Limit of crustal drilling depth

• Published in: Journal of Rock Mechanics and Geotechnical Engineering Vol. 9; no. 5; pp. 989 - 992
• Main Authors: Zhao, Y.S., Feng, Z.J., Xi, B.P., Yang, D., Liang, W.G., Wan, Z.J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2017; Key Laboratory of In Situ Property-improving Mining of Ministry of Education, Taiyuan University of Technology, Taiyuan, 030024, China%College of Mining Engineering, China University of Mining and Technology, Xuzhou, 221008, China; Elsevier
• Subjects: Borehole instability; depth;High; Drilling; Drilling well; High pressure; High temperature; instability; Limit of drilling depth; pressure;Borehole; temperature;High; well;Limit; Drilling well; Borehole instability; High temperature; Limit of drilling depth; High pressure
• ISSN: 1674-7755
• DOI: 10.1016/j.jrmge.2017.05.006

Deep drilling is becoming the direct and the most efficient means in exploiting deep mineral resources, facilitating to understanding the earthquake mechanism and performing other scientific researches on the Earth's crust. In order to understand the limit of drilling depth in the Earth's crust, we first conducted tests on granite samples with respect to the borehole deformation and stability under high temperature and high pressure using the triaxial servo-controlled rock testing system. Then the critical temperaturepressure coupling conditions that result in borehole instability are derived. Finally, based on the testing results obtained and the requirements for the threshold values of borehole deformations during deep drilling, the limit of drilling depth in the Earth's crust is formulated with ground temperature.