Optimization of MPD and Drilling fluid parameters for narrow pressure margin wells
Abstract
The last ten years have witnessed a growing interest in the evolution of technologyand autonomous systems in drilling operations after the oil and gas companies realized that the next stage in the exploration and production of oil gas is to drillmore wells, often characterized by narrow pressure margins. The drilling challengesin narrow margin pressure wells such as depleted reservoirs, deep water, extended-reach wells (ERD) and High-Pressure High Temperature (HPHT) wells require moreaccuracy and high sensitivity in drilling operations. These wells are more susceptibleto drilling incidents such as formation influx, lost circulation, and pack-off, leadingto increased non-productive time (NPT) and increased costs.The introduction of the automation process in drilling systems based on automatedtools during drilling operations such as wired drill pipe (WDP) and along-string measurements (ASM) was required to reduce the NPT, thus reducing the drilling costsand keeping the humans away from the hazardous area. Additionally, an automatedthe system is intended to optimize the drilling operations by monitoring, modelling andcontrolling the acquisition data, which are real physical measurements transmittedfrom the well downhole.The Managed Pressure Drilling (MPD) methodology with different variants andtechniques is seen to be a promising solution during drilling operations in narrowpressure margin wells compared to conventional drilling methods. By utilizing automated back-pressure control, together with a more accurate flow meter, such as theCoriolis flowmeter, it is possible to react rapidly to any unindented influx and tocompensate for pressure variations during circulation and connection.Drilling fluid properties and rheology play an essential role during drilling operations.Choosing the proper mud density, viscosity, and rheology is a key to maintainingequivalent circulating density (ECD) between formation pore pressure gradient andfracture pressure gradient, thus avoid drilling problems such as formation influx,lost circulation and stuck pipe.In this thesis, the OpenLab drilling simulator provides synthetic measurements thatare used to create a workflow algorithm that selects the optimum set-points forMPD back-pressure and drilling fluid properties. Optimization of the MPD methodand selecting proper drilling fluid properties during drilling help to maintain thebottom-hole pressure (BHP) and prevent lost circulation, kick occurring and otherdrilling incidents and thus maintain the wellbore in safe mode.