Over the last years the oil and gas Mexican operator’s exploration and development programs are becoming more challenging due to the complex conditions where hydrocarbons are found today. One of the areas that have seen a decline on production over the years is the offshore. As an alternative to find new sources of oil that overcome the current production decline in the area, the operator is drilling new wells where the operational capabilities of the equipment are put out of their limits. These new wells are drilled at depths beyond the conventional 5,000-m (16,400-ft) with bottom hole pressures as high as 15,000-psi and temperature over 180°C requiring that the equipment providing the services over their producing life reach their own limitations and in some cases re-engineering of the design and process has to be done.

In some cases, minimum changes to the equipment or processes are enough; however, a service of such complexity as the use of Coiled Tubing (CT) requires a major review of all the components of the operation to be completed in order to reach the new targets without jeopardizing the safety of the operations and/or compromising the production of the well.

This paper details the CT string design criteria to reach the deeper vertical depths with high wellbore mechanical friction coefficients while withstanding high pressures; equipment selection, to allow greater CT length capacity on reel and higher pulling capacity on injector head; platform and crane specifications to withstand over dimensioned equipment, as well as, a case study to analyze equipment and CT string performance for interventions on these types of wells.

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