Michael J. Nelson Exxon Co. U.S.A. New Orleans
In October 1992, Exxon Pipeline Co., Houston, performed in the Gulf of Mexico what the company believes to have been -the first underwater freeze-plug procedure.
To form a plug, water in a small section of the pipe is frozen with liquid nitrogen.
In partially replacing a 10-in. riser at South Marsh Island Block 6A (Fig. 1), Exxon Pipeline worked closely with a freeze-plug service company to minimize environmental and personnel exposure and to avoid the chance of an oil spill.
The freeze plug reduced the time the pipe was open-ended during the repair, and hydrote...