| The objectives of this thesis are to: (a) investigate the mechanisms of fracture initiation and propagation under the influence of continued water injection, (b) evaluate the effect of fracture growth on sweep efficiency, (c) improve the methods for determining fracture dimensions, (d) give rules for designing the process of waterflooding under fracturing conditions in such a way that sweep efficiency is unimpaired and vertical fracture growth is limited.;This thesis consists of five self-contained chapters. In Chapter 1 a general introduction is given, together with a survey of the work that was done in the past and of the new elements contributed by this thesis. In Chapter 2 a complete, analytical solution is given for the stress field in the reservoir rock surrounding an unfractured well.;Chapter 3 gives a description of fracture growth and the effect on sweep efficiency.;Special attention is focused on the mode of fracture propagation in which the pressure transients travel radially-symmetrically in the plane of the reservoir.;A numerical method is given for the calculation of pressure- and temperature-dependent changes in reservoir rock stress that can easily be incorporated into numerical fracture growth simulation models such as developed in the past.;Chapter 4 discusses a method for determining the dimensions of an induced fracture from a pressure fall-off test.;Finally, Chapter 5 gives a practical programme for designing the process of waterflooding under fracturing conditions in a given field in such a way that sweep efficiency is unimpaired and vertical fracture containment is ensured. (Abstract shortened with permission of author.). |
