Publications

Drilling through a formation with narrow window, may pose difficulty for the well to be drilled conventionally. A slight change in bottom hole pressure can lead to essential Non Productive Time such as handling a loss and/or kick situation. At times, underground blowout might also occur following loss and/or kick situation. In most cases, narrow operating window result in “un-drillable” well. Constant Bottom Hole Pressure (CBHP) is one of Managed Pressure Drilling (MPD) technique that is used to drill safely by maintaining bottom hole pressure value to be constantly above pore pressure and below fracture pressure by applying surface back pressure at the surface. This technique is applied by the utilization of Rotating Control Device (RCD) in conjunction with Automated MPD Choke Manifold. CBHP is one of the technique utilized to drill tight margin which require precise surface back pressure application to maintain bottom hole pressure while circulating and/or static. This paper describes CBHP as Managed Pressure Drilling technique with the use of automated system enabling to “walk-the-line” between pore and fracture pressure gradient which successfully drilled the exploration well that was considered “un-drillable” with conventional drilling technique in East Kalimantan area. The first exploration well was not able to reach TD utilizing the conventional drilling method. Application of CBHP technique was chosen to ensure that the second well will be drilled successfully while targeting the same formation. The ability to precisely control the pressure profile in the annulus where the mud weight was statically underbalanced is one of distinct advantage of Managed Pressure Drilling for drilling through steep pore pressure ramp which allow operators to reach planned target depth and perform wireline logging in afterwards.