corporation | 101872 | Tuscaloosa | 17 | 2 |
| River Gas of Utah Inc | 101873 | Northport | 2 | 1 |
| Riviera Operating, LLC | 104846 | — | 0 | 0 |
| RME Petroleum Company | 101875 | Houston | 33 | 2 |
| Road Runner Inc | 101876 | Park City | 4 | 1 |
| Robert L Bayless Producer, LLCActive | 101877 | Denver | 69 | 4 |
| Robert P Vernon | 101878 | College Station | 0 | 0 |
| Roberts, J E Jr | 101879 | — | 1 | 1 |
| Robertson, Jack R | 101880 | Salt Lake City | 1 | 1 |
| Roberty | 105218 | — | 0 | 0 |
| Robinson, R D | 101881 | — | 1 | 1 |
| Rock Creek Land and Energy | 101883 | Franktown | 0 | 0 |
| Rockies Standard Oil Company | 101884 | Provo | 4 | 1 |
| Rockwell Oil Co | 101885 | — | 1 | 1 |
| Rocky Mountain Energy, LLC | 104340 | Murray | 0 | 0 |
| Rocky Mountain Explor Co | 101886 | Salt Lake City | 1 | 1 |
| Rocky Mt Operating Co Inc | 101888 | Littleton | 0 | 0 |
| Roddy Production Company Inc | 101889 | Farmington | 0 | 0 |
| Roemer Oil Company | 101890 | Denver | 0 | 0 |
| Rogan Et Al | 101891 | — | 1 | 1 |
| Romex Corporation | 101892 | — | 1 | 1 |
| Rooney Operating Co | 101893 | Englewood | 2 | 1 |
| Rose Petroleum (US), LLC | 101895 | Parker | 2 | 1 |
| Rose Petroleum (Utah) LLCActive | 101894 | Annapolis | 10 | 1 |
| Rose, Verl | 101896 | Spring Creek | 1 | 1 |
| Roseland Oil & Gas Inc | 101897 | Tulsa | 3 | 1 |
| Rosen Oil Co | 101898 | Wichita | 1 | 1 |
| Rosewood Resources IncActive | 101899 | Dallas | 69 | 1 |
| Ross Exploration Inc | 101900 | Roosevelt | 0 | 0 |
| Ross Operating & Mgmt Co | 101901 | Shreveport | 0 | 0 |
| Rossberg, Kenneth | 101902 | Kearns | 1 | 1 |
| Rover Operating, LLC | 105570 | Artesia | 0 | 0 |
| Royal Oil Development Co | 101903 | — | 1 | 1 |
| Royal Resources Corp | 101904 | — | 1 | 1 |
| Royale Energy Inc | 101905 | San Diego | 9 | 2 |
| Royale Energy Inc | 101906 | San Diego | 0 | 0 |
| Royalite Petroleum Corporation | 101907 | Austin | 2 | 1 |
| Royce R Latimer | 101908 | Moab | 1 | 1 |
| Royster, Harry | 101909 | — | 10 | 1 |
| RSOC Cisco Dome, LLC | 104992 | Grand Junction | 0 | 0 |
| Ruby, Glen Et Al | 101910 | — | 6 | 1 |
| Ruddick, A B | 101911 | — | 1 | 1 |
| Running Foxes Petroleum, IncActive | 101912 | Centennial | 82 | 1 |
| Ryan, V Pat | 101913 | — | 1 | 1 |
| Ryder Scott Oil Co | 101914 | — | 1 | 1 |
| S & S Mining Co | 101915 | — | 1 | 1 |
| S Fox Company | 101916 | — | 2 | 1 |
| S O A L LLC | 101917 | Farmington | 1 | 1 |
| S O Utah | 101918 | Irvine | 3 | 1 |
| S W Energy Corporation | 101919 | Salt Lake City | 11 | 1 |
| Sagadahoc Oil & Gas | 101921 | — | 3 | 1 |
| Sage Energy Company | 101922 | Duarty | 1 | 1 |
| Sage Potash (USA Corp)Active | 105374 | South Jordan | 3 | 1 |
| Sage Valley Oil Co | 101923 | — | 2 | 1 |
| Sage Water Resources, LLCActive | 104573 | Duchesne | 1 | 1 |
| Sam Oil Inc | 101924 | Roosevelt | 3 | 2 |
| Samedan Oil Corporation | 101925 | Houston | 24 | 4 |
| Samedan Oil Corporation | 101926 | Denver | 0 | 0 |
| Samedan-Apco | 101927 | Oklahoma City | 1 | 1 |
| Samson Resources Company | 101928 | Tulsa | 21 | 4 |
| San Francisco | 101929 | — | 9 | 1 |
| San Juan Casing Pullers | 101930 | Farmington | 0 | 0 |
