First Offshore Coiled Tubing Intervention Using a Catenary System in the Gulf of Mexico
Coiled tubing (CT) operated from a floating anchored vessel (FAV) was
developed for well intervention in offshore locations where crane limitations
and deck loading constrains imposes various limitations on the ability to
perform workover operations. This tailor-made solution involves the operation
of a CT unit with the tubing reel located on a floating anchored vessel and the
injector head positioned on the offshore platform. Today, CT operations
supported by a FAV are routinely performed in several countries, including
Malaysia, Gabon, Tunisia, Brunei, Angola and the North Sea.
The first CT operation supported with a vessel in the Gulf of Mexico was
successfully performed in a non-producing well which had been shut-in for nine
months due to compatibility issues with the structure for temporary installing
service equipment and the limited availability of jack-up platforms to provide
a deck area for positioning CT equipment. As a result of this successful
operation, a new perspective of CT rigless interventions was adopted in
offshore Mexico, thus allowing the operator, to improve equipment utilization
for both CT units and workover rigs, in order to maximize oil production.
This paper details the analysis, execution and evaluation of the CT
operation from a FAV in Offshore Mexico, which includes equipment selection,
sea condition and weather-related studies, contingency planning, personnel
competency and training requirements, and logistical considerations, among
other technical factors that were critical in the implementation of such
project. As well, the benefits that were realized by the operator regarding
production enhancement and operational cost reduction are covered.