Journal of Petroleum Geology, Vol.3, No.3, pp. 455-476, 1981

©Copyright 2000 Scientific Press, Ltd.

ON THE THEORY OF GROWTH FAULTING
PART II(c): GENESIS OF THE "UNIT"

W. Crans and G. Mandl

This research work was carried out in the Koninklijke/Shell Exploratie en Produktie Laboratorium, Rijswijk, The Netherlands during 1968-1972 by Dr. W. Crans, Exploration Consultant, Crans & Assoc. International lnc., c/o SNEA(P), Tour General, La Defence 9, Cedex 22, 92088 Paris La Defence, France, and Dr. G. Mandl, Koninklijke/Shell Exploratie en Produktie Laboratorium, Rijswij, The Netherlands. Some basic features have been published previously in short notes by Crans, Mandl and Shippam (1973) and Mandl and Crans (1979).

Abstract

This paper forms the third and concluding section of the second part of a detailed and rigorous geomechanical analysis of the stability of overpressured, gently-sloping sediment layers presented in the Journal of Petroleum Geology, 2, 3, 1980 and 3, 2, and 3, 3, 1981. Parts II(a) and (b) considered stress equilibrium, related stress equations, types of overpressure, the representation of the stress state in Mohr space, and the plastic/elastic states of frictional materials in long fluid-filled layers, together with numerical and analytical examinations of slip lines and considerations of plastic flow and slip. This concluding section introduces the effects of peak-strength and liquefaction phenomena, together with a consideration of the behaviour of purely cohesive materials, and contains also the six important conclusions derived from this study.