Acquisition Requirements for Inversion for Fracture Parameters with 3D DAS VSP Data

The characterization of rock fracture patterns is crucial for exploration and development of subsurface resources, and 3D DAS VSP data facilitate estimation of fracture parameters through phase slowness inversion, as these data capture azimuthal variation of P wave traveltimes. A well-designed VSP acquisition geometry is essential for reliable fracture parameter estimation, particularly for DAS VSP. This abstract presents a study on acquisition requirement for inversion for fracture parameters with 3D DAS VSP Data. The findings indicate that, for estimation of excess fracture compliance along fracture normal, dip angles for the VSP survey greater than 45o are crucial with larger aperture angles yielding more robust estimation. For the excess fracture compliance along fracture strike, dip angle range between 45 o and 60 o is particularly important. Moreover, ensuring a sufficiently high signal-to-noise ratio for high-angle DAS recordings is essential in DAS VSP survey to achieve reliable fracture parameter inversion.