Borehole Geomechanics in Petroleum Exploration and Development: From Controlling Wellbore Stability to Predicting Fault Seal Integrity

Few in the Australian oil patch were familiar with the term 'borehole breakout' when David Lowry alerted PESA Journal readers to this phenomenon (1990, v.17, p. 43-44). Ten years later, few are unfamiliar, with breakouts having been reported in every Australian basin subject to significant drilling activity. This change witnesses the dramatically increased awareness of borehole geomechanics in the Australian oil patch that has developed over the last decade. One driver for this increased awareness has been the increasing quality and use of borehole imaging tools, and the geomechanical information yielded by these tools. Furthermore, borehole geomechanics has applications that are particularly significant for, although by no means restricted to, deviated wells. Hence the increased incidence of deviated drilling has been another driver. That significant fundamental research on the origin of crustal stresses and their application in the oil patch has been undertaken in Australia, both in the universities and at CSIRO, has been another driver for the uptake of borehole geomechanics in the Australian oil patch over the last decade. This article provides a contemporary snapshot of borehole geomechanics in the oil patch, addressing specifically, the methodology of in situ stress determination, and some key applications of knowledge of subsurface stresses.