Offshore Well Integrity Management with MPD Tools and Technology

Abstract

Important key performance indicators of offshore well integrity management include mitigating drilling hazards without inducing others and maintaining control of the well in the process. Offshore applications of Managed Pressure Drilling (MPD) tools and technology have been steadily increasing over the past decade primarily for these reasons. Its growing acceptance has been influenced by drilling prospects deemed to be un-drillable with conventional circulating fluids systems for safety, economic, and/or technical reasons, increasing recoverable reserves in the process. MPD's pristine onshore well control track record is now being recognized as a safer way to drill a growing number of offshore prospects that could not be drilled with a conventional open-to-atmosphere mud returns system 4 .There are four variants of MPD practiced offshore; Constant Bottomhole Pressure (CBHP), Pressurized Mud Cap Drilling (PMCD), Returns Flow Control (RFC-HSE), and Dual Gradient Drilling (DGD). CBHP for drilling in narrow, shifting or relatively unknown safe mud weight windows, PMCD for drilling in severe to total loss zones, RFC-HSE to augment safety systems and methods when drilling with an otherwise conventional fluids program, and DGD for reducing equivalent mud weight (EMW) when drilling depleted formations from shallow water rigs and eliminating gross overbalanced conditions when drilling from deepwater rigs 8 .Over the past decade, key enabling tools have been developed to enable the safe and effective practice of MPD on all types of offshore rigs and water depths; marine series rotating control devices, MPD automated control systems, MPD hydraulic flow modeling, MPD well control matrix, etc. Early kick and loss detection is a flagship capability, as well as ability to conduct formation integrity and leak-off tests more frequently than industry norm by doing so while drilling, quantify and virtually eliminate ballooning 3 , closed-loop cementing, and managed pressure wellbore strengthening, all of which represent state-of-the-art well integrity management capabilities.Whether it be in shallow water, deepwater, or ultra-deepwater, a growing number of otherwise promising prospects are deemed un-drillable with conventional circulating fluids systems. The industry has already drilled the majority of the available 'easy' wells with drilling hydraulics whose root principals were developed over a century ago. MPD is poised to become the next 'conventional' way to drill in marine environments within the next decade. This presentation will illustrate to the offshore drilling industry, regulatory and stakeholders why that is expected to be the case.