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Schlumberger Limited
IndustryOilfield services and equipment
Founded1926; 97 years ago (1926) (as Electric Prospecting Company)
Paris, France
FoundersConrad Schlumberger
Marcel Schlumberger
HeadquartersPrincipal executive offices:
Paris, France
Houston, Texas, U.S.
London, UK
The Hague, Netherlands;
Legal domicile:
Willemstad, Curaçao, Kingdom of the Netherlands
Area served
Key people
Olivier Le Peuch (CEO)
RevenueDecrease US$23.601 billion (2020)[1]
Decrease US$1.656 billion (2020)[1]
Decrease US$-10.518 billion (2020)[1]
Total assetsDecrease US$42.434 billion (2020)[1]
Total equityDecrease US$12.489 billion (2020)[1]
Number of employees
86,000 (2020)

Schlumberger Limited (French: [ʃlum.bɛʁˈʒe, ʃlœ̃-]), doing business as SLB, is an oilfield services company.[2][3] Schlumberger has four principal executive offices located in Paris, Houston, London, and The Hague.[4]

Schlumberger is the world's largest offshore drilling company. It is the biggest offshore drilling contractor (in terms of revenue) in the world.[5]

Schlumberger is incorporated in Willemstad, Curaçao as Schlumberger N.V.[6] and trades on the New York Stock Exchange, Euronext Paris, the London Stock Exchange and SIX Swiss Exchange.[7] Schlumberger is a Fortune Global 500 company, ranked 287 in 2016,[8] and also listed in Forbes Global 2000, ranked 349 in 2022.[9]


This Houston building, as of 2015, houses the Schlumberger U.S. executive offices
1938 Schlumberger Corporation building
Schlumberger complex in Sugar Land, Texas
Logo used to October 2022.

Schlumberger was founded in 1926 in Paris as the Electric Prospecting Company (French: Société de prospection électrique) by two brothers Conrad and Marcel Schlumberger from Alsace.[10] Schlumberger supplies the petroleum industry with services such as seismic data processing, formation evaluation, well testing and directional drilling, well cementing and stimulation, artificial lift, well completions, flow assurance and consulting, and software and information management. The company is also involved in the groundwater extraction[11] and carbon capture and storage industries.[12]

The Schlumberger brothers had experience conducting geophysical surveys in countries such as Romania, Canada, Serbia, South Africa, the Democratic Republic of the Congo,[13] and the United States. The new company sold electrical-measurement mapping services, and recorded the first-ever electrical resistivity well log in Merkwiller-Pechelbronn, France, in 1927.[14] The company quickly expanded, logging its first well in the U.S. in 1929 in Kern County, California. In 1934, the Schlumberger Well Surveying Corporation was founded in Houston,[15] later evolving into Schlumberger Well Services, and finally Schlumberger Wireline and Testing. Schlumberger invested heavily in research, inaugurating the Schlumberger-Doll Research Center in Ridgefield, Connecticut in 1948, contributing to the development of a number of new logging tools. In 1956, Schlumberger Limited was incorporated as a holding company for all Schlumberger Limited businesses, which by now included American testing and production company Johnston Testers.[citation needed]

Over the years, Schlumberger continued to expand its operations and acquisitions. In 1960, Dowell Schlumberger (50% Schlumberger, 50% Dow Chemical), which specialized in pumping services for the oil industry, was formed. On February 2, 1962, Schlumberger Limited became listed on the New York Stock Exchange.[16][17] That same year, Schlumberger purchased Daystrom, an electronic instruments manufacturer in South Boston, Virginia which was making furniture by the time the division was sold to Sperry & Hutchinson in 1971.[18] Schlumberger purchased 50% of Forex in 1964 and merged it with 50% of Languedocienne to create the Neptune Drilling Company. The first computerized reservoir analysis, SARABAND, was introduced in 1970. The remaining 50% of Forex was acquired the following year; Neptune was renamed Forex Neptune Drilling Company. In 1979, Fairchild Camera and Instrument (including Fairchild Semiconductor) became a subsidiary of Schlumberger Limited.[19]

In 1981, Schlumberger established the first international data links with e-mail. In 1983, Schlumberger opened its Cambridge Research Center in Cambridge, England.[20]

