Folds and Tensile Fractures in Stratified Rocks: A Synthesis of Analogue Experiments, Analytical and Numerical Methods

Folds and Tensile Fractures in Stratified Rocks This work tries to contribute to the development of quantitative tools for an objective interpretation, based on mechanical equilibrium and material strength of folds, which can be potential oil reservoirs. Furthermore, the objective is to improve the prediction of fracture distributions in layered sequences, which control the permeability. Experiments, analytical and numerical results are presented on the onset and evolution of folds and fractures, which happens at different scales. Analogue experiments, conducted in the Shell-Laboratory in Rijswijk, The Netherlands are discussed. The outcomes are compared with results obtained by a theoretical study. A geometrical imperfection and activation of bed parallel slip is shown to be essential for the creation of folds to be more likely compared to other failure modes (thrusting, compaction bands). Interfacial properties in a multilayered setting are also affecting the fracture spacing. Saturation is linked to the delamination of the interface between the layer and its foundation. At last, a new experimental device for the study of bending fractures is introduced.