Seismic Characterization of Fractured Reservoirs Using 3D Double Beams Available to Purchase

We propose an efficient target-oriented method to characterize seismic properties of fractured reservoirs: the spacing between fractures and the fracture orientation. We use both singly scattered and multiply scattered seismic waves from the fractures. Based on diffraction theory, the scattered wave vector is related to the incident wave vector computed from the source to the target using a background velocity model. Two Gaussian beams, a source beam constructed along the incident direction and a receiver beam along the scattered direction, interfere with each other. For given source and receiver beam frequency and directions, the reflected beam amplitude is a function of the fracture spacing and orientation. We scan a range of possible fracture spacings and orientations and output an interference pattern as a function of the spacing and orientation. If multiple targets are evaluated, the interference pattern is spatially varying and the most likely fracture spacing and orientation can be inferred. Our method is adaptive for a variety of seismic acquisition geometries. If seismic sources (or receivers) are spatially sparse, we can shrink the source (or receiver) beam-width to zero and in this case, we achieve point-source-to-beam interference. We validated our algorithm using a synthetic dataset created by a finite difference scheme with the linear-slip boundary condition, which describes the wave-fracture interaction.