July 26, 2020

The first floating drilling experiments were performed in 1953 near the coast of California, using the M.V. Submarex. With leasing from the state of California to explore and produce oil and gas, well control and the ability to run multiple strings of casing became mandatory and required a totally new, unproven technology. The M. V. Submarex was a 300-ton ex-Navy wooden hulled patrol craft owned and operated by a group named CUSS that included Conoco, Union Oil of California, The Superior Oil, and Shell Oil. The vessel was equipped with a small drilling rig and experiments were performed to develop a method of drilling from the vessel. By 1954, the art of this type of drilling, which incorporated the features of hole re-entry – return circulation – and blowout prevention, was reduced to a practical exploratory method.
After being laid up, the Submarex was reactivated in 1959 at Long Beach, California. The ship was moved to the US East Coast then to the St. Lawrence seaway and into Lake Michigan to perform underwater TV surveys. The ship was then used to drill an exploratory hole in Lake Erie for El Paso Natural gas and recover sediment cores from the bottom of Lake Superior. The Submarex returned to Long Beach. After almost sinking alongside its peer, the world’s first moored drillship was sold for scrap in 1965.
The first floating drilling rig to use subsea well control was the Western Explorer owned by Chevron, which spudded its first well in 1955 in the Santa Barbara Channel. Subsea BOP equipment mounted near the seafloor included a circulating head and remote latching mechanism manufactured by Shaffer Tool Works of Long Beach, California. Individual hoses bundled together and attached to the drilling riser controlled the equipment. Others followed quickly, with all of them concerned about the marine environment and technology to allow drilling in rough weather.
(Source: Deep Challenge Clyde W. Burleson – Image: Submarex vessel/Great Lakes Institute)