top of page


Company History

Cardinal River Energy Company was founded in 1987 as a small exploration and production company. In late 2006, the company formed a strategic partnership with several privately held Oklahoma City based energy companies. These companies consolidated their oil and gas interests into Cardinal River Energy I LP. Through its early years, the company focused its business strategy on being a low cost, non-operating working interest owner in a diverse portfolio of oil and gas assets. As the company continued to grow and began generating its own prospects, the company formed Cardinal River Operating, LLC as an operating affiliate to drill, manage and operate the company's internally generated prospects.   Today, as a result of the general partner's selective acquisition and participation strategies, the Partnership now owns operated and non-operated working interests, royalty interests and overriding royalty interests in over 1000 wells and properties located in several states including Oklahoma, Kansas, Arkansas, Texas, New Mexico, Mississippi, Illinois and Louisiana.

Cardinal River Energy is also the parent company of River Rock Energy Company and River Rock Operating, LLC.  River Rock Energy owns over 2,000 oil and gas wells in Oklahoma and Kansas, with over 2,300 miles of gas gathering and gas processing assets.  River Rock Operating, LLC is the operator of all of River Rock Energy's wells and gas gathering assets.

Brian Cardell


Mr. Cardell joined Cardinal River Energy in 2013 as Vice President of Finance. In 2014, he was promoted to Chief Financial Officer, and in 2019 he purchased the assets of Cardinal River and assumed the role of President.   During his time at Cardinal River, he has focused on lean asset management along with growth generated by internal cash flows.  In 2016, Mr. Cardell was part of the managment team that acquired troubled assets consisting of approximately 2,000 natural gas wells, which the company has since made profitable and continues to operate.  In his role at Cardinal River, Mr. Cardell is responsible for the oversight over all of the company's business affairs.  Prior to joining the company, he was with PricewaterhouseCoopers, LLP in Atlanta where he worked in the assurance practice as a member of the financial services group.

Mr. Cardell is a licensed Certified Public Accountant and holds a Bachelor of Business Administration from the Goizueta Business School at Emory University in Atlanta with a concentration in accounting. 


Jay C. Jimerson

Manager & General Counsel

Mr. Jimerson joined the company in 2005 after spending several years as an energy lawyer, and thereafter as a managing partner in a Houston based energy firm.  He was President of Cardinal River Energy Co. for several years until transitioning to Manager and General Counsel in 2019.  From 1984 until 1996, Mr. Jimerson was a member of the Oklahoma City law firm of Mock, Schwabe, Waldo, Elder, Reeves & Bryant. While in private practice, Mr. Jimerson practiced in the areas of oil and gas state regulation, oil and gas litigation, gas marketing and transportation, and underground natural gas storage development and operation. He has experience in a variety of energy related areas, including well permitting and drilling, land and legal, oil and gas marketing and hedging, insurance and environmental matters.

In 1996, Mr. Jimerson became general counsel, managing director and a principal of eCORP, LLC, a privately held energy company based in Houston, Texas. While at eCORP, Mr. Jimerson was involved in the development and marketing of underground natural gas storage assets and other energy related assets. He has substantial experience with respect to state and federal permitting and development of natural gas storage and transportation assets.

Mr. Jimerson has been the past President of the Mineral Law Section of the Oklahoma Bar Association, and has been the author of several articles and papers relating to energy law issues. He holds a Bachelor of Business Administration Degree (with distinction) from the University of Oklahoma, a Juris Doctor Degree (with honors) from the University of Oklahoma School of Law, and is a graduate of the Owner/President Management Program at Harvard Business School. He is also an Advisory Board Member of the OU Price Business College Energy Institute. 

Brandon Donovan

Manager of Operations

Brandon Donovan has many years of experience as an operations and drilling engineer.   Prior to joining Cardinal River Energy, Mr. Donovan worked as a mechanical engineer and well planner for Great White Directional Services and Intrepid Directional Drilling.   Thereafter, he worked at Chesapeake Energy Corporation as a drilling engineer in the Barnett Shale and Eagle Ford basins.  While at Chesapeake, Mr. Donovan was responsible for well planning for over 75 wells in the Barnett Shale and Eagle Ford areas, prepared well AFEs, and managed drilling operations.  Prior to 2019, Mr. Donovan was a drilling and operations engineer at Cardinal River Energy.  In 2019 Mr. Donovan became the Manager of Operations at both Cardinal River Operating, LLC and River Rock Operating, LLC.  He graduated in 2005 from Oklahoma State University with a Bachelor of Science, Mechanical Engineering Technology, and has completed several specialty courses in well planning, well control, drilling fluids, etc.


Austin Wentroth


Mr. Wentroth joined Cardinal River Energy in 2021 as the Controller.  He has seven years of experience in the upstream oil and gas industry and 12 years of accounting experience.  Prior to joining Cardinal River, Mr. Wentroth was the Controller at Red Wolf Natural Resources, an Oklahoma based exploration and production company.  Prior to Red Wolf, Mr. Wentroth was a Senior Financial Analyst at Compass Production Partners.  Mr. Wentroth graduated from Oklahoma State University with an accounting degree and earned his Masters Degree in Business Administration from Mid-America Christian University.  