In 1984, the SEDCO drilling rig company and half of Dowell of North America were acquired, resulting in the creation of the Anadrill drilling segment, a combination of Dowell and The Analysts' drilling segments. Forex Neptune was merged with SEDCO to create the Sedco Forex Drilling Company the following year, when Schlumberger purchased Merlin and 50% of GECO.[citation needed]

In 1987, Schlumberger completed its purchases of Neptune (North America), Bosco and Cori (Italy), and Allmess (Germany). That same year, National Semiconductor acquired Fairchild Semiconductor from Schlumberger for $122 million.[21]

In 1991, Schlumberger acquired PRAKLA-SEISMOS, and pioneered the use of geosteering to plan the drill path in horizontal wells.[citation needed]

In 1992, Schlumberger acquired software company GeoQuest Systems. With the purchase came the conversion of SINet to TCP/IP and thus internet capable. In the 1990s Schlumberger bought out the petroleum division, AEG meter, and ECLIPSE reservoir study team Intera Technologies Corp. A joint venture between Schlumberger and Cable & Wireless resulted with the creation of Omnes, which then handled all of the company's internal IT business. Oilphase and Camco International were also purchased.[citation needed]

In 1999, Schlumberger and Smith International created a joint venture, M-I L.L.C., the world's largest drilling fluids (mud) company. The company consists of 60% Smith International, and 40% by Schlumberger. Since the joint venture was prohibited by a 1994 antitrust consent decree barring Smith from selling or combining their fluids business with certain other companies, including Schlumberger, the U.S. District Court in Washington, D.C. found Smith International Inc. and Schlumberger Ltd. guilty of criminal contempt and fined each company $750,000 and placed each company on five years probation. Both companies also agreed to pay a total of $13.1 million, representing a full disgorgement of all of the joint venture's profits during the time the companies were in contempt.[22]

In 2000, the Geco-Prakla division was merged with Western Geophysical to create the seismic data acquisition and processing contracting company WesternGeco, of which Schlumberger held a 70% stake, the remaining 30% belonging to competitor Baker Hughes. Sedco Forex was spun off, and merged with Transocean Drilling company in 2000.[citation needed]

In 2001, Schlumberger acquired the IT consultancy company Sema plc for $5.2 billion. The company was an Athens 2004 Summer Olympics partner, but the venture into IT consultancy did not pay off, and divestiture of Sema to Atos Origin was completed that year for $1.5 billion. The cards division was divested through an IPO to form Axalto, which later merged with Gemplus to form Gemalto, and the Messaging Solutions unit was spun off and merged with Taral Networks to form Airwide Solutions. In 2003, the Automated Test Equipment group, part of the 1979 Fairchild Semiconductor acquisition, was spun off to NPTest Holding, which later sold it to Credence.[citation needed]

In 2004, Schlumberger Business Consulting was launched and a decade later was acquired by Accenture.[23]

In 2005, Schlumberger purchased Waterloo Hydrogeologic,[24][unreliable source?] which was followed by several other groundwater industry related companies, such as Westbay Instruments, and Van Essen Instruments. Also that year, Schlumberger relocated its U.S. corporate offices from New York to Houston.[25]

In 2006, Schlumberger purchased the remaining 30% of WesternGeco from Baker Hughes for US$2.4 billion.[26] Also that year, the Schlumberger-Doll Research Center was relocated to a newly built research facility in Cambridge, Massachusetts to replace the Ridgefield, Connecticut research center. The facility joins the other research centers operated by the company in Cambridge, England; Moscow, Russia; Stavanger, Norway; and Dhahran, Saudi Arabia.[27] In March 2022, Schlumberger stopped investing in its projects in Russia because of International sanctions during the Russo-Ukrainian War.[28]

In 2009, Schlumberger acquired the shares of Techsia SA, a supplier of petrophysical software based in Montpellier, France. Techsia is well known in the industry for its flagship Techlog© product. The Montpellier-based Techsia center becomes then the Schlumberger Petrophysics Software Center of Excellence for the development of state-of-the-art solutions for the oil and gas exploration and production industry

In 2010, the acquisition of Smith International in an all-stock deal valued at $11.3 billion was announced. The sale price is 45.84-a-share price was 37.5 percent higher than Smith closing price on 18 February 2010. The deal is the biggest acquisition in Schlumberger history.[29] The merger was completed on August 27, 2010.[30] Also announced in 2010 were Schlumberger plans to acquire Geoservices, a French-based company specializing in energy services, in a deal valued at $1.1 billion, including debt.[31]

