Major Contract Drilling Companies
Land-Based
Nabors Industries Ltd. (Largest land-based drilling company in North America, as of 1993)
Nabors is a very successful land drilling contractor as well as one of the largest international land drilling contractors. This company has a fleet of over 500 land drilling rigs that currently operate in most of the significant oil, gas, and geothermal drilling markets in the world. Nabors also provides offshore drilling services.
Patterson-UTI Energy (Second largest land-based drilling company in North America)
This company, based in Texas, supplies onshore contract drilling services to major independent oil and natural gas providers. Patterson-UTI owns 325 land rigs and operates mainly in Texas, New Mexico, Utah, Oklahoma, North Dakota, South Dakota, Wyoming, Montana, Louisiana, and Western Canada.
Ocean Offshore
Transocean Sedco Forex (World's largest offshore drilling company)
This company provides the most versatile fleet of mobile offshore drilling units to help clients find and develop oil and natural gas reserves. Having more than 50 years of experience, Transocean has developed the highest specification of oil rigs and has approximately 21,100 employees that are focused on safety and high quality offshore drilling performance.
Parker Drilling Company
PKD (Parker Drilling Company) contracts out its drilling rigs and equipment to companies exploring for oil and natural gas offshore and, to a lesser extent, on land. Their oil rigs are able to penetrate the earths at depths more than 1000 feet. This company also makes money by contracting out their equipment (depending on the opportunity cost associated with company or second party use) instead of an actual drill team. PKD is one of the two most actively employed international drilling companies in places such as in the Asia Pacific, Latin America, the Middle East, and even in the Caspian Sea.