| San Juan Minerals Explor | 101931 | Mexican Hat | 47 | 1 |
| San Juan Oil & Refining | 101932 | — | 1 | 1 |
| San Juan Oil Co | 101933 | — | 1 | 1 |
| San Rafael Oil Co | 101934 | — | 1 | 1 |
| Sanchez-Obrien Oil & Gas | 101935 | — | 2 | 1 |
| Sand Oil Company | 101936 | Salt Lake City | 1 | 1 |
| Sandburg Petroleum Co | 101937 | — | 1 | 1 |
| Sanpete Oil Co | 101938 | — | 2 | 2 |
| Santa Fe Energy Company | 101939 | Houston | 10 | 3 |
| Santa Fe Snyder Corp | 101940 | Baggs | 0 | 0 |
| Santana Exploration | 101941 | Cortez | 0 | 0 |
| Sapient Energy Corp | 101942 | Tulsa | 6 | 1 |
| Sarco Oil Properties LLC | 101943 | — | 0 | 0 |
| Saturn Resources Corp | 101944 | Springboro | 2 | 1 |
| Sauer Drilling Company | 101945 | Casper | 0 | 0 |
| Savant Resources LLC | 101946 | Denver | 0 | 0 |
| Savoy Energy, LLCActive | 101947 | Ephraim | 4 | 2 |
| Saxon Oil Company | 101948 | Dallas | 3 | 1 |
| Schalk, John E | 101949 | — | 2 | 1 |
| Schneir, Ronald & Assoc | 101950 | Denver | 1 | 1 |
| Schroth, C M & Assoc | 101952 | — | 1 | 1 |
| Schurr, Dickinson & Gregg | 101953 | Cortez | 0 | 0 |
| Schuster Homes Inc | 101954 | Rangely | 0 | 0 |
| Schweikhart, H A | 101955 | — | 1 | 1 |
| Scout Energy Management, LLCActive | 105311 | Dallas | 3,231 | 2 |
| Scurlock Permian LLC | 101956 | Houston | 0 | 0 |
| Seaboard Oil Co of Del | 101957 | Casper | 1 | 1 |
| Security Energy Company | 101959 | Houston | 0 | 0 |
| Seeley Oil Company | 101960 | Salt Lake City | 0 | 0 |
| Seeley Oil Company, LLCActive | 101961 | Cortez | 24 | 3 |
| Seeligson, A A Jr | 101962 | — | 1 | 1 |
| Sego Resources Corp | 101963 | Denver | 1 | 1 |
| Sei Energy LLC | 101964 | Chattanooga | 0 | 0 |
| SEP Cisco Dome II, LLCActive | 101965 | Orem | 13 | 1 |
| SEP Cisco Dome LLC | 101966 | Orem | 4 | 1 |
| SEP Cisco Dome LLC | 101967 | South Jordan | 0 | 0 |
| SEP NOSR LLCActive | 104509 | Orem | 2 | 1 |
| Sep-Agate LLC | 101968 | South Jordan | 0 | 0 |
| Service Drilling Co | 101969 | — | 1 | 1 |
| Service Oil Company | 101970 | Salt Lake City | 1 | 1 |
| Sevier Exploration, LLC | 104439 | — | 0 | 0 |
| Sfeop | 101971 | Midland | 1 | 1 |
| Shallow Oil Co | 101972 | Vernal | 1 | 1 |
| Shamrock Oil & Gas Corp | 101973 | — | 0 | 0 |
| Sharples Oil Co | 101974 | — | 1 | 1 |
| Sharples, Phillip T Trust | 101975 | Denver | 0 | 0 |
| Shear, Charles A | 101976 | Grand Junction | 0 | 0 |
| Sheffield Exploration Co | 101977 | Denver | 0 | 0 |
| Shell Oil Company | 101978 | Houston | 124 | 11 |
| Shell Trading (US) Co | 101979 | Houston | 0 | 0 |
| Shell Western E&P Inc | 101980 | — | 0 | 0 |
| Shelly, L G | 101981 | San Antonio | 1 | 1 |
| Sheltered Security & Mgmt | 101982 | Salt Lake City | 0 | 0 |
| Shenandoah Energy Inc | 101983 | Denver | 126 | 2 |
| Shenandoah Energy Inc | 101984 | Vernal | 0 | 0 |
| Shenandoah Oil Corp | 101985 | Denver | 6 | 2 |
| Shepler & Thomas Inc | 101986 | Evergreen | 1 | 1 |
| Sherwin Artus Inc | 101987 | Golden | 2 | 1 |
| Shiny One Operating Company, LLCActive | 101988 | Vernal | 11 | 1 |
| Shiprock Oil & Gas | 101989 | Farmington | 0 | 0 |
| Shogun Oil Inc | 101990 | Roosevelt | 0 | 0 |
