Case: 21-10840 Doc: 176 Filed: 05/13/21 Page: 1 of 4 Case: 21-10840 Doc: 176 Filed: 05/13/21 Page: 2 of 4 Case: 21-10840 Doc: 176 Filed: 05/13/21 Page: 3 of 4

EXHIBIT A

Case: 21-10840 Doc: 176 Filed: 05/13/21 Page: 4 of 4

EXHIBIT A Master Service List Served as stated below

Description Creditor Address1 Address2 Address3 Address4 Address5 Email Method of Service Top 30 Amplify Energy Operating LLC 500 Dallas St, Ste 1700 Houston, TX 77002 First Class Mail Top 30 Arkoma Operations LLC 425 W Capital, Ste 3550 Little Rock, AR 72201 First Class Mail NOA - Counsel for United States of America ex rel. Assistant US Attorney Attn: Kay Sewell 210 Park Ave, Ste 400 Oklahoma City, OK 73102 [email protected] Email Office of Natural Resources Revenue, U.S.Department of the Interior (ONRR) NOA - Attorney for Teocalli Exploration, LLC Blaney Tweedy Tipton & Hiersche, PLLC Attn: Eric Odom 204 N Robinson Ave, Ste 1250 Oklahoma City, OK 73102 [email protected] Email NOA - Counsel for Teocalli Exploration, LLC Blaney Tweedy Tipton & Hiersche, PLLC Attn: Justin T. Hiersche 1250 City Place 204 N. Robinson Ave P.O. Box 657 Oklahoma City, OK 7301-0657 [email protected] Email Top 30 Blue Water Resources, LLC 2508 E 71St St, Ste B Tulsa, OK 74136 First Class Mail NOA - Attorneys for Chesapeake Energy Bradford & Wilson PLLC Attn: Reagan E. Bradford 431 W Main St, Ste D Oklahoma City, OK 73102 [email protected] Email Corporation Top 30 Casillas Petroleum Resource Partners, LLC 401 S Boston Ave, Ste 2400 Tulsa, OK 74103 First Class Mail Top 30 Chesapeake Operating, Inc 6100 N Western Ave Oklahoma City, OK 73118 First Class Mail NOA - Proposed Debtor's Counsel Christensen Law Group, PLLC Attn: J Clay Christensen 3401 NW 63rd St, Ste 600 Oklahoma City, OK 73116 [email protected] Email Attn: Jeffrey Tate/ Jonathan Miles [email protected] Attn: Brock Pittman/ Emily Irwin [email protected] [email protected] [email protected] Top 30 Cimarex Energy Co 1700 Lincoln St, Ste 3700 Denver, CO 80203 First Class Mail Top 30 Citizen Energy Iii LLC 320 S Boston Ave, Ste 900 Tulsa, OK 74103 First Class Mail NOA - Attorneys for the State of Louisiana, Civil Division/Lands & Natural Resources Attn: Ryan M. Seidemann Assistant Attorney General Post Office Box 94005 Baton Rouge, LA 70804-9005 [email protected] First Class Mail Department of Natural Resources Email NOA - Attorneys for the State of Louisiana, Civil Division/Lands & Natural Resources Attn: Ryan M. Seidemann Assistant Attorney General 1885 N Third St Baton Rouge, LA 70802 [email protected] Email Department of Natural Resources Top 30 Conocophillips Company 925 N Eldridge Pkwy Houston, TX 77079 First Class Mail Top 30 Contango Resources, Inc 717 Texas Avebue, Ste 2900 Houston, TX 77002 First Class Mail Top 30 Continental Resources, Inc 20 N Broadway Oklahoma City, OK 73102 First Class Mail NOA - Counsel for Simmons Bank Crowe & Dunlevy Attn: Margaret M. Sine 324 N. Robinson Ave., Ste 100 Oklahoma City, OK 73102 [email protected] Email Attn: William H. Hoch, III [email protected] Top 30 Devon Energy Production Company, LP 333 West Sheridan Ave Oklahoma City, OK 73102 First Class Mail Top 30 Enable Midstream Partners 499 W Sheridan Ave, Ste 1500 Oklahoma City, OK 73102 First Class Mail Top 30 Foundation Energy Management, LLC Attn: Eddie W. Rhea 5057 Keller Springs Rd, Ste 650 Addison, TX 75001 First Class Mail NOA - Attorneys for Unbridled Resources, LLC GableGotwals Attn: Craig M Regens One Leadership Sq, 15th FL 211 N Robinson Oklahoma City, OK 73102 [email protected] Email Attn: Dale E Cottingham [email protected] Top 30 Hilcorp Energy Company 1111 Travis St Houston, TX 77002 First Class Mail Top 30 Indigo Minerals LLC 600 Travis St, Ste 5500 Houston, TX 77002 First Class Mail Taxing Authorities Internal Revenue Services Centralized Insolvency Operation P.O. Box 7346 Philadelphia, PA 19101-7346 First Class Mail Top 30 Jma Energy Company, LLC Attn: Michael J. Massad 1021 Northwest Grand Blvd Oklahoma City, OK 73118 First Class Mail Taxing Authorities Louisiana Dept of Revenue Attn: Collection Div, Bankruptcy Section P.O. Box 201 Baton Rouge, LA 70821-0201 [email protected] First Class Mail Email Taxing Authorities Louisiana Dept of Revenue Attn: Collection Div, Bankruptcy Section P.O. Box 66658 Baton Rouge, LA 70896-6658 [email protected] First Class Mail Email Top 30 Mach Ii, LLC Attn: Michael Reel 14201 Wireless Way Oklahoma City, OK 73134 First Class Mail Top 30 Mach Resources, LLC Attn: Greg Dewey 14201 Wireless Way Oklahoma City, OK 73134 First Class Mail Top 30 Magnolia Midstream Gas Services 1 Williams Center P.O. Box 2400, M.D 47 Legal Tulsa, OK 74172 First Class Mail NOA - Counsel for Calhoun County Appraisal District McCreary, Veselka, Bragg & Allen, PC Tara LeDay [email protected] Email

