Exploration & Production

About Us

Alta Mar Energy, LLC is a full-cycle, upstream company focused on non-operated investments in the U.S. Gulf of Mexico. With a flexible mandate and significant financial backing from Carnelian Energy Capital Management, L.P., we partner with best-in-class offshore operators in exploration, development and production projects.


Will Sims

Chief Executive Officer

Will is Chief Executive Officer of Alta Mar Energy, LLC. He was previously Vice President, Business Development at Kosmos Energy where he focused on the company’s Gulf of Mexico assets. Before Kosmos Energy, Will served as Commercial Manager for Deep Gulf Energy, a private equity backed Gulf of Mexico operator that was sold in 2018 for $1.225 billion. He started his career at Noble Energy working in various commercial and business development roles in West Africa and the Gulf of Mexico. Will graduated with a B.B.A. in Finance and Energy Management from the University of Oklahoma and holds a J.D. from South Texas College of Law.

Ben Heller

Chief Financial Officer

Ben is Chief Financial Officer of Alta Mar Energy, LLC.  He has over a decade of energy investment banking experience, previously serving in the Houston Natural Resources Group at Barclays. During his time at Barclays, Ben focused on E&P and minerals, advising clients on over $50 billion of M&A, high yield, and equity transactions. He began his career at Netherland, Sewell & Associates as a petroleum analyst. Ben graduated from Washington and Lee University with a B.S. in Business Administration with honors.  He is a CFA charterholder.

Rowland Burno

Senior Vice President, Engineering

Rowland is Senior Vice President, Engineering of Alta Mar Energy, LLC. He was previously Senior Vice President, Engineering for Venari Resources, LLC, where he led a staff responsible for technical and economic evaluations, reserve reporting, development planning and reservoir modeling in the Gulf of Mexico. Rowland spent 12 years with Nexen Petroleum U.S.A. Inc., where he held positions in deep water exploration engineering, appraisal and planning management, and as vice president for technical assurance. He started his career at ARCO and held progressive reservoir, operations and analytical engineering roles in Alaska, the Middle East and Brazil. Rowland earned a B.S. in Petroleum Engineering from Stanford University. He is a member of the Society of Petroleum Engineers.

Thomas Kastner

Senior Vice President, Geoscience

Tom is Senior Vice President, Geoscience for Alta Mar Energy, LLC. He was previously in a senior technical position at Kosmos Energy focused on Gulf of Mexico exploration strategy, subsurface evaluation and prospect generation. Prior to Kosmos, Tom was a partner at Arena Energy where he was responsible for geoscience activities associated with the development of several shallow water Gulf of Mexico fields. Before Arena, he held various technical and management roles at Noble Energy working on exploration activities in the company’s Gulf of Mexico and Africa business units. Tom began his career at Anadarko Petroleum. Tom holds a B.S. in Geology from Southern Illinois University and an M.S. in Petroleum Geochemistry from the University of South Carolina.

Company News

First Oil Production Announced at Winterfell in the U.S. Gulf of Mexico

DALLAS–(BUSINESS WIRE)–Jul. 3, 2024– Kosmos Energy Ltd. (“Kosmos” or the “Company”) (NYSE/LSE: KOS) announced today the successful start-up of oil production at the Winterfell development in the Green Canyon area of the U.S. Gulf of Mexico. Winterfell (Kosmos 25.04% working interest) is a phased development with the initial two production wells of the first phase now online and ramping up production. … Read More

Alta Mar Invests in Winterfell Development in the Gulf of Mexico

Houston, TX, January 10, 2024. Beacon Offshore Energy LLC (“Beacon”), announced today that several of its subsidiaries have taken final investment decision to develop the Winterfell discovery which is operated by BOE Exploration & Production LLC (“BOE”) and will be developed as a cost effective/low emissions subsea tieback. As the Winterfell operator, Beacon holds a … Read More

Alta Mar Energy and Carnelian Energy Capital Management, L.P. Form Gulf of Mexico Focused Partnership

HOUSTON (July 11, 2023) – Alta Mar Energy, LLC (“Alta Mar”) today announced the closing of an equity commitment from investment funds managed by Carnelian Energy Capital Management, L.P. (“Carnelian”). Alta Mar, a Houston-based company led by Will Sims, Thomas Kastner, Rowland Burno and Ben Heller, will leverage the team’s decades of diverse offshore experience … Read More

Contact Us

Alta Mar Energy, LLC

TotalEnergies Tower
1201 Louisiana Street, Suite 730
Houston, TX 77002-5600
United States of America