Coiled Tubing (CT) catenary technology supports the possibility of executing offshore interventions on platforms with space and weight limitations. Having the majority of the CT equipment remain on a separate support vessel vastly increases the platform working area and minimizes offshore heavy lifting. The system allows the operation of well control and pumping equipment from the vessel for a single control source and an overall faster, safer, lower-cost operation.

Limited offshore platform space and crane capacity are a significant concern for intervention operations in the Gulf of Thailand. A conventional CT unit is simply unable to fit on a small offshore facility. The catenary system was introduced to eliminate these limitations by keeping the main CT equipment on the vessel while providing the connection and interface between the vessel and platform equipment, allowing a safe and efficient operation. It also has the flexibility to enable the vessel to adjust its location during bad weather if required, without affecting the overall safety of the operation. The same system can also be used on regular platforms without space and weight limitations during the same campaign.

The catenary system saved two days per well, resulting in savings due to less equipment utilization, reduced personnel, and accommodation requirements, and reduced consumables used. Less heavy lifts also saved time, associated costs, and increased safety during the preparation phase. The CT operator can also load the maximum length of CT pipe onto the vessel without concerns about having to join multiple strings or using split reel spooler equipment. All well control equipment was function tested and operated as standard with real-time monitoring and capturing of well conditions, operation parameters, and CT fatigue the same as expected from a conventional CT setup. The paper will elaborate on the catenary principles, concepts, and engineering background for these types of operations.

The CT catenary was proven to bring significant efficiency improvements, safety enhancements, and faster operations, leading to cost-saving when carrying out CT interventions in the Gulf of Thailand. The techniques and details will be elaborated on in the paper.

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