Sonat Offshore in 1995. In 1996, Sonat Offshore acquired Norwegian Transocean ASA and decided to adopted the name Transocean Offshore in order to differentiate itself from its former parent company. Today Transocean is one of the largest offshore drilling contractors in the world. Sonat Marine Sonat Marine was formed in 1981 when Sonat purchased Interstate Oil Transportation Company of Philadelphia, Pennsylvania for $109 million. Interstate had been the nation's largest independent marine transporter of petroleum products. In 1987, a group of Sonat Marine executives and managers formed a partnership to acquire the company from Sonat for $234 million. References External links Sonat, Inc. FundingUniverse Natural gas companies of the United States Defunct companies based in Alabama Companies based in Birmingham, Alabama Energy in Alabama Non-renewable resource companies established in 1928 Non-renewable resource companies disestablished in 1999 1928 establishments in Alabama 1999 disestablishments in Alabama