High Pressure High Temperature (HPHT) fields in the North Sea continue to both push, and ultimately extend, the boundaries of what can be safely and successfully achieved through intervention with coiled tubing (CT). Within the last six years successful CT deployed perforating operations have become relatively common. However, as more and more HPHT fields consider intervention operations, existing technologies are subsequently examined and re-examined to suit the particular well criteria and also the actual operating environment of the particular offshore installation.

This paper begins by discussing the types of equipment that are required for HPHT CT intervention. It then presents a number of recent case histories concerning CT interventions on HPHT fields. Three of these case histories involve different underbalance perforating operations. Case histories concerning cementing operations through CT are also discussed. The paper outlines the specific types of downhole equipment that are needed for these operations. This includes application of new equipment designs and novel solutions to both surface and downhole constraints.

Lessons learned from each of the case histories will be presented together with an overview of the requirement that HPHT fields and the related CT intervention technologies are moving towards. Conclusions will be drawn from these different case histories and a discussion presented on the potential extension for CT intervention in HPHT environments.

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