Patent ID: 6775618
Filing Date: 2004-08-10
Classification: G01V

Abstract:
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 filter 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; andanalysing 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.