| Shumway Uranium & Mining C | 101991 | — | 2 | 2 |
| Sial Exploration | 101992 | Englewood | 0 | 0 |
| Sierra Madre Oil Co | 101993 | — | 1 | 1 |
| Silengo, Charles L | 101994 | — | 0 | 0 |
| Silver Exploration Co | 101995 | Hood River | 1 | 1 |
| Silver Gull Oil & Gas Co | 101996 | — | 1 | 1 |
| Simms, Clarke N | 101997 | — | 2 | 1 |
| Sinclair Oil & Gas Co | 101998 | — | 11 | 3 |
| Sinclair Oil & Gas Company | 101999 | Salt Lake City | 0 | 0 |
| Sinclair Oil Corporation | 102000 | Salt Lake City | 34 | 4 |
| Sitton, F A | 102001 | — | 1 | 1 |
| Skelly Oil Co | 102002 | — | 20 | 5 |
| Sky-High Oil Company | 102003 | — | 1 | 1 |
| Skyline Oil Company | 102004 | Salt Lake City | 12 | 3 |
| Skyline Operating Company, LLCActive | 102005 | Alpine | 2 | 1 |
| Slaback, A A | 102006 | — | 1 | 1 |
| Slate River Resources LLC | 102007 | Denver | 26 | 2 |
| Slate River Resources LLC | 102008 | Vernal | 0 | 0 |
| Slaughter, Orville | 102009 | — | 1 | 1 |
| SM Energy CompanyActive | 105559 | Denver | 567 | 2 |
| SM Gas Production Inc | 102010 | Farmington | 4 | 1 |
| Smith | 102011 | — | 1 | 1 |
| Smith, Howard | 102012 | — | 1 | 1 |
| Smoot, Richard P | 102013 | Salt Lake City | 2 | 1 |
| Snyder Oil Company | 102014 | Denver | 11 | 2 |
| Snyder Oil Corporation | 102015 | Baggs | 37 | 2 |
| Snyder Operating Company | 102016 | Denver | 0 | 0 |
| So Western-Arkansas Co Inc | 102017 | — | 0 | 0 |
| Sohio Petroleum Co | 102018 | Casper | 1 | 1 |
| Sohio-Stand Oil Prod Co | 102019 | Houston | 11 | 4 |
| Sojourner Exploration Co | 102020 | Abilene | 1 | 1 |
| Solaris Exploration Corp | 102021 | Houston | 0 | 0 |
| Soli Deo Gloria Petroleum LLC | 102022 | Frisco | 1 | 1 |
| Sonat Exploration Co | 102023 | Houston | 3 | 1 |
| Sonic Petroleum Corp | 102024 | — | 1 | 1 |
| South Louisiana Prod Co | 102025 | Denver | 1 | 1 |
| Southern CA Mergers & Acq | 102027 | Los Angeles | 0 | 0 |
| Southern Natural Gas Co | 102028 | Houston | 2 | 1 |
| Southern Production | 102029 | — | 1 | 1 |
| Southern Royalty Co | 102030 | Ft Worth | 1 | 1 |
| Southern Union Exploration | 102031 | Farmington | 1 | 1 |
| Southern Union Production | 102032 | Farmington | 2 | 2 |
| Southern Union Refining | 102033 | Hobbs | 0 | 0 |
| Southern Utah | 102034 | — | 1 | 1 |
| Southland Royalty CoActive | 102035 | Englewood | 19 | 4 |
| Southside Oil Co | 102036 | — | 1 | 1 |
| Southwest Oil Co | 102037 | — | 1 | 1 |
| Southwestern Energy Production Company | 102038 | Houston | 2 | 1 |
| Southwestern Energy Ventures Company, LLC | 102039 | Bayfield | 0 | 0 |
| Southwestern Production | 102040 | Denver | 0 | 0 |
| Special T*S Management Inc | 102041 | Aztec | 0 | 0 |
| Speerex LTD Partnership | 102042 | Roswell | 0 | 0 |
| Spencer, P C | 102043 | — | 1 | 1 |
| Split Mountain Oil Inc | 102044 | Unknown | 0 | 0 |
| Split Rock Oil Inc | 102045 | Casper | 0 | 0 |
| Spokane Oil Co | 102046 | — | 1 | 1 |
| Spooner Petroleum Company | 102047 | Ridgeland | 0 | 0 |
| St Anselm Exploration Co | 102048 | Denver | 0 | 0 |
| St Croix Exploration | 102049 | Minneapolis | 4 | 1 |
| St George Oil Company | 102050 | — | 3 | 1 |
| St Louis Car Co | 102051 | Farmington | 1 | 1 |