Patent ID: RE43188

Claim:
A method of reducing the effects in seismic data of downward propagating reflected and scattered acoustic energy travelling in a fluid medium comprising the steps of: receiving pressure data representing at least the pressure in the fluid medium at a first location and a second location, the first location being in close proximity to the second location; receiving vertical particle motion data representing at least the vertical particle motion of acoustic energy propagating in the fluid medium at a third location and a fourth location, the third location being in close proximity to the fourth location, and the first, second, third and fourth locations being within a spatial area; calculating a plurality of spatial filter coefficients based in part on the velocity of sound in the fluid medium, the density of the fluid medium and a plurality of acquisition parameters, thereby creating a spatial filter which is designed so as to be effective at separating up and down propagating acoustic energy over a range of non-vertical incidence angles in the fluid medium; applying the spatial filler to the vertical particle motion data to generate filtered particle motion data; combining the filtered particle motion data with the pressure data to generate separated pressure data, the separated pressure data having up and down propagating components separated; and analysing at least part of the up or down propagating component of the separated pressure data, and wherein said vertical particle motion data is measured using one or more multi-component streamers or vertical cables having receivers located substantially above the sea floor.