Question: How many employees did the oilfield services company which has B. Clark Burchfiel as a professor have? 

Context articles: TAM International
Norris Production Solutions
B. Clark Burchfiel
TGT Oil and Gas Services
Jean Riboud
Bumi Armada
Schlumberger
Bill Allen (corporate CEO)
Key Energy Services
Superior Energy Services

TAM International, Inc. is a privately held oilfield services company with headquarters in Houston, Texas.
 TAM manufactures products and provides services used in drilling and completions, well intervention, unconventional resources, and reservoir optimization.
 L. Bentley Sanford is the President and CEO.
Dover Artificial Lift (formerly Norris Production Solutions) is an oilfield services company headquartered in The Woodlands, Texas.
 The company provides products and services for artificial lift during production of petroleum and natural gas.
 Dover Artificial Lift is a member of Dover Corporation.
Burrell Clark Burchfiel (born March 21, 1934) is an American structural geologist.
 Born in Stockton, California, he earned his Ph.D. in 1961 at Yale University.
 His first academic appointment was to the Geology department at Rice University.
 He is the Schlumberger Professor of Geology at MIT.
 Research interests: Origin, development, and structural evolution of the continental crust.
 His current work involves study of the geological history and evolution of the Tibetan plateau.
TGT Oilfield Services (TGT Oilfield Services) is an international oilfield service company specialising in production logging, hydrocarbon reservoir monitoring and geohydrodynamic modelling.
 The company is headquartered in Dubai (UAE) and has regional offices in more than fifteen countries including United States, Canada, Russia, Kazakhstan, Nigeria, Malaysia, Great Britain, Indonesia, Oman, Kuwait and Saudi Arabia.
 In Russia, TGT has its Technology Centre in Kazan and other offices in Usinsk and at the Skolkovo Technopark in Moscow.
Jean Riboud (15 November 1919 – 20 October 1985) was a French socialist, corporate executive and the chairman of Schlumberger, the largest oilfield services company in the world.
 He was a member of the French Resistance during World War II and suffered incarceration in Buchenwald concentration camp of the Nazis.
 His contributions were reported in making Schlumberger into the market leader in oilfield services sector.
 The Government of India awarded him the third highest civilian honour of the Padma Bhushan, in 1986, for his contributions to society.
Bumi Armada Berhad is an oilfield services company which provides marine transportation, engineering and maintenance services to the offshore oil and gas industry.
 It is based in Kuala Lumpur, Malaysia, and has operations in Southeast Asia, South Asia, Central Africa, South America, Australia and the Caspian Sea region.
 It is the world's fifth largest floating production storage and offloading (FPSO) provider with six vessels.
Schlumberger Limited (] ) is the world's largest oilfield services company.
 Schlumberger employs approximately 100,000 people
Bill Allen (04/06/37) is the former CEO of the Alaska oilfield services company VECO Corporation.
 VECO was an Alaska-based oil pipeline service and construction company founded by Wayne Veltri (VECO is short for Veltri Co).
 Bill Allen was born in New Mexico and at the age of 16 left for the oil fields of Alaska to become a welder to help support his family.
 VECO began as a one truck welding and repair operation that grew to become a major player in the Alaskan and worldwide oil industries' support services business.
 He built a for-profit prison in Barbados as well.
 VECO also was a worldwide player in the oil industry, having divisions in many major oil markets, including the Sudan, Russia, Mexico, Venezuela and Syria.
 VECO had a major impact on the economy of Alaska and employed over 5,000 people worldwide.
Key Energy Services is an American oilfield services company.
Superior Energy Services, Inc. is an oilfield services company.
 In 2014 it ranked 534 on the Fortune 1000.