| abstract |
A method for spectral balancing of near- and far-offset seismic data, whereby velocity and offsets are determined for the seismic data. First, an NMO stretch compensation filter is created by the following steps. A frequency spectrum of the near-offset seismic data is estimated and a stretch factor beta is calculated for the frequency spectrum, using the velocity and the offsets. A stretched frequency spectrum of near-offset seismic data is calculated, based on the stretch factor beta. The frequency spectrum of near-offset seismic data is divided by the stretched frequency spectrum of near-offset seismic data, generating a first frequency response filter. High frequency gain is limited in the first frequency response filter, generating a first gain-limited filter. The first gain-limited filter is convolved with a low pass filter, generating the NMO stretch compensation filter. Then the NMO stretch compensation filter is applied to the seismic data. Second, a relative Q compensation filter is created by the following steps. A difference in amplitude loss between the near- and far-offset seismic data is calculated, using the velocity and the offsets. A frequency gain is calculated, based on the difference in amplitude loss. A second frequency response filter is created, based on the frequency gain. High frequency gain is limited in the second frequency response filter, generating a second gain-limited filter. The second gain-limited filter is convolved with a low pass filter, generating the relative Q compensation filter. The relative Q compensation filter is applied to the seismic data. |