Abstract
Implementing a stochastic approach along with the conventional wellbore stability analysis enables to take into account uncertainty from input data in order to obtain more realistic and reliable predictions which improve decision making process in drilling operations. By means of the methodology proposed, the uncertainty assessment for each parameter can be addressed through distinct methods depending on available information, and a sensitivity analysis is used as complement to the Monte Carlo Simulation to identify those lesser impact variables which can be treated as deterministic values and so that processing time is reduced.
As result of this workflow, quantified uncertainties are propagated into model and probability distributions for collapse and fracture mud weights are generated, and a mud weight window as a function of success probability for drilling without instability problems is built. Ultimately, a study case is developed to assess the probabilistic mud weight window for a drilling process in a Cretaceous Colombian formation.