In 2014, Schlumberger announced the purchase of the remaining shares of SES Holdings Limited ("Saxon"), a Calgary-based provider of international land drilling services, from First Reserve and certain members of Saxon management. The transaction is subject to customary closing conditions, including the receipt of regulatory approvals. Schlumberger had a minority share in Saxon previously.[32]

In 2015, Schlumberger was indicted by the US Department of Justice for sanction violations of conducting business in Iran and Sudan; the company was fined $233 million, amounting to the largest fine for sanctions to date.[33]

In 2015, due to a downturn in the global oil and gas industry, Schlumberger announced 21,000 layoffs accounting for 15% of the company's total workforce.[34]

In 2015, Schlumberger agreed to acquire oilfield equipment manufacturer Cameron International for $14.8 billion.[35]

In 2018, Schlumberger announced that WesternGeco would be exiting the seismic data acquisition business, both onshore and offshore, while retaining its multiclient data processing and interpretation segments. This decision followed the bankruptcy filings of several competitors in the seismic services sector.[36]

In 2020, Schlumberger cut more than 21,000 jobs during the global COVID-19 pandemic.[37]

In 2021, Schlumberger New Energy announced the signature of pilot project agreements between the French state, Genvia and critical-industry leaders on the pathway to net zero in the cement and steel industries. Through these agreements, the goal is to scale up the next generation of electrolyzer technology, developed over the last two decades, to produce clean hydrogen without CO2 emissions, accelerating the decarbonization of multiple industrial sectors.

In 2022, Schlumberger completed a corporate rebranding to be known as SLB. According to media statements, the company's CEO said the corporate rebranding is not a shift away from fossil fuels.[38]

Corporate affairs[edit]


The company has offices in multiple cities and regions in France: Abbeville,[39] Béziers,[40] Clamart,[41] Montpellier,[42] Pau [43] and Paris.[44][45]

Such sites and entities are as well at the forefront of the SLB New Energy strategy and development. (example: Geothermal with Celsius Energy[46] and Hydrogen with Genvia[47])

United States[edit]

Schlumberger maintains a 33-acre (13 ha) campus at the northeast corner of U.S. Highway 90A and Gillingham Lane in Sugar Land, Texas; as of 2017 Schlumberger is the third largest employer in the city. In 2015, Schlumberger announced that it was moving its U.S. corporate headquarters to the Sugar Land facility from its Houston office building. The company plans to build new buildings with a scheduled completion time of late 2017. They include a total of 250,000 square feet (23,000 m2) of Class A office space and an "amenities" building with 100,000 square feet (9,300 m2) of space.[48]

In the 1930s, the North American headquarters were established in Houston. In the 1970s, the company's top executives in North America were relocated to New York City. By 2006, the head office had 50 executives and support staff. By that year the company was moving that office to a building near the Houston Galleria.[49]

The company moved its Houston-area offices from 5000 Gulf Freeway in Houston to the Sugar Land campus in 1995.[50][51][52]


In 2009, Newsweek released their "Green Rankings",[53] a ranking of the 500 largest corporations on track records on a number of environmental issues. Schlumberger was ranked 118th out of 500 overall, and third out of 31 in their industry. Newsweek remarked that to mitigate global warming Schlumberger has invested in carbon sequestration which involves long-term storage of CO2 and that the company's seismic survey ships are 20% to 25% more fuel-efficient than those of other seismic contractors from using fuels that emit less pollution and towing equipment that creates less drag on the vessels.[54]


Radioactive sources[edit]

In 2006, a radioactive canister imported by Schlumberger was recovered in the Western Australian outback desert.[55] The canister had been lost by the company's transport partner, when the improperly secured container fell off the trailer on which it was being transported.[56]

In 2010, the Aberdeen Sheriff court fined Schlumberger Oilfield UK £300,000 for losing a radioactive source on the rig floor on the Ensco 101 mobile drilling rig in the North Sea for 4 hours.[57]


In 2009, the Pennsylvania Department of Environmental Protection fined Chesapeake Appalachia LLC and Schlumberger Technology Corp. more than $15,500 each for a hydrochloric acid spill in February 2009 at Chesapeake's Chancellor natural gas well site in Asylum Township, Bradford County, Pennsylvania. Officials said the leak did not contaminate groundwater.[58]

