Fractures play a major role in reservoir exploitation, as they act as natural pathways for fluid flow in the subsurface. They also change the rheology of rocks, generally weakening them. Knowledge of their geometrical characteristics, as well as their connectivity and fluid fill attributes are key parameters in describing fracture systems. Seismic methods can be used to characterise fractures. For example, aligned fractures are very effective in generating seismic anisotropy in a medium, where elastic wave velocities vary as a function of direction of propagation. Such anisotropy is controlled by the compliance of the fracture, which can be decomposed into normal and tangential components, ZN and ZT , respectively. As the compliance of a fracture set depends on the fluid fill properties, as well as the connectivity, the fracture compliance ratio, ZN/ZT , is a good indicator of fracture fluid properties. In this thesis, seismic anisotropy is used to characterise fracture networks and quantify ZN/ZT in two different settings.
|Date of Award||28 Nov 2019|
- The University of Bristol
|Supervisor||James M Wookey (Supervisor) & Michael Kendall (Supervisor)|