Recent MPD Application in Offshore Mahakam Depleted Formation – A Lesson Learned

Abstract

Oil and gas wells are increasingly challenging to drill. The challenge is present when drilling in a field that has been produced for a long time which has reservoir pressure depletion. The depleted reservoir significantly changes formation properties when compared to a green reservoir including pore pressure and fracture pressure as the drilling window gets narrower. This condition have meaning the pressure difference between static and dynamic conditions in the well is small, which gives limitations on equivalent circulating density.

One of the techniques to overcome these problems is the application of Weatherford's Managed Pressure Drilling (MPD) technology. MPD is a drilling method to mitigate drilling hazards by building a closed drilling fluid return system. The closed system was established by utilizing a Rotating Control Device (RCD) and an Automated MPD Choke Manifold. Applying surface back pressure to maintain downhole pressure prevents fluids from entering the wellbore and keeps wellbore pressure low enough so as not to damage the formation.

Multiple simulations with Weatherford software were carried out by using different mud densities and the sensitivity analysis as the planned drilling parameters. MPD will apply 150 psi of Surface Back Pressure to maintain ECD during connection to meet safety rules and mitigate the hazard of high pore pressure at certain formation depths.

This paper presents a case study with the main objectives are engineering preparation overview, equipment utilization, actual operational side and detailed techniques of Managed Pressure Drilling mode executed. As will be explained further from this paper, target depth was successfully and safely drilled by utilizing MPD technique.