Chairman and Chief Executive Officer
Nelson Martínez graduated with a bachelor’s degree in chemistry (1973) and a master’s degree in physical chemistry (1974) from France’s University of Poitiers. He subsequently obtained a doctorate in chemistry from the University of Reading in the United Kingdom in 1978 and a master’s degree in technology management from the Massachusetts Institute of Technology (MIT) in 1993. Additionally, he has pursued management studies at Michigan and Harvard universities and at the nonprofit research institute, SRI International, in California.
Martínez began his career with Petróleos de Venezuela, S.A. (PDVSA) in 1980 at Intevep, the PDVSA Research and Development arm. Here, he gained experience in the development of catalysts and process technology. In 1987, he was appointed head of the catalysis section and for four years, beginning in 1990, he managed the refining processes development department at PDVSA Intevep.
In 1995, he was named leader of the technology management corporate group, a part of the PDVSA strategic planning coordination. In 1995, he was appointed manager of the PDVSA-Intevep planning function and developed strategic plans for the production of gasoline types with low sulfur content and other technology business plans related to heavy oil conversion and catalysts development.
From March 2000 to December 2002, he held the position of deputy manager of the refining and petrochemicals general division and also served as the designated team manager of new business developments.
In December 2002, he became managing director of refining at PDVSA Oriente, in Puerto La Cruz, Venezuela, with responsibility for all refinery operations. He also led the restoration of refining and transportation operations for crude oil and fuels in eastern Venezuela following the 2002 interruption.
In July 2003, he was appointed director of Petróleos de Venezuela and general manager of exploration and production in Eastern Venezuela. Beginning February 2004, he served as a director with the oversight of trade and supply, maintaining his responsibilities as president of the PDVSA Gas and Bitor subsidiaries.
From March 2005 until July 2006, he was managing director of PDVSA-UK in London. On his return to Venezuela, he worked as advisor to PDVSA America and in February 2007, he was appointed managing director of PDVSA Ecuador. In August of that year, he was appointed executive director of PDVSA America, with responsibility for all activities and projects in South America, in support of bilateral energy security treaties and joint ventures with state enterprises in the energy sector.
As part of his most recent duties as a Petróleos de Venezuela, S.A. (PDVSA) executive, Martínez has been executive director of PDVSA America, and was appointed managing director of PDVSA Argentina on May 30, 2011. He held this position until his appointment to CITGO on May 23, 2013.
Other accolades for Martínez include membership in the New York Academy of Sciences (1994) for his contributions to the study of catalysts in hydro treatment and catalytic cracking and several awards for research undertaken in the field of process technologies and catalysts. He also holds more than 50 international patents and papers in his field of work.
Dr. Darío Merchán
Vice President, Government and Public Affairs
Dr. Darío Merchán joined CITGO parent company Petróleos de Venezuela, S. A. (PDVSA) in 2003 as a member of the Health Services Restructuring Committee. Since then, he has held positions of increasing responsibility with the most recent ones being Executive Director of Human Resources, Executive Director of Health, and president of PDVSA affiliate PDV Servicios de Salud. In August 2011, he was appointed President of the Houston-based Simón Bolívar Foundation, and in February 2012, he became Vice President of Government and Public Affairs at CITGO.
Dr. Merchán holds a Doctor of Medicine degree from Universidad de Los Andes in Mérida, Venezuela (1988). Additionally, he holds specializations in Internal Medicine, also from Universidad de Los Andes (1993), and Oncology (1996) and Public Health (1998), both from Universidad Central de Venezuela in Caracas. In addition to his broad PDVSA experience, he has held a variety of other public service positions in Venezuela, has served on the boards of several organizations and was Venezuelan Deputy Minister of Health in 2004.
Vice President Finance
Maritza Villanueva joined CITGO in 2003 from CITGO parent company Petróleos de Venezuela, S.A. (PDVSA), where she held several positions of financial responsibility including functional manager of treasury and manager of financial operations. She has more than 20 years of financial management experience in the energy business. Villanueva became CITGO Treasurer in June 2006 with responsibilities including cash management activities, debt negotiations and debt compliance reporting. And in December 2011, she became Vice President Finance.
Villanueva holds a bachelor’s degree in public accounting from Universidad Católica Andres Bello in Caracas, Venezuela and a master’s degree in administrative sciences from Universidad de Oriente in Puerto La Cruz, Venezuela.
Richard López became CITGO Corporate Treasurer on December 1, 2012.
Richard has extensive refining industry experience. He specializes in structuring finance and financial planning. Richard joins us from Petróleos de Venezuela, S.A. (PDVSA). He started his career in the oil industry in Venezuela with Lagoven (PDVSA) in 1981. He held several positions in the finance department including an assignment to the Amuay refinery from 1993-1996.
Prior to joining CITGO, Richard held the position of Director of Financial Planning and Joint Venture Coordinator for Hovensa in St. Croix, Virgin Islands. In this role, he was responsible for the planning and coordination of operational and executive committees (PDVSA and Hess Corp.).
He holds a bachelor of science in economics from Universidad Central de Venezuela in Caracas, Venezuela, and a masters in international management from the Thunderbird School of Global Management in Glendale, Arizona.
Vice President Supply and Marketing
Gustavo Velásquez, joined CITGO in 1997, where he served in various management positions, including manager crude supply and refining coordination and general manager crude supply, with responsibilities over the areas of crude oil and feedstocks supply, industrial products, and marine transportation and logistics, before becoming vice president supply and marketing in 2008. He started his career in the oil refining industry with PDVSA in 1978 and joined UNO-VEN in 1994 prior to coming to CITGO.
