Description
In spite of more than 20 years of advances in the application of geomechanical principles to improve understanding of its causes and improvements in drilling practices to reduce its effects, wellbore instability continues to be perhaps the largest single source of non-productive drilling time. Costs associated with overly conservative drilling and casing designs which are required to reduce uncertainties in predictions are unknown.
These uncertainties arise largely because of lack of the appropriate rock properties data and information about the magnitudes and orientations of in situ stresses. This talk will briefly review the history of application of geomechanics to wellbore design, will discuss the sources of data required to reduce uncertainties, the ways in which to recognize the causes of instabilities to allow appropriate remediation, and the pros and cons of various models currently in use within the oilfield.