| 5101 | Workover One, Inc. | | Oil & Gas Operator | Jul 1989 |
| 5102 | World Oil & Gas Expl., Inc. | | Oil & Gas Operator | Mar 1988 |
| 5103 | World Producers, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Nov 1994 |
| 5104 | Worldwide Energy Corp. | Freer, TX 78357 | Oil & Gas Operator | Jan 1997 |
| 5105 | Wright Production Company | | Oil Operator | Jun 1990 |
| 5106 | WRT Energy Corporation | Oklahoma City, OK 73118 | Oil & Gas Operator | May 1998 |
| 5107 | WSF, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Jun 2013 |
| 5108 | Wylee Petroleum Corporation | | Oil & Gas Operator | Dec 1984 |
| 5109 | Wynn-Crosby Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2005 |
| 5110 | Wynn-Crosby Operating, LTD. | Dallas, TX 75201 | Oil & Gas Operator | Apr 2025 |
| 5111 | Wytex Production Corporation | Fort Smith, AR 72903 | Oil & Gas Operator | Jan 2020 |
| 5112 | XCL-Louisiana, Inc. | | Oil & Gas Operator | Aug 1993 |
| 5113 | Xeric Oil & Gas Corporation | Midland, TX 79702 | Oil & Gas Operator | Apr 2014 |
| 5114 | Xplor Energy Operating Co. | Houston, TX 77079 | Oil & Gas Operator | Jan 2012 |
| 5115 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Apr 2025 |
| 5116 | Xtra Energy Corporation | | Oil & Gas Operator | Jun 1989 |
| 5117 | Yasny Corporation | | Oil Operator | Nov 1991 |
| 5118 | Yates Oil Company | | Oil Operator | Jul 1990 |
| 5119 | Yellow Dog Oil Company | | Oil Operator | Apr 1988 |
| 5120 | Yellow Rock, LLC | | Oil & Gas Operator | Dec 2024 |
| 5121 | Yentzen Investments, Inc. | Sugar Land, TX 77478 | Oil Operator | May 1993 |
| 5122 | Yentzen Production, Inc. | | Oil Operator | Mar 1987 |
| 5123 | Youngblood Enterprises | | Gas Operator | Dec 1983 |
| 5124 | Youngblood Enterprises, Inc. | | Oil & Gas Operator | Jan 1992 |
| 5125 | Yuma E & P Company, Inc. | Houston, TX 77027 | Oil & Gas Operator | Apr 2025 |
| 5126 | Yuma Petroleum Company | Houston, TX 77027 | Oil & Gas Operator | Aug 2002 |
| 5127 | Z C Ambrose-G L Blaxton, Jr. | | Oil & Gas Operator | Apr 1983 |
| 5128 | Zachry Exploration, Inc. | San Antonio, TX 78205 | Oil & Gas Operator | Apr 2025 |
| 5129 | Zachry Exploration, LLC | San Antonio, TX 78224 | Oil & Gas Operator | Apr 2025 |
| 5130 | Zachry Exploration, LTD. | San Antonio, TX 78205 | Oil & Gas Operator | Jan 2009 |
| 5131 | Zad, Inc. | | Oil Operator | May 2001 |
| 5132 | Zadeck Energy Group Inc | | Oil & Gas Operator | Dec 2011 |
| 5133 | Zam'S Production Company | | Oil Operator | Sep 2004 |
| 5134 | Zarvona Energy LLC | Houston, TX 77002 | Oil & Gas Operator | Apr 2025 |
| 5135 | Zeagler Enterprises, Inc. | | Oil & Gas Operator | Jun 2008 |
| 5136 | Zeit Exploration Co., Inc. | | Oil & Gas Operator | May 1994 |
| 5137 | Zenergy Inc | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2025 |
| 5138 | Zenergy Operating Company, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Dec 2016 |
| 5139 | Zercon Oil & Gas, Inc. | | Oil Operator | Oct 2003 |
| 5140 | Zero Mass Mining, LLC | | Oil Operator | Jan 2025 |
| 5141 | Zgen, Inc. | | Oil & Gas Operator | Jul 1990 |
| 5142 | Zilkha Energy Company | Houston, TX 77046 | Oil & Gas Operator | Oct 2002 |
| 5143 | Zinke & Trumbo, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2007 |
| 5144 | Zinn Petroleum Co. | Houston, TX 77024 | Oil & Gas Operator | Nov 2021 |
| 5145 | Zone Energy, LLC | Houston, TX 77251 | Oil & Gas Operator | Jan 2025 |