Improved Microseismic Fracture Mapping Using Perforation Timing Measurements for Velocity Calibration

Summary A method is decribed wherein microseismic mapping of hydraulic fractures is improved by using crosswell data to calibrate and/or verify dipole-sonic-velocity data. In the perforation-timing procedure, crosswell-velocity data are obtained by monitoring the firing pulse from the receiver-orientation perforations and recording the timing pulse along with the arrivaldata. From these results, a simple one-dimensional model of velocities canbe extracted and used to validate, refine, or correct the detailed dipole-sonic data or provide a warning of discrepancies