Multi-scale Fracture Analysis from an Outcrop Analogue

Abstract

Natural fractures occur over several orders of size magnitude. Accurately predicting the three-dimensional and multi-scale distribution of fractures in subsurface reservoirs is very difficult. Direct observations are limited to large-scale faults visible on seismic data and high-resolution, mostly small-scale, measurements of fractures intersecting the well, valid only in the direct vicinity of the wellbore. Analogue outcrop studies can be used to help fill in the gaps. The multi-scale properties of the natural fracture network exposed in the Cambro-Ordovician siliciclastic sequence in Petra, Jordan, are captured and it is investigated how these properties can be applied for the characterization of subsurface fractured reservoirs. The thesis consists of a series of chapters describing the geology of the study area, the results of the multi-scale fracture study in Jordan, followed by an analysis of the network connectivity using percolation theory and discrete fracture network models. The thesis is concluded by the results of numerical experiments where the influence of stress rotation on the re-activation of pre-existing fractures is investigated to help understand the evolution of complex networks consisting of multiple fracture sets.