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Thomas G. Hill, JR.


Mr. Hill holds a Mechanical Engineering degree from the University of Houston. He founded Tejas in 1999 and conceived the development of the test laboratory systems and construction of the HPHT test bunkers. Previously Tom worked for Camco/Schlumberger, where he designed many new SCSSV’s, which are still being used today. Mr. Hill has been awarded and has filed numerous patents. At Tejas, Tom is active in Business Development, reporting to the CEO.

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Robert C. Henschel, JR.

Chief Operating Officer

Robert began his oilfield career at Camco (SLB) developing, testing and servicing SCSSV’s. At Tejas, he has managed the successful development of downhole completion products, including the SCSSV product line for Weatherford International and BJ Services. In addition to his project management responsibilities, Robert is also the Quality Management Rep, and has been instrumental in establishing each of the API monogram licenses Tejas holds today. Mr. Henschel received his BSME from the University of Texas at El Paso. At Tejas, Robert serves as COO, responsible for Management of Projects & Operations.

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Sebastian Nienhuis

Director of Technology and Lab Operations

Sebastian began his technology career in the telecommunications industry supporting the infrastructure of a premier U.S. coast-to-coast long distance fiber optic carrier. Moving into the online services industry, he served in various project management roles supporting international data center deployments, domestic data center migrations, new product launches and operational improvement initiatives. Leveraging his experience, as Director of Live Operations, Sebastian helped build a startup online service business growing from 25 to 500+ employees, supporting an international organization on a globally dispersed infrastructure backbone. Sebastian joined the Oil Field Industry and Tejas in 2011. He is the Director of Technology and Lab Operations, responsible for information technology as well as developing and managing the testing services organization. Sebastian has a BS in Computer Science from the University of Houston at Victoria.

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Mark Moon


Mark holds a master’s degree in Professional Accountancy from Stephen F. Austin State University.  While attending the University, he was a prominent member of Beta Alpha Psi, an international honor society for accounting students.  Mark began his career in public accounting working for one of Houston’s largest CPA firms. While working at the firm, his first assignment was performing the financial audit for Tejas Research & Engineering, LLC. Mark led the Tejas audit engagement for 6 years and later joined the Tejas Management team as Controller in 2020. Mark oversees the accounting department and is responsible for all financial matters.

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Case Nienhuis

Chief Executive Officer

Case started his career with Halliburton as trainee in well bore construction and drill stem testing. He then joined Camco (now Schlumberger) serving in various leadership roles for downhole completions (safety valves, production packers, artificial lift systems and wireline) with emphasis on operations in the Middle East and on business development globally. Mr. Nienhuis led Domestic Business Development at Universal Compression and International Operations at Weatherford Global Compression (now Exterran) with focus on improving gas gathering, gas transmission and gas storage projects. Prior to joining Tejas, he led Business Development at Maverick Engineering, developing projects for upstream production facilities optimization. Mr. Nienhuis is an Automotive Engineering and Business Management graduate from the IVA Institute of The Netherlands. Case serves as Tejas’ CEO, responsible for Sales and General Management

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Jason Mailand, P.E., PMP

Director of New Product Development

Jason holds BS and MS degrees both in Mechanical Engineering from the University of California with emphasis on Mechanics of Materials. He started his oilfield career with Camco/ Schlumberger taking products from design to installation. Prior to joining Tejas, Mr. Mailand held critical engineering positions and Canyon Offshore/ Helix in robotic subsea services. Jason has proven expertise in conceptualization and development, which many new downhole patents issued. At Tejas, Jason serves as Director of New Product Development (NPD), responsible for delivering new product developments.

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Daniel Rojas

Director of Business Development

Daniel Rojas is a distinguished member of Tejas Research & Engineering’s staff.  He graduated with a BS in Mechanical Engineering from the University of North Carolina - Charlotte in 1985 and brings over 37 years of Oil & Gas experience to Tejas’ team. Mr. Rojas has expertise in downhole completions equipment, holds several patents in this technology space and brings a wealth of experience in wellbore analysis and design, operations, sales, field service, management, training, and tool design. His experience includes offshore and land-based operations, both in international and US markets. His history of bringing new and disruptive completion technology to the market aligns perfectly with Tejas’ strategic objectives. He has previously worked for and held management and operations positions at Guiberson, Camco, Halliburton, Johnson Screens, Weatherford, Packers Plus, Suretech/Sanjel, and Co-Founder of Stage Completions. Daniel joined Tejas Research & Engineering in 2023 as Director of Business Development.

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