Chevron Corporation is an American multinational energy corporation predominantly in oil and gas. The second-largest direct descendant of Standard Oil, and originally known as the Standard Oil Company of California, it is headquartered in San Ramon, California, and active in more than 180 countries. Within oil and gas, Chevron is vertical integrated and is involved in hydrocarbon exploration, production, refining, marketing and transport, chemicals manufacturing and sales, and power generation.
Dresser Industries was a multinational corporation headquartered in Dallas, Texas, United States, which provided a wide range of technology, products, and services used for developing energy and natural resources. In 1998, Dresser merged with its main rival Halliburton. Halliburton sold many of former Dresser non "oil patch" divisions, retaining the M W Kellogg Engineering and Construction Company and the Dresser oil-patch products and services that complemented Halliburton's energy and natural resource businesses. In 2001 Halliburton sold five separate, but somewhat related former Dresser non "oil patch" divisions, to an investment banking firm. Those five operations later took the name "Dresser Inc." In October 2010, Dresser Inc., was acquired by General Electric. It is headquartered in Addison, Texas.
Schlumberger Limited, doing business as SLB, is an oilfield services company. As of 2022, it is both the world's largest offshore drilling company and the world's largest offshore drilling contractor by revenue.
Baker Hughes Company, organized in Delaware and headquartered in Houston, is one of the world's largest oil field services companies. The company provides products and services for oil well drilling, formation evaluation, completion, production, and reservoir consulting. It operates in over 120 countries, with research and manufacturing facilities in Australia, Singapore, Malaysia, India, Dubai, Saudi Arabia, Italy, Germany, Norway, Oklahoma, Louisiana and Missouri. From 2017 to 2020, the company was majority owned by General Electric (GE); however, GE no longer owns an economic stake in the company.
Well logging, also known as borehole logging is the practice of making a detailed record of the geologic formations penetrated by a borehole. The log may be based either on visual inspection of samples brought to the surface or on physical measurements made by instruments lowered into the hole. Some types of geophysical well logs can be done during any phase of a well's history: drilling, completing, producing, or abandoning. Well logging is performed in boreholes drilled for the oil and gas, groundwater, mineral and geothermal exploration, as well as part of environmental and geotechnical studies.
Transocean Ltd. is an American company. It is the world's largest offshore drilling contractor based on revenue and is based in Vernier, Switzerland. The company has offices in 20 countries, including Canada, the United States, Norway, United Kingdom, India, Brazil, Singapore, Indonesia, and Malaysia.
China Oilfield Services (COSL) is an oilfield services company. It is a majority owned subsidiary of Chinese state owned company CNOOC Group. It also has a listed sister company in Hong Kong, CNOOC Limited.
NOV Inc., formerly National Oilwell Varco, is an American multinational corporation based in Houston, Texas. It is a worldwide provider of equipment and components used in oil and gas drilling and production operations, oilfield services, and supply chain integration services to the upstream oil and gas industry. The company conducts operations in more than 500 locations across six continents, operating through three reporting segments: Rig Technologies, Wellbore Technologies, and Completion & Production Solutions.
Tesco Corporation was an oilfield services company that provided top drive rental services on a day-rate basis for land and oil platforms as well as casing running. It was headquartered in Spring Branch, Houston. In December 2017, the company was acquired by Nabors Industries.
Valaris Limited is an offshore drilling contractor headquartered in Houston, Texas, and incorporated in the UK. It is the largest offshore drilling and well drilling company in the world, and owns 56 rigs, including 40 offshore jackup rigs, 11 drillships, and 5 semi-submersible platform drilling rigs.
APA Corporation is the holding company for Apache Corporation, an American company engaged in hydrocarbon exploration. It is organized in Delaware and headquartered in Houston. The company is ranked 431st on the Fortune 500.
Weatherford International plc, an American–Irish public limited company, together with its subsidiaries, is a multinational oilfield service company and one of the largest companies in the world in oil services. Weatherford is a company providing equipment and services used in the drilling, evaluation, completion, production, and intervention of oil and natural gas wells. Many of the company's businesses, including those of predecessor companies, have been operating for more than 50 years.
McDermott International, Ltd is a global provider of engineering and construction solutions to the energy industry. Operating in over 54 countries, McDermott has more than 40,000 employees, as well as a diversified fleet of speciality marine construction vessels and fabrication facilities around the world. Incorporated in Bermuda, It is headquartered in the Energy Corridor area of Houston, Texas.
Cameron International Corporation (formerly Cooper Cameron Corporation (CCC) and Cooper Oil Tool, Cameron Iron Works) though now operating under Schlumberger, is a global provider of pressure control, production, processing, and flow control systems as well as project management and aftermarket services for the oil and gas and process industries. Cameron was acquired by Schlumberger (SLB) in 2016, and now operates as 'Cameron, a Schlumberger Company.' At the start of the SLB acquisition in 2015, Cameron employed approximately 23,000 people and delivered $9.8 billion in revenue.
Grant Prideco, Inc. is a supplier of drill pipe and drill stem accessories headquartered in Houston, Texas. Since 2008, it has been a subsidiary of energy services company NOV Inc. Grant Prideco was included on the Fortune magazine top 1000 largest corporations for several years in the mid-2000s and through the 1990s and early 2000s was the world's largest oilfield drill pipe supplier.
Superior Energy Services, Inc. is a C-corporation that operates as a holding company for a portfolio of oilfield rentals and well services brands. The Company restructured in 2021 and is no longer listed on an exchange. Its majority beneficial owners as of March 4, 2022, per the latest filings with the Securities and Exchange Commission, are GoldenTree Asset Management LP and Monarch GP LLC.
Forum Energy Technologies Forum Energy Technologies is a global oilfield products company that provides products and services to the oil and gas, and renewable industries.
GE Oil & Gas was the division of General Electric that owned its investments in the petroleum industry. In July 2017, this division was merged with Baker Hughes.
OneSubsea is a Schlumberger company, headquartered in Houston, Texas, United States. The company is a subsea supplier for the subsea oil and gas market.
According to the United States Energy Information Administration (EIA), Pakistan may have over 9 billion barrels (1.4×109 cubic metres) of petroleum oil and 105 trillion cubic feet (3.0 trillion cubic metres) in natural gas (including shale gas) reserves.
$10.770 billion USD (2008) [1] 