NOA - Counsel for the United States Trustee Office of the United States Trustee Marjorie J. Creasey [email protected] Email NOA - Counsel for Oklahoma County Treasurer Oklahoma County Treasurer Attn: Gretchen Crawford 320 Robert S Kerr, Rm 505 Oklahoma City, Okla 73102 [email protected] Email Taxing Authorities Oklahoma Tax Commission Attn: General Counsel's Office 100 N Broadway Ave, Ste 1500 Oklahoma City, OK 73102-8601 First Class Mail Taxing Authorities Oklahoma Tax Commission Attn: General Counsel's Office 2501 N Lincoln Blvd Oklahoma City, OK 73194 First Class Mail NOA - Counsel for MarkWest Oklahoma Gas Polsinelli PC Attn: Ghislaine G. Torres Bruner 1401 Lawrence St, Ste 2300 Denver, CO 80202 [email protected] Email Company, LLC NOA - Attorney for Casillas Petroleum Resource Pray Walker, PC Attn: Kevin P. Doyle 100 W 5th St, Ste 900 Tulsa, OK 74103 [email protected] Email Partners, LLC and CPRP Services, LLC, et al. Attn: Robert J Winter [email protected] Top 30 Presidio Petroleum LLC 500 W 7th St, Ste 803 Fort Worth, TX 76102 First Class Mail Litigation Rhb Inc 6608 N Western Ave Oklahoma City, OK 73116 First Class Mail Top 30 Riviera Operating, LLC 717 Texas Ave, Ste 2000 Houston, TX 77002 First Class Mail Top 30 Sandridge Exploration & Production LLC 1 East Sheridan, Ste 500 Oklahoma City, OK 73104 First Class Mail Top 30 Scout Energy Management 4901 Lbj Freeway, Ste 300 Dallas, TX 75244 First Class Mail Top 30 Teocalli Exploration, LLC 6608 N Western Ave Oklahoma City, OK 73116 First Class Mail Top 30 Territory Resources LLC Attn: Legal Dept 1511 S Sangre Rd Stillwater, OK 74074 First Class Mail Taxing Authorities Texas Comptroller of Public Accounts P.O. Box 13528 Capitol Station Austin, TX 78711-3528 [email protected] First Class Mail Email NOA - Local counsel for MarkWest Energy Partners, The Gooding Law Firm A Professional Corporation Mark B. Toffoli [email protected] Email L.P/Local counsel for MarkWest Oklahoma Gas Company, LLC Top 30 Trinity Operating (Usg), LLC 601 Travis St, Ste 1900 Houston, TX 77002 First Class Mail US Attorney's Office for Western District of U.S. Attorney's Office Western District of Oklahoma 210 W Park Ave, Ste 400 Oklahoma City, OK 73102 First Class Mail Oklahoma Top 30 Unbridled Resources LLC 1111 Bagby St, Ste 1600 Houston, TX 77002 First Class Mail Taxing Authorities Virginia Dept of Taxation Attn: Business/Compliance P.O. Box 1500 Richmond, VA 23218-1500 First Class Mail Top 30 Weatherly Oil & Gas, LLC 4849 Greenville Ave, Ste 1250 Dallas, TX 75206 First Class Mail Top 30 Williams Midstream Gas Services LLC 1 Williams Center P.O. Box 2400, M.D 47 Legal Tulsa, OK 74172 First Class Mail Counsel to Simmons Bank, Secured Lender Winstead PC Attn: Clint Bodien 500 Winstead Bldg 2728 N Harwood St Dallas, TX 75201 [email protected] First Class Mail Email Top 30 Xto Energy, Inc 22777 Springwoods Village Pkwy Spring, TX 77389 First Class Mail

Dorchester Resources, L.P. (21-10840