Laboratory Investigation Into The Initiation And Propagation of Hydraulic Fractures
Alqudrah, A., Crosley, A. and Homoud, A.
Engineering Honours Degree, 2010
University of Adelaide
The initiation and propagation of hydraulic fractures induced in core samples through the use of a specially designed hydraulic fracturing tri-axial cell was investigated. The purpose of this was to then investigate how the pH and salinity of the fracture fluid affected the initiation and propagation of fractures in core samples. To do this, artificial core samples needed to be fabricated. These cores were then used to test the performance of the tri-axial cell. Different types of artificial cores were considered and a mixture of sand, cement and water was decided on as the materials to be used to fabricate core samples with properties similar to real cores. This report discusses the mechanics involved in hydraulic fracturing, the selection of a suitable artificial core, the process followed to fabricate artificial cores, the procedure to fracture the cores using the tri-axial cell and a discussion of results from the various experiments. We were unable to confidently determine the initiation and fracture pressures of the artificial core as the plastic sleeve in the tri-axial cell failed and we had only managed to fractured one core sample when this occurred. We feel that the artificial cores were a good replacement for real core as had similar properties such as porosity and permeability in common with real core samples.