Pressurized MudCap Drilling (PMCD), a variant of Managed Pressure Drilling (MPD), is known for allowing drilling to continue despite a total loss of circulation, while at the same time monitoring and controlling the entry of influx into the wellbore. A weakness of this technique is that the well still has to be killed prior to pulling out of the hole, which can be timeconsuming and ultimately lead to reservoir damage. Utilizing a downhole isolation system to eliminate the need to kill the well during and after PMCD operations would therefore greatly improve the efficiency and effectiveness of this drilling technique and enhance its acceptability in operations where well productivity is a major consideration.

A combination of MPD and downhole isolation technologies was recently used successfully to drill a highly prolific, fractured gas reservoir in Suban Field, South Sumatra, Indonesia, resulting in wells capable of producing in excess of 300 mmscfd. MPD with downhole isolation allowed drilling to continue even with total loss of circulation, increased the safety margin of operations, reduced the amount of mud and lost circulation materials (LCM) required, minimized formation damage and made the running and installation of the completion assembly possible without the need to kill the well. The project demonstrated the clear and practical advantage that can be gained from combining these two technologies.

This paper focuses on how MPD and downhole isolation technologies were successfully integrated to produce high-rate gas wells in the Suban field and details how the system was effectively utilized for the first time to produce improvements in the safety and efficiency of drilling and completion operations, as compared to previous methods used in the area. It will also present the equipment, set-up, processes and procedures used in integrating these two technologies.

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