Direct determination of stacking velocities in three dimensional seismic prospecting

Claim 1

Apparatus comprising: at least first and second seismic receivers located on a first line, wherein said first line originates at a point M; at least third and fourth seismic receivers located on a second line, wherein said second line originates at said point M; at least fifth and sixth seismic receivers located on a third line, wherein said third line originates at said point M; means for generating acoustic waves in the earth at at least first, second, third, fourth, fifth and sixth seismic source locations, wherein said first and second seismic source locations are on a fourth line which is an extension of said first line from said point M, wherein said third and fourth seismic source locations are on a fifth line which is an extension of said second line from said point M, wherein said fifth and sixth seismic source locations are on a sixth line which is an extension of said third line from said point M, wherein said first seismic source location and said first seismic receiver are substantially equidistantly spaced from said point M, wherein said second seismic source location and said second seismic receiver are substantially equidistantly spaced from said point M, wherein said third seismic source location and said third seismic receiver are substantially equidistantly spaced from said point M, wherein said fourth seismic source location and said fourth seismic receiver are substantially equidistantly spaced from said point M, wherein said fifth seismic source location and said fifth seismic receiver are substantially equidistantly spaced from said point M, and wherein said sixth seismic source location and said sixth seismic receiver are substantially equidistantly spaced from said point M; means for activating said means for generating acoustic waves so as to impart acoustic waves into the earth at said first seismic source location, said second seismic source location, said third seismic source location, said fourth seismic source location, said fifth seismic source location and said sixth seismic source location at desired times, wherein said first seismic receiver provides a first output signal in response to the generation of acoustic waves at said first seismic source location, wherein said second seismic receiver provides a second output signal in response to the generation of acoustic waves at said second seismic source location, wherein said third seismic receiver provides a third output signal in response to the generation of acoustic waves at said third seismic source location, wherein said fourth seismic receiver provides a fourth output signal in response to the generation of acoustic waves at said fourth seismic source location, wherein said fifth seismic receiver provides a fifth output signal in response to the generation of acoustic waves at said fifth seismic source location, and wherein said sixth seismic receiver provides a sixth output signal in response to the generation of acoustic waves at said sixth seismic source location; means for determining a first stacking velocity in the direction of said first and fourth lines in response to said first and second output signals, for determining a second stacking velocity in the direction of said second and fifth lines in response to said third and fourth output signal, and for determining a third stacking velocity in the direction of said third and sixth lines in response to said fifth and sixth output signals; and means for determining the equation of an ellipse based on the magnitude of said first stacking velocity, the magnitude of said second stacking velocity and the magnitude of said third stacking velocity, wherein the equation of said ellipse determines the stacking velocity in any direction about said point M.

Claim 5

A method for determining the stacking velocity in any direction around a common midpoint M comprising the steps of: generating acoustic waves in the earth at a first seismic source location on a first line which originates at said common midpoint M; establishing a first output signal representative of the output of a first seismic receiver located on a second line which is an extension of said first line from said common midpoint M, wherein said first seismic source location and said first seismic receiver are substantially equidistantly spaced from said common midpoint M; generating acoustic waves in the earth at a second seismic source location on said first line; establishing a second output signal representative of the output of a second seismic receiver located on said second line wherein said second seismic source location and said second seismic receiver are substantially equidistantly spaced from said point M; generating acoustic waves in the earth at a third seismic source location on a third line which originates at said common midpoint M; establishing a third output signal representative of the output of a third seismic receiver located on a fourth line which is an extension of said third line from said common midpoint M, wherein said third seismic source location and said third seismic receiver are substantially equidistantly spaced from said common midpoint M; generating acoustic waves in the earth at a fourth seismic source location on said third line; establishing a fourth output signal representative of the output of a fourth seismic receiver located on said fourth line, wherein said fourth seismic source location and said fourth seismic receiver are substantially equidistantly spaced from said common midpoint M; generating acoustic waves in the earth at a fifth seismic source location on a fifth line which originates at said common midpoint M; establishing a fifth output signal representative of the output of a fifth seismic receiver located on a sixth line which is an extension of said fifth line from said common midpoint M, wherein said fifth seismic source location and said fifth seismic receiver are substantially equidistantly spaced from said common midpoint M; generating acoustic waves in the earth at a sixth seismic source location on said fifth line which originates at said common midpoint M; establishing a sixth output signal representative of the output of a sixth seismic receiver located on said sixth line, wherein said sixth seismic source location and said sixth seismic receiver are substantially equidistantly spaced from said common midpoint M; determining a first stacking velocity in the direction of said first and second lines in response to said first and second output signals; determining a second stacking velocity in the direction of said third and fourth lines in response to said third and fourth output signals; determining a third stacking velocity in the direction of said fifth and sixth lines in response to said fifth and sixth output signals; and determining the equation of an ellipse based on the magnitude of said first stacking velocity, the magnitude of said second stacking velocity and the magnitude of said third stacking velocity, wherein the equation of said ellipse determines the stacking velocity in any direction about said common midpoint M.

Claim 6

A method for determining the stacking velocity in any direction around a common midpoint M comprising the steps of: generating acoustic waves in the earth at a first seismic source location on a first line which originates at said common midpoint M; establishing a first output signal representative of the output of a first seismic receiver located on a second line which is an extension of said first line from said common midpoint M, wherein said first seismic source location and said first seismic receiver are substantially equidistantly spaced from said common midpoint M; generating acoustic waves in the earth at a second seismic source location on said first line; establishing a second output signal representative of the output of a second seismic receiver located on said second line wherein said second seismic source location and said second seismic receiver are substantially equidistantly spaced from said point M; generating acoustic waves in the earth at a third seismic source location on a third line which originates at said common midpoint M; establishing a third output signal representative of the output of a third seismic receiver located on a fourth line which is an extension of said third line from said common midpoint M, wherein said third seismic source location and said third seismic receiver are substantially equidistantly spaced from said common midpoint M; generating acoustic waves in the earth at a fourth seismic source location on said third line; establishing a fourth output signal representative of the output of a fourth seismic receiver located on said fourth line, wherein said fourth seismic source location and said fourth seismic receiver are substantially equidistantly spaced from said common midpoint M; generating acoustic waves in the earth at a fifth seismic source location on a fifth line which originates at said common midpoint M; establishing a fifth output signal representative of the output of a fifth seismic receiver located on a sixth line which is an extension of said fifth line from said common midpoint M, wherein said fifth seismic source location and said fifth seismic receiver are substantially equidistantly spaced from said common midpoint M; generating acoustic waves in the earth at a sixth seismic source location on said fifth line which originates at said common midpoint M; establishing a sixth output signal representative of the output of a sixth seismic receiver located on said sixth line, wherein said sixth seismic source location and said sixth seismic receiver are substantially equidistantly spaced from said common midpoint M; determining a first stacking velocity in the direction of said first and second lines in response to said first and second output signals; determining a second stacking velocity in the direction of said third and fourth lines in response to said third and fourth output signals; determining a third stacking velocity in the direction of said fifth and sixth lines in response to said fifth and sixth output signals; and determining the equation of an ellipse based on the magnitude of said first stacking velocity, the magnitude of said second stacking velocity and the magnitude of said third stacking velocity, wherein the equation of said ellipse determines the stacking velocity in any direction about said common midpoint M.