Undrained Shear Behaviour of Some UK Mudrocks Explained by Petrology
The undrained shear behaviour of mudrocks is important in petroleum engineering; for instance, when performing wellbore stability analyses. In this paper, the undrained shear behaviour of mudrocks is investigated experimentally, and the observed results are explained in terms of the petrographical properties of the tested materials. Tests were conducted on Kimmeridge clay, which was sampled from two sites in the UK. The two samples have undergone different burial histories and different diagenetic reactions. Rock mechanical tests under high confining stresses are performed to examine the undrained deformation properties, effective stress path, and peak-and post-peak shear strengths of the two types of mudrock. The geological properties of the samples, including texture, mineralogy, and diagenetic minerals, have been investigated by X-Ray diffraction, various types of scanning electron microscopy, and optical microscopy. The results are compared with those from other UK mudrocks. The study shows that both the primary depositional mineralogy and the burial history affect the undrained shear behaviour of mudrocks. It is also seen that diagenetic reactions greatly increase both the undrained peak strength and shear stiffness of mudrocks.
R. Nygaard and M. S. Gutierrez, "Undrained Shear Behaviour of Some UK Mudrocks Explained by Petrology," Journal of Canadian Petroleum Technology, vol. 41, no. 12, pp. 37-46, Canadian Institute of Mining, Dec 2002.
Geosciences and Geological and Petroleum Engineering
Keywords and Phrases
Mineralogy; Optical microscopy; Rocks; Scanning electron microscopy; Shear deformation; Shear strength; Shear stress; X ray diffraction analysis; Mudrocks; Petrology
International Standard Serial Number (ISSN)
Article - Journal
© 2002 Canadian Institute of Mining, All rights reserved.
01 Dec 2002