Planning has always been essential to create and maintain a safe drilling environment. Safety and environmental concerns are now a larger concern than ever before with the increasing difficulty in drilling projects and the more sensitive environmental areas that wells are being constructed and produced from. This is increasingly becoming a bigger concern with the potential opening of new offshore and onshore areas that have been until recently not accessible to exploration and production primarily from an environmental aspect or proximity to large population centers.
Using an open-to-the-atmosphere fluids returns system when drilling with hazardous, or any, drilling fluids or into formations that could potentially have high concentrations of toxic gases or unknown shallow geo hazards, raises significant health, safety and environmental concerns. These hazards along with the complex wells with tight margins between pore pressure and fracture gradient increase risk to an intolerable level. Of course these issues have to be considered while still maintaining the same constraints of minimizing cost and enhancing drilling performance.
Managed Pressure Drilling (MPD) is a methodology that has been developed and practiced over the past few years with great success to aid in the mitigation of known and unknown drilling hazards. MPD utilizes conventional techniques and technologies to create a closed and pressurizable drilling fluids returns system that works to better predict and control the reactions of the formation to the drilling program. Planning a well with MPD as an option will preserve the same conventional drilling methods and controls but give knowledge and the technology to better mitigate against hazards and more securely maintain well control.
This paper will describe the processes and variations, and the technologies used with MPD. It will further detail how MPD techniques are applied to a variety of operations to increase both drilling efficiencies and the overall safety of the operation.