PCB contamination[edit]

In 2006, as the current owner of a facility in Pickens, South Carolina, Schlumberger agreed to pay $11.8 million to federal and state agencies for a problem caused by the previous owner, Sangamo-Weston, a capacitor manufacturing plant.[59] The cause of the problem was from polychlorinated biphenyls (PCB) released into the environment by Sangamo-Weston from 1955 to 1987. According to the Justice Department's Environment and Natural Resources Division, an additional agreement by Schlumberger to purchase and remove dams will directly improve the Twelvemile Creek, South Carolina ecosystem and provide significant environmental benefits for the affected communities.[60]

Deepwater Horizon[edit]

In 2010, Schlumberger was contracted to perform wireline logging on the Deepwater Horizon oil rig in the Gulf of Mexico. On the day of the explosion, the Schlumberger crew was supposed to perform a cement evaluation test, but the test was cancelled and the crew was released by BP to leave the rig on the same day.[61][62] The cost-cutting decision to cancel the test is dramatized in the subsequent film by Peter Berg.

Business with Iran and Sudan[edit]

In 2015, Schlumberger pled guilty to violating U.S. sanctions related to Iran and Sudan and agreed to pay a $237 million penalty.[63]

Sexual harassment[edit]

In 2020, a class action lawsuit was filed against Schlumberger, alleging a culture of sexual harassment, discrimination, and retaliation.[64] According to the company's pay-gap report for 2018, women composed a mere 5.4% of field roles and 16.2% of roles in the full company. The lawsuit alleges that males regularly documented female co-workers and flaunted them on public forums. Male colleagues would also encourage other men to break into the plaintiff's room at night and stonewall her if she did not consent to sexual activity. The lawsuit also outlines instances of "sexist and hostile comments," and one instance in which the plaintiff was groped. Women who complain to HR are told it's all just "oil field talk" and are subsequently ignored. When the plaintiff kept complaining, Schlumberger allegedly terminated the plaintiff. Women who spoke with the Texas Observer describe a culture of silence, where women stay silent for fear of being fired in the high turnover company.[65]


In October 2022, it was reported that some of Schlumberger's more than 9,000 Russian employees based in Russia received military draft notices through the company. Human rights groups such as Business & Human Rights Resource Centre are watching how the company responds to the concerns.[66] About a week later, the company said it was evaluating unspecified options for its thousands of Russian employees.[67] According to a list maintained by the Chief Executive Leadership Institute at Yale University which tracks company responses about operating in Russia, Schlumberger is noted as "buying time" while it continues to carry out the bulk of its business in the country.[68]

See also[edit]


