Schlumberger is an oilfield services company. Schlumberger employs approximately 100,000 people  representing more than 140 nationalities working in more than 120 countries. Schlumberger has four principal executive offices located in Paris, Houston, London, and The Hague. 

Schlumberger is incorporated in Willemstad, Curaçao as Schlumberger N.V. and trades on the New York Stock Exchange, Euronext Paris, the London Stock Exchange and SIX Swiss Exchange. Schlumberger is a Fortune Global 500 company, ranked 287 in 2016, and also listed in Forbes Global 2000, ranked 176 in 2016. 

Schlumberger, the world’s biggest oilfield services company, earned a record full-year revenue of $32.81bn in 2018, a 7.8% increase from its 2017 revenues of $30.44bn.

Its offshore drilling services include extended-reach, deepwater, and high-pressure, high-temperature wells, as well as multilateral and unconventional gas. Schlumberger provided drilling management services for the Epsilon Oilfield in the Aegean Sea, Greece.

It was also involved in the development of oilfields such as the Avouma Field in Gabon and the Bream Area Project, Central North Sea, Norway. 

According to en.wikipedia & offfshore-technology