Case-based study for constructing knowledge-based methodologies of trouble in a borehole drilling; An Examples of borehole collapse in the Tono area, Gifu Prefecture, Japan

Masunaga, Kosuke; Amano, Kenji  ; Kunimaru, Takanori

We have examined field examples of several kinds of troubles and their causes and measures on a deep borehole drilling. Moreover, frequency and characteristics focussing on the borehole collapse have been studed. As a result, many of collapse has been concentrated on the specific geological structure. Further studies should be needed on the accumulation of the troubleshooting examples on the deep borehole investigations and improvement of the risk assessment methodologies based on the three-dimensional geological model etc.