A respected name in its field, Collarini has been providing upstream consulting services since 1985.  Founded by engineers with major oil and gas company experience, the firm's specialties include reservoir engineering, geoscience, land administration and management, asset development, acquisition evaluation, divestment support, data management, reserve appraisal, and producing asset optimization.


With one of the largest networks of subject matter experts in the industry and a strong leadership background in oil and gas, Collarini has the ability to select the right members for your team.


We help achieve goals, improve asset performance, and are confident in our ability to find solutions to your complex and dynamic challenges.




Cheryl Collarini is a licensed petroleum engineer and Chairman of Collarini Energy Experts, where she manages consulting projects covering a large part of the spectrum of upstream oil and gas. She holds a bachelor's degree in civil engineering from M.I.T. and an MBA from the University of New Orleans. She has over 40 years of experience as a reservoir engineer including teaching Petroleum Investment Decisions for over 20 years for ExxonMobil, Shell, Texaco, and others. Her career includes positions with Mobil Oil and partnerships in Explore Enterprises, where she served as VP of Engineering and in Etroa Resources, where she served as CEO. Cheryl's expertise is in reserves and economics and in project leadership. She has founded a number of companies, including Collarini Energy Staffing in 1995, which offers outsourced services in technical and professional oil and gas disciplines. She is a member of many professional organizations, including the Society of Petroleum Engineers, the Society of Women Engineers, and the Houston Producers' Forum. She is also a member of the Advisory Board of the University of Houston's Petroleum Engineering Department.



Mitch Reece joined Collarini in 2002 and is currently the President of Collarini Associates responsible for the technical organization, managing reserve appraisals, third party reserve reports, and comprehensive field studies. Prior to joining Collarini, Mitch was an independent consultant for Ryder Scott Co., Collarini Engineering, and an International Engineering Manager for Devon Energy. From 1982 to 2000, he held various domestic and international engineering and operations positions for Santa Fe Snyder Corporation and its predecessor, Santa Fe Energy Resources, Inc. Mitch has direct experience in production engineering, reservoir engineering, acquisitions and divestments, field operations, and management of all of those functions. He began his career with Tenneco Oil Company in Lafayette, Louisiana after graduating from Texas A&M in 1979 with a B.S. in Petroleum Engineering. Mitch is a registered Professional Engineer in the state of Texas and a member of the Society of Petroleum Evaluation Engineers (SPEE), Society of Petroleum Engineers (SPE), and the American Petroleum Institute (API).



Volker Rathmann is President of Collarini Energy Experts to which he brings 30 years of business and industry experience. He joined Collarini in 2001 as Vice President of Business Development. Through a series of marketing, sales, and business development campaigns, he led a continually growing E&P staffing business in addition to managing the marketing of the collected expertise of the Collarini companies. Prior to joining Collarini, Volker held the position of Chief Financial Officer for INTEC Engineering, a provider of specialized engineering services in global frontier and deep-water projects. Prior to INTEC Engineering, Volker held a number of management positions in operations, marketing, and finance within Daimler AG. During his tenure with Daimler, he gained the experience and background of managing globally-oriented and growing firms. Volker earned a Bachelor's degree in business administration in Berlin, Germany.