Workflow for Uncertainty Modelling of Pore Pressure and Mud Weight Window ahead of Bit - Example of Pre-drill Results from the North Sea

In this work we present a workflow for how uncertainties of pore pressures and mud weight window prediction can be quantified and updated while drilling. With new updates of the pressures along the well, updated prognosis can be made ahead of the bit. Pre-drill models of pore pressure prediction is carried out using a basin modelling Monte-Carlo approach. The most likely pressure curve along a planned well, is used as input to calculate the corresponding mud weight window. During a drilling operation, new pressure measurements from the well can be used to update the drilling prognosis ahead of the bit. A case study from the North Sea is used as an example for the work flow.