Existing "seepage-stress-damage" models are mainly used for pre-drilling prediction and post-drilling evaluation of collapse pressure. Such models involve a large number of parameters that are difficult to obtain. In this paper, the "seepage-stress-damage" model is simplified into a strength softening model applicable to real-time collapse analysis while drilling. A method is also proposed to determine the parameters of the strength softening model using logging data. Field engineers of Well X adjusted drilling fluid properties based on the strength softening model. Within 10 days of exposure, only small collapse blocks (0.2 cm × 0.23 cm) were retrieved, and the 1000 m thick clay formation in Well X was drilled efficiently.
Chen et al. (Mon,) studied this question.