Improving Coiled Tubing Operational Capabilities to Overcome New HPHT Challenges in Mexico Offshore
Over the last years the Mexican operators's offshore 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 offshore. As an alternative to find
new sources of oil that overcome the current production decline ih 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 bottomhole pressures as high
as 15,000 psi and temperature over 180ºC 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 high
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 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 capability 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.