He has a bachelor’s degree in chemical engineering from Universidad Simón Bolívar in Caracas.
Vice President, Refining
Eduardo Assef started his career in the oil refining industry in Venezuela in 1985 with PDVSA.
Assef holds a bachelor’s degree in mechanical engineering from Universidad de Carabobo (Venezuela) and received his master’s degree in oil refining, gas and petrochemicals with the French Petroleum Institute and the Universidad Metropolitana.
At PDVSA, Assef held several positions of increasing responsibility in the areas of project, maintenance, process engineering and operations. In 1999 he was transferred to CITGO’s Corpus Christi Refinery, where he held positions in the technical and operational areas. In October 2004, he was appointed general manager, operations and maintenance at the Corpus Christi Refinery. In April 2006, he became vice president and general manager, Corpus Christi Refinery. He was appointed vice president and general manager, Lake Charles Manufacturing Complex in November 2008. And in December 2011, he was appointed Vice President Refining.
Vice President and General Manager, Lake Charles Manufacturing Complex
Tomeu Vadell was named Vice President of the CITGO Lake Charles Refinery on November 5, 2012.
Tomeu has over thirty (30) years of professional experience in the refining and petrochemical industry. During his thirteen-year tenure at the CITGO Lake Charles Refinery, Tomeu has occupied several positions in the technical and operations departments, including Area Operations Manager; Strategic Planning and Capital Projects Manager, Major Projects Manager, and, most recently, General Manager of Engineering and Technical Services.
Before moving to Lake Charles, Tomeu worked for PDVSA (Petróleos de Venezuela) in Puerto La Cruz and El Palito refineries, occupying positions related to engineering and capital projects.
He holds a bachelor of science in mechanical engineering from Universidad Metropolitana in Caracas, Venezuela and a master’s degree in industrial and management engineering from Rensselaer Polytechnic Institute in Troy, New York.
Arthur G. “Sonny” Loudon
Vice President and General Manager, Corpus Christi Refinery
Arthur G. “Sonny” Loudon earned a BS in Chemical Engineering from Brigham Young University, in Provo, Utah, in 1981, and has been with CITGO since 2000. He has held a variety of positions in process design, process technical support and operations management.
Sonny started his career with Conoco at their Process Design Center, in Ponca City, Okla., where he held various engineering and operations positions in the Vista, Lake Charles, La. Manufacturing facilities. Sonny also held various engineering, operations, and environmental positions at Pennzoil manufacturing sites in Roosevelt, Utah and Shreveport, La. and in their corporate design office in Houston.
Vice President and General Manager, Lemont Refinery
Jim Cristman joined CITGO in 1980 and held various positions at the Lemont refinery, including operations manager and operations central services manager, before becoming vice president and general manager in 2008. Prior to joining CITGO, he served in various operations positions at UNO-VEN, including training manager and manager of crude processing. He also served as a member of the executive committee for the Needle Coker Company from 1993 to 1999.
Vice President Legal Affairs
Dr. Orestes Parilli was appointed Vice President Legal Affairs for CITGO on October 1, 2012.
Since 1978, Dr. Parilli’s career has had a remarkable emphasis in the areas of hydrocarbons, international business, projects and negotiations. He started as Manager of Legal Affairs in several operational areas including Production and Refining within PDVSA. He has also served as Manager of National and International Legal Affairs in the largest PDVSA affiliates, as General Legal Counsel, as PDVSA General Manager of International Legal Affairs, and most recently as Senior Advisor to PDVSA.
Dr. Parilli has also practiced law in the private sector, founding his first practice in 1975. He has served as Senior Partner in the areas of development and counsel with four different private firms.
Dr. Parilli graduated in Law from the Universidad Central de Venezuela (UCV).
Dean M. Hasseman
Hasseman holds a juris doctor degree from the University of Virginia School of Law, a bachelor's degree in political science from Northeastern University in Boston, Mass., and a certificate from The Executive Program from the Darden Graduate School of Business at the University of Virginia. He joined CITGO Petroleum Corporation in 1991 as senior corporate counsel after holding positions in the oil and gas industry including senior attorney with Sun Company, Inc. and general counsel with Williams Pipe Line Co. He is admitted to practice law in Texas, Oklahoma, and Pennsylvania. In 2010, Mr. Hasseman was given the additional duties of Chief Compliance Officer.
As General Auditor, Wladimir Noriega leads CITGO's audit group in directing a program of company audits to evaluate operating, administrative and financial controls and to test the adequacy of operating and accounting systems.
Noriega is a Certified Internal Auditor (Institute of Internal Auditors) with more than 30 years of audit experience. After obtaining a bachelor's degree in business and a master's degree in business administration from Emporia State University in Kansas, Noriega began his audit career as a financial auditor for the Comptroller General's Office in Caracas, Venezuela.
He later joined PDVSA affiliate Maraven serving as financial administrative auditor, internal audit supervisor and internal audit manager. He also served PDVSA affiliate Bariven as financial administrative resident auditor and held the position of international business audit manager for PDVSA until joining CITGO in 2003.
John Butts joined CITGO in 1991, having previously worked for Champlin Refining and Chemicals Inc. and Champlin Petroleum (subsidiaries of Union Pacific Corporation). He has served in numerous capacities within CITGO, including feedstock accounting manager, bank operations manager and manager of general accounting, prior to assuming his present position. Butts holds a bachelor's degree in accounting from Phillips University in Enid, Okla., and completed the requirement for CPA certification in the State of Oklahoma in 1981. Mr. Butts has a total of 34 years of experience working in the energy industry in the areas of accounting and finance.