Transocean Inc., Houston, (NYSE: RIG) has completed its merger with GlobalSantaFe Corp., Houston, (NYSE: GSF) with an estimated enterprise value of approximately $53 billion.

The combined company retains the Transocean name with offices in Houston and the New York Stock Exchange symbol RIG. GlobalSantaFe shares are no longer listed.

Transocean shareholders received $33.03 in cash and 0.6996 share of the combined company per Transocean share and GlobalSantaFe shareholders received $22.46 in cash and 0.4757 share per GlobalSantaFe share. The cash portion totals some $15 billion. The combined company has some 318 million shares outstanding.

GlobalSantaFe provides offshore drilling primarily in the Gulf of Mexico, the North Sea, West Africa, the Mediterranean Sea, southeastern Asia, South America, the Middle East and eastern Canada. As of year-end 2006, the company owned and operated a fleet of 59 marine drilling rigs, including 43 cantilevered jackups, 11 semisubmersibles, three drillships and two additional semisubmersibles.

Transocean provides offshore drilling primarily in the Far East, India, Gulf of Mexico, U.K., Nigeria, the Mediterranean and Middle East, Brazil, Norway, other West African countries, Australia, Canada, the Caspian Sea and Venezuela. As of Feb. 2, the company owned and operated 82 mobile offshore and barge drilling units, including 33 high-specification semisubmersibles and drillships, 20 floaters, 25 jackup rigs and four other rigs.

GlobalSantaFe president and chief executive Jon A. Marshall is now president and chief operating officer of Transocean. GlobalSantaFe chairman Robert E. Rose is now chairman of Transocean. Transocean chief executive Robert L. Long will remain CEO.

The cash portion of the deal was funded from a one-year bridge loan from Goldman, Sachs & Co. and Lehman Brothers Inc.

Goldman Sachs was financial advisor to Transocean and Lehman Brothers was financial advisor to GlobalSantaFe. Simmons & Co. International provided a fairness opinion to GlobalSantaFe.

Standard & Poor’s Ratings Services has affirmed Transocean’s BBB+ credit rating and negative outlook. It withdrew its BBB+ rating on GlobalSantaFe. S&P analyst Jeffrey B. Morrison says, “We believe that backlog-supported cash flow will allow Transocean to reduce its high initial debt burden expediently over the next two years.”