  1. ^ a b c d e "Schlumberger Limited (SLB)". Yahoo! Finance.
  2. ^ Wethe, David (January 20, 2012). "Schlumberger Fourth-Quarter Profit Rises as Drilling Booms". Bloomberg News.
  3. ^ "Schlumberger to cut 9,000 jobs on oil-price plunge". Reuters. January 15, 2015 – via CNBC.
  4. ^ "Bloomberg Business Week". Retrieved July 14, 2010.
  5. ^ "Top 10 Biggest Offshore Drilling Companies in the World". May 9, 2022. Retrieved January 26, 2023.
  6. ^ "Schlumberger N.V. - Company Information".
  7. ^ "10-K". Retrieved March 26, 2015.
  8. ^ "Schlumberger (SLB) Stock Price, Financials and News Global 500". Fortune. Retrieved September 9, 2016.
  9. ^ "Schlumberger on the Forbes Global 2000 List". Forbes. Retrieved September 9, 2016.
  10. ^ Oristaglio & Dorozynski 2007, p. 39.
  11. ^ "Schlumberger Water Services." Schlumberger Web site. Retrieved on January 30, 2011.
  12. ^ "Schlumberger Carbon Services." Schlumberger Web site. Retrieved on January 30, 2011.
  13. ^ Oristaglio & Dorozynski 2007, p. 67.
  14. ^ Oristaglio & Dorozynski 2007, p. 58.
  15. ^ Oristaglio & Dorozynski 2007, p. 143.
  16. ^ "Listings Directory Schlumberger Limited." NYSE web site. Retrieved on September 02, 2013.
  17. ^ Oristaglio & Dorozynski 2007, p. 284.
  18. ^ "History of LADD Furniture, Inc". Retrieved November 1, 2012.
  19. ^ Staff (October 2, 2009). "The Schlumberger-Fairchild Cock-Up". Electronics Weekly. Retrieved November 8, 2022.
  20. ^ "Schlumberger Cambridge Research Center". AJ Buildings Library. Retrieved December 14, 2021.
  21. ^ "History, Schlumberger". Slb. Archived from the original on February 6, 2010. Retrieved January 27, 2010.
  22. ^ "Companies Fined $1.5 Million". December 9, 1999.
  23. ^ "World Oil". August 18, 2015.
  24. ^[unreliable source?] Archived September 29, 2007, at the Wayback Machine
  25. ^ "Houston Chronicle". October 26, 2005.
  26. ^ Gold, Russell (April 22, 2006). "Schlumberger Buys 30% Venture Stake From Baker Hughes". The Wall Street Journal. Retrieved March 19, 2015.
  27. ^ "Schlumberger Research." Schlumberger. Retrieved on January 30, 2011.
  28. ^ "Нефтесервисная корпорация Schlumberger прекращает инвестиции в свою деятельность в России" [Oilfield services corporation Schlumberger stops investing in its activities in Russia] (in Russian). TASS. March 19, 2022.
  29. ^ "Schlumberger to Acquire Smith for About $11 Billion (Update3)." BusinessWeek. February 21, 2010. Retrieved on February 23, 2010.
  30. ^ "Yahoo Finance - Schlumberger Completes Merger with Smith International". Retrieved September 20, 2010.
  31. ^ Schlumberger to buy Geoservices for $1.1 billion Retrieved from MarketWatch 25 February 2010
  32. ^ "Schlumberger Purchases Remaining Shares of Saxon". Retrieved August 28, 2015.
  33. ^ Hong, Nicole (March 25, 2015). "Schlumberger Unit to Plead Guilty to Violating Iran, Sudan Sanctions". WSJ. Retrieved August 28, 2015.
  34. ^ Edward C. Baig, USA TODAY (April 17, 2015). "More Big Oil layoffs: Schlumberger axes 11K jobs". USA Today. Retrieved August 28, 2015.
  35. ^ "Schlumberger to Buy Cameron in $14.8 Billion Oil Services Deal". Bloomberg. August 26, 2015. Retrieved August 27, 2015.
  36. ^ Addison, Velda (January 19, 2018). "Schlumberger To Exit Land, Marine Seismic Acquisition Business". Exploration & Production. Retrieved February 23, 2018.
  37. ^ Addison, Velda (July 24, 2020). "Schlumberger layoffs: Company cuts 21K jobs amid COVID-19 pandemic oil rout". Exploration & Production. Retrieved May 21, 2022.
  38. ^ Hampton, Liz (October 24, 2022). "Oil giant Schlumberger rebrands itself as SLB for low-carbon future". Reuters.
  39. ^ "SCHLUMBERGER VECTOR SAS (ABBEVILLE) Chiffre d'affaires, résultat, bilans sur SOCIETE.COM - 428112320". Retrieved December 19, 2022.
  40. ^ "Etablissement SCHLUMBERGER SA à BEZIERS (34500) sur SOCIETE.COM (54206212000259)". Retrieved December 19, 2022.
  41. ^ "Etablissement ETUDES ET PRODUCTIONS SCHLUMBERGER à CLAMART (92140) sur SOCIETE.COM (69202147000020)". Retrieved December 19, 2022.
  42. ^ "Etablissement SERVICES PETROLIERS SCHLUMBERGER à MONTPELLIER (34000) sur SOCIETE.COM (54206611300334)". Retrieved December 19, 2022.