Christina Donovan

Executive Assistant/Office Manager, Cardinal River Energy Company

Ms. Donovan joined Cardinal River Energy in 2010 as an Executive Assistant. She also currently serves as Office Manager for the company. While at Cardinal River, Ms. Donovan has worked in various areas, including office administration, land, joint interest accounting, division orders and administrative legal support.

She holds a Bachelor of Science Degree in Biology from the University of Central Oklahoma.


Tracy Allen 


Mrs. Allen has over 20 years of experience in oil and gas accounting matters.  Prior to joining Cardinal River Energy, Mrs. Allen spent two years with Marlin Oil Corporation, an Oklahoma based oil and gas operator that operated over 150 wells in Oklahoma and Texas.  While working at Marlin Oil Corp., Mrs. Allen was responsible for all JIB accounting functions.  In addition to her work at Marlin Oil Corp., Mrs. Allen has also been responsible for all revenue and expense accounting matters for Red Rock Resources, LLC, a family owned Oklahoma based operator of oil and gas wells.  At Red Rock Resources, Mrs. Allen became very proficient in the use of the SSI Oil and Gas Accounting System.  Since joining Cardiinal River Energy, Mrs. Allen has been responsible for all revenue and expense classification and data entry, payroll, payroll taxes, joint interest billings and revenue distribution.  Mrs. Allen earned a Petroleum Engineering Degree from Marietta College.  However, she has spent most of her career working in the area of oil and gas accounting 

Roman Mauer

Production Engineer 

Mr. Mauer began his career as a Production Engineer at PostRock Energy Corporation where he was responsible for overseeing day-to-day production and field operations.    As a production engineer, Mr. Mauer designed and supervised workovers, completions/recompletions, chemical treatments and other field operations and maintenance procedures.   After several years at PostRock Energy, Mr. Mauer joined Cardinal River Energy in 2015 as a Production Engineer.  While at Cardinal River Energy, Mr. Mauer has been responsible for overseeing workovers, production and operations for over 2,000 oil and gas wells and 90 salt water disposal wells owned by Cardinal River Energy or River Rock Energy.  He continues to be involved in the design of well completions and recompletions, as well as the design and installation of surface facilities including artificial lift equipment in both vertical and horizontal wellbores.

Mr. Mauer earned a Bachelor of Science Degree in Petroleum Engineering from the University of Oklahoma.


Kristy Isaacson

Division Order Analyst/Land

Kristy Isaacson has over 16 years of experience in the oil and gas industry in a variety of positions.   She has worked in both the upstream and midstream sectors of the oil and gas industry with prior positions at EXOK, Inc., Access Midstream (formerly Chesapeake Midstream), and PostRock Energy Corporation.   Kristy has experience in acquisitions and divestitures, contract review and administration, division orders and land work.   She joined River Rock Energy in 2016, where she is responsible for all division orders and transfer orders, maintenance of ownership decks, landowner relationships, and a variety of other land matters.

Mandy Pregler

Accounts Payable Manager

Mrs. Pregler has over 25 years of experience in managing accounts payables for oil and gas companies.  She worked for over 10 years in accounts payable at PostRock Energy Corporation where she was promoted to Accounts Payable Supervisor and eventually Accounts Payable Manager.   Mrs. Pregler joined River Rock Energy in 2016 where she has been responsible for managing and supervising all accounts payable matters.   In her capacity as Accounts Payable Manager, she also has extensive experience in oil and gas ad valorem tax matters in both the upstream and midstream sectors. 


Kit Daggs

General Ledger Accountant

Kit Daggs has worked in the General Ledger accounting field for over 25 years and has worked in the oil and gas industry for over 15 years.  She joined River Rock Operating/River Rock Energy in 2016.  Responsibilities include analyzing and posting all journal entries related to General Ledger accounts and Accounts Receivable.  Other duties include posting all cash transactions, daily cash reconciliation, monthly reconciliation of cash and prepaid accounts, and performing month-end and year-end close for River Rock Operating and River Rock Energy.  Prior to joining River Rock, Kit’s oil and gas accounting experience includes General Ledger accounting at PostRock Energy and Regional Accounting Administrator at J-W Energy. 

Chelsea Madsen


Mrs. Madsen has several years of experience in oil and gas accounting data entry and administration matters.  She joined River Rock Energy in 2016 in the Accounts Payable Department where she oversaw vendor maintenance, invoice processing and account reconciliation matters.  In 2019 she assumed a greater role as she became responsible for all oil and gas sales and revenue accounting, including royalty owner distributions to over a thousand royalty owners.  She also coordinates all royalty related communications with royalty owners.   Mrs. Madsen received a Bachelor of Science Degree in Early Childhood Education from Northwestern Oklahoma State University, and she is proficient in the SSI Revenue Accounting software system.  

bottom of page