Managed Pressure Drilling technology was deployed to drill Cairn India's first HTHP offshore well in Ravva offshore field of India. MPD feasibility study was carried out initially and this well proved as a candidate well for MPD in hole sections where narrow margin between pore pressure and fracture pressure exists. The use of MPD was further substantiated to mitigate non-productive time associated with wellbore problems like wellbore ballooning, kicks, loss circulation and stuck pipe which were encountered in offset wells. Therefore, a constant bottom hole pressure technique was chosen with mud weight closer to pore pressure & ECD profile being kept according to selected anchor point for each hole section.

The fully automated MPD set-up comprising of a rotating head (with dual sealing function), MPD choke manifold and Coriolis flow meter (6” & 4”) guided by real time hydraulic modelling was used in the well. The mud program was designed close to pore pressure in conjunction with MPD, reduce ECD while drilling and maintaining rheology at high temperature.

The deployment of MPD enabled to increase the section length of the 12.1/4” hole section (769 m), which proved to be a key step in in order to accomplish the well objectives in deeper sections. This paper by medium of actual case study talks about use of MPD technology, operational/ equipment problems faced and lessons learnt. This paper also highlights recommendations for use of MPD technology for similar wells.

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