Quantification of the effects of fracture properties on seismic data

Fractures have significant impact on hydrocarbon production planning and management. Their properties directly determine the well location selection, drilling design and oil/gas productivity. The goal of this research is twofold. The first part is to explore and find an efficient modeling method that can describe fractures explicitly embedded in elastic media under for wave propagation modeling. The second part is to establish correlations between fracture properties and seismic response quantitatively using the modeling results. The results will provide essential information for developing a systematic characterization procedures for fractures. In the first part, the discontinuous Galerkin method (DG) is first explored for fracture modeling. Within this method, the displacement discontinuity is incorporated by using a jump function included within the shape functions commonly used in the finite element method. A single fracture model is explored using the DG method. The results are compared with the analytical solutions and found to be in close agreement. From the displacement fields, it is observed that the wave scattering is the main effect of fractures observed in seismic data. However, the expensive computational effort gives rise to challenges in conducting parametric study for several realistic models using DG methods. This poses problems in systematically understanding the effect of fractures on seismic waves. In the second part, an integral based method is implemented for the parametric studies to investigate the effect of fractures on seismic waves in elastic media. This integral based method ensures accuracy at the nodes of the elements and has greater computational efficiency. Using this algorithm, the effects of fracture spacing, density, and azimuth are investigated in a three-dimensional setting. The scattering index is used to evaluate the extent of wave scattering induced by fractures. The quantitative relationships between fracture spacing, azimuth and scattering index are established. These results provide valuable information for future fracture characterization procedures.Geological Science