  43. ^ "Etablissement SERVICES PETROLIERS SCHLUMBERGER à PAU (64000) sur SOCIETE.COM (54206611300250)". Retrieved December 19, 2022.
  44. ^ "Europe, C.I.S. & Africa Area ." Schlumberger. Retrieved on October 25, 2015. "Services Techniques Schlumberger Le Palatin 1, 1 Cour du Triangle 92936 La Defense, Cedex France"
  45. ^ "Palatin I, II et III (Le)." Établissement public de gestion du quartier d'affaires de la Defense (Defacto). Retrieved on 26 October 2015. "Adresse : 30, Rue de Valmy - 92800 Puteaux"
  46. ^ "About Celsius Energy Geothermal Building Heating Solutions". Celsius Energy. Retrieved December 19, 2022.
  47. ^ "Genvia, a Schlumberger Joint Venture in Clean Hydrogen Technology, Signs Pilot Project Agreements in Steel and Cement, Supporting the Decarbonization of Critical Industry Sectors". Retrieved December 19, 2022.
  48. ^ Mulvaney, Erin. "Schlumberger plans to relocate national headquarters to Sugar Land" (Archive). Houston Chronicle. October 5, 2015. Retrieved on October 24, 2015.
  49. ^ Clanton, Brett. "ENERGY / Growth in the oil patch translates into good times for oil-field-services firms like Schlumberger - and for Houston / The best of times means more jobs" (Archive). Houston Chronicle. Friday September 29, 2006. Business 1. Retrieved on January 13, 2009.
  50. ^ Sarnoff, Nancy. "Burger King sniffing for new home / Houston said to be in running for headquarters' possible relocation" (Archive). Houston Chronicle. Sunday February 3, 2005. Business 3. Retrieved on January 13, 2009.
  51. ^ "Schlumberger to move U.S. headquarters to Houston". Houston Business Journal. Wednesday October 26, 2005. Retrieved on January 13, 2009.
  52. ^ "North America (NAM) Contacts Archived 2009-02-04 at the Wayback Machine". Schlumberger. Retrieved on January 13, 2009.
  53. ^ McGinn, Daniel (September 20, 2009). "Newsweek Greenest Big Companies in America ??? The 2009 List". Newsweek. Retrieved July 21, 2010.
  54. ^ "Newsweek ???Green Ranking- Schlumberger". Retrieved July 21, 2010.
  55. ^ "Radioactive canister found on road | Perth Now". October 14, 2014. Archived from the original on October 14, 2014. Retrieved March 10, 2022.
  56. ^ Thomas Hunter writes (January 17, 2007). "Found: WA???s missing radioactive canister". Crikey. Retrieved January 27, 2010.
  57. ^ "Press and Journal - Article - Radioactive device put oil rig crew in danger". May 23, 2012. Archived from the original on May 23, 2012. Retrieved March 10, 2022.
  58. ^ "DEP fines Chesapeake Appalachia, Schlumberger for acid spill in Bradford County". The Times-Tribune (Scranton). December 8, 2009. Retrieved December 22, 2010.
  59. ^ "#06-046: 01-30-06 Company to Pay $11.8 Million in Compensation for PCB-Damaged Fishery and Habitat". Retrieved March 10, 2022.
  60. ^ "Company To Pay $11.8 Million". Environmental Protection. February 1, 2006. Retrieved July 22, 2010.
  61. ^ Reddall, Braden (May 19, 2010). "Schlumberger says its crew left Horizon day of fire-Deep Water Horizon Accident- Schlumberger". Reuters. Retrieved May 15, 2010.
  62. ^[bare URL PDF]
  63. ^ Edwards, Julia (March 25, 2015). "Schlumberger pleads guilty to violating U.S. sanctions on Iran, Sudan". Reuters. Retrieved February 25, 2022.
  64. ^ Pulsinelli, Olivia (June 23, 2020). "Schlumberger faces $100M class action lawsuit alleging discrimination against women". Houston Business Journal. Retrieved February 24, 2022.
  65. ^ Sundaram, Arya (December 14, 2020). "The Oil and Gas Industry Still Hasn't Reckoned with #MeToo". The Texas Observer. Retrieved February 24, 2022.
  66. ^ Hampton, LIZ (October 14, 2022). "EXCLUSIVE Schlumberger faces employee backlash in Russia over draft cooperation". Reuters.
  67. ^ Hampton, LIZ (October 20, 2022). "Schlumberger evaluates options for Russia staff as Ukraine war escalates -CEO". Reuters.
  68. ^ Hogg, Ryan (October 15, 2022). "Texas-based oil giant accused of failing to help its Russian workers avoid being conscripted by Putin, report says". Business Insider.

Works cited[edit]

External links[edit]

  • SLB website
  • Business data for Schlumberger: