Determination of appropriate kick tolerance to safely drill a narrow margin well can be challenging. A conventional approach using conservative assumptions and a single bubble model can lead to premature deployment of contingency casing strings or render some scenarios un-drillable. Uncertainties in pressures and depths in HPHT wells make a robust design that can handle all possible scenarios especially challenging. This paper will examine a strategy for challenging these assumptions and presents a robust methodology for safely managing ultra-low kick tolerance and large subsurface uncertainties by taking advantage of MPD influx management techniques and multi-phase modelling. The key elements defining the well control envelope include formation strength, resolution of influx detection, realistic shut-in times, safety margin and method of influx control (circulating response with MPD vs non-circulating response with BOP). This kick tolerance strategy will be implemented for a lengthy HPHT campaign in the UK North Sea. The strategy is designed to enable drilling the reservoir sections to TD and achieving all well objectives where applying a more conventional approach may require contingency casing to be deployed and key well evaluation objectives to be regretted. In addition, the well control strategy will take advantage of MPD influx management to control potential influxes within very small volumes while continuing to circulate.

The benefits of Managed Pressure Drilling are well understood in the drilling industry, but until now, they have never been integrated into a Jack-Up rig. For a UK North Sea HPHT campaign, the Drilling Contractor, Operator and MPD Service Provider collaborated for what is believed to be the World's first fully integrated, permanently installed MPD system for a Jack-Up, capable of drilling the most challenging narrow-margin HPHT wells. Overcoming the perceived complexity and cost of MPD are common obstacles. Integrating MPD systems into jack-up rigs addresses both challenges by simplifying logistics planning and operations and reducing costs. Putting MPD at the heart of the rig's drilling system offers a wealth of advantages to both the Operator and Drilling Contractor and provides ‘MPD on demand’ for all operations undertaken from the rig.