In 1999 Schlumberger proposed a merger of equals with Schlumberger's offshore subsidiary Sedco Forex. The deal was valued at US$3.2 billion. The new company was renamed Transocean Sedco Forex. (The name was simplified to Transocean in 2003.) Sedco Forex had been formed from a merger of two drilling companies, the Southeast Drilling Company (Sedco), founded in 1947 by Bill Clements and acquired by Schlumberger in 1985 for $1 billion, and French drilling company Forages et Exploitations Pétrolières (Forex) founded in 1942 in German occupied France for drilling in North Africa. Schlumberger first got a foothold in the company in 1959 and then assumed total control in 1964 and renamed it Forex Neptune Drilling Company. The spunoff Houston-based Transocean was part of the S&P 500.
In 2000 Transocean acquired R&B Falcon in a deal valued at $17.7 billion. With the acquisition Transocean gained control of what at the time was the world's largest offshore operation. Among R&B Falcon's assets was the Deepwater Horizon. R&B Falcon was formed in 1997 from the merger of Reading and Bates Exploration, which had been founded in 1970 and headquartered in Tulsa, Oklahoma, and Falcon Drilling, which had been founded in 1988 by Steven A. Webster with a $300,000 investment and headquartered in Houston.
In 2005 Discoverer Spirit set a world record for deepest offshore oil and gas well of 34,189 ft (10,421 m)