Method for processing surface detected seismic data to plotted representations of subsurface directional seismic data

Claim 1

A method for the complete automatic plotting of directional seismic traces formed by summing geophone signals time-delayed with respect to each other, taking into account seismic velocity variations within the earth, so that the plotted mean positions of said directional traces represent actual approximate wave ray paths in the subsurface, said ray paths being both curved and distorted in scale so that the variations in amplitude along said traces represent the geologic features which gave rise to said variations in amplitude, said features being represented in approximate true subsurface depth and offset, comprising the steps of: a. machine generating amplitude values for a directional seismic trace by summing a plurality of side-by-side amplitude-versustime locational seismic traces, said locational traces being relatively time-delayed with respect to each other, b. repeating step (a) to generate amplitude values for a plurality of directional seismic traces wherein each trace corresponds to a distinct and different moveout corresponding to the difference in arrival time of the seismic waves which caused said locational traces; and c. recording at least portions of said directional seismic traces upon a display surface in a form wherein each of said directional seismic traces appears to emanate from a point representing a mean location on a datum surface within the earth under investigation, and each of said directional traces proceeds away from said point into the earth under investigation in accordance with the detected directional siesmic information it represents and in accordance with the velocity ditribution of said seismic waves within said earth under investigation.

Claim 2

A method for the complete automatic plotting of directional seismic traces formed by summing geophone signals time-delayed with respect to each other, taking into account seismic velocity variations within the earth, so that the plotted mean positions of said directional traces represent actual approximate wave ray paths in the subsurface, said ray paths being both curved and distorted in scale so that the variations in amplitude along said traces represent the geologic features which gave rise to said variations in amplitude, said features being represented in approximate true subsurface depth and offset, comprising the steps of: a. machine generating amplitude values for a directional seismic trace by summing a plurality of side-by-side amplitude-versustime locational seismic traces, said locational traces being relatively time-delayed with respect to each other, b. repeating step (a) to generate amplitude values for a plurality of directional seismic traces wherein each trace corresponds to a distinct and different moveout corresponding to the difference in arrival time of the seismic waves which caused said locational traces; and c. recording at least portions of said directional seismic traces upon a display surface in a form wherein each of said directional seismic traces appears to emanate from a point representing a mean location on a datum surface within the earth under investigation, and each of said directional traces proceeds away from said point into the earth under investigation in accordance with the detected directional siesmic information it represents and in accordance with the velocity ditribution of said seismic waves within said earth under investigation.

Claim 8

The method of producing a migrated seismic cross-section in the form of a plurality of seismic traces comprising the steps of: a. employing machine processing means to generate a directional seismic trace from a plurality of side-by-side amplitude-versus-time locational seismic traces representing seismic waves detected by a series of geophones in a geophone array positioned relative to a datum plane adjacent the surface of the earth; b. repeating step (a) to generate a plurality of directional seismic traces wherein each trace corresponds to a distinct and different moveout corresponding to the difference in arrival time of the seismic waves which created said locational seismic traces; and c. recording at least a portion of each of said plurality of directional seismic traces in a form wherein each of said directional seismic traces appears to emanate from a point on said datum plane and wherein each of said directional seismic traces proceeds away from said point into the subsurface of the earth under investigation in accordance with the detected directional seismic information it represents and in accordance with the distribution of the velocity of the seismic waves within said subsurface under investigation.

Claim 9

The method of producing a migrated seismic cross-section in the form of a plurality of seismic traces comprising the steps of: a. employing machine processing means to generate a directional seismic trace from a plurality of side-by-side amplitude-versus-time locational seismic traces representing seismic waves detected by a series of geophones in a geophone array positioned relative to a datum plane adjacent the surface of the earth; b. repeating step (a) to generate a plurality of directional seismic traces wherein each trace corresponds to a distinct and different moveout corresponding to the difference in arrival time of the seismic waves which created said locational seismic traces; and c. recording at least a portion of each of said plurality of directional seismic traces in a form wherein each of said directional seismic traces appears to emanate from a point on said datum plane and wherein each of said directional seismic traces proceeds away from said point into the subsurface of the earth under investigation in accordance with the detected directional seismic information it represents and in accordance with the distribution of the velocity of the seismic waves within said subsurface under investigation.

Claim 11

A method for the construction of a migrated seismic section, retaining the complex waveforms found on the original seismic recording, comprising: a. machine generating amplitude values for a directional seismic trace by summing a plurality of side-by-side amplitude-versus-time locational seismic traces, said locational traces being relatively time-delayed with respect to each other for a preselected moveout, b. repeating step (a) to generate amplitude values for a plurality of directional seismic traces wherein each trace corresponds to a distinct and different moveout corresponding to the difference in arrival time of the seismic waves which caused said locational seismic traces; and c. for each directional seismic trace, machine gEnerating a curved ray path of a wave front chart having the moveout of said directional seismic trace and a common reference (projection) point representing the mean location on a datum surface related to the earth''s surface of the subsurface formation under investigation, and then d. plotting at least a portion of the complex wave form of said directional seismic trace at a position along said ray path in accordance with the reflection time scale of said wave front chart so that said wave form is positioned in depth and offset to represent the migrated position of a seismic reflector in the subsurface.

Claim 12

A method for the construction of a migrated seismic section, retaining the complex waveforms found on the original seismic recording, comprising: a. machine generating amplitude values for a directional seismic trace by summing a plurality of side-by-side amplitude-versus-time locational seismic traces, said locational traces being relatively time-delayed with respect to each other for a preselected moveout, b. repeating step (a) to generate amplitude values for a plurality of directional seismic traces wherein each trace corresponds to a distinct and different moveout corresponding to the difference in arrival time of the seismic waves which caused said locational seismic traces; and c. for each directional seismic trace, machine gEnerating a curved ray path of a wave front chart having the moveout of said directional seismic trace and a common reference (projection) point representing the mean location on a datum surface related to the earth''s surface of the subsurface formation under investigation, and then d. plotting at least a portion of the complex wave form of said directional seismic trace at a position along said ray path in accordance with the reflection time scale of said wave front chart so that said wave form is positioned in depth and offset to represent the migrated position of a seismic reflector in the subsurface.