Floating Mud-Cap Drilling Application in Exploration Well Accelerate Reaching Target Depth While Drilling Surface Hole

Abstract

The objective carbonate interval in Parigi formation often experiences total loss circulation and migration of gas to surface after losses circulation experienced which hardly to be controlled with conventional technique. In depth preparation is highly required before penetrating this carbonate formation which is known for its loss-kick cycles while drilling. Because of the secondary porosity, drilling through the highly vugular Parigi formation results in total loss circulation of the drilling fluid. Wellbore hydrostatic column instantly decreased while drilling into the loss formation.

Utilization of Rotating Control Device (RCD) eliminates the Non-Productive Time (NPT) associated with time consuming mitigation of loss – kick cycles. RCD enables close loop drilling system when the bearing assembly is installed, capping the annulus and creates pressurize-able wellbore annulus system. Completed with 18-3/4? bottom flange, the RCD was connected on top of 21-1/4? Annular BOP intermediated with a flange adapter. Parigi limestone was to be drilled with 17-1/2? bottom hole assembly to be able setting casing13-3/8? successfully.

The Mud-Cap drilling system passively seals the annulus at any time by employing the RCD bearing assembly, complementing the existing secondary well control system to prevent the direct gas release to the rig floor. During the operation, unexpected gas release were occurred while wiper trip, however the RCD was successfully kept the pressure away from the rig floor and allowed the driller to strip down the drill string back to the bottom. Details of RCD deployment and setup procedures will be elaborated in this paper.