Section multiple attenuator

Claim 1

A method of suppressing multiple reflection energy in an electrical seismic trace comprising the steps of: a. generating an electrical seismic trace representing the resultant seismic waves detected at a receiving location in response to a seismic disturbance created at a sending location, and b. causing an automatically operable system to perform the steps of: i. generating an electrical auto-correlation function of said electrical seismic trace, ii. generating an electrical cross-correlation function of said electrical seismic trace and said electrical seismic trace delayed a time interval of the order of the record time of the primary reflection energy and over a time gate which excludes the primary reflection energy in said electrical seismic trace, iii. generating control signals responsive to said electrical auto-correlation and cross-correlation functions proportional to said electrical cross-correlation function divided by said electrical auto-correlation function, iv. successively time shifting said electrical seismic trace to produce a plurality of electrical traces and relatively modifying the electrical traces in response to said control signals, and v. summing the time shifted and modified electrical traces to produce a composite electrical output trace.

Claim 2

A method of suppressing multiple reflection energy in an electrical seismic trace comprising the steps of: a. generating an electrical seismic trace representing the resultant seismic waves detected at a receiving location in response to a seismic disturbance created at a sending location, and b. causing an automatically operable system to perform the steps of: i. generating an electrical auto-correlation function of said electrical seismic trace, ii. generating an electrical cross-correlation function of said electrical seismic trace and said electrical seismic trace delayed a time interval of the order of the record time of the primary reflection energy and over a time gate which excludes the primary reflection energy in said electrical seismic trace, iii. generating control signals responsive to said electrical auto-correlation and cross-correlation functions proportional to said electrical cross-correlation function divided by said electrical auto-correlation function, iv. successively time shifting said electrical seismic trace to produce a plurality of electrical traces and relatively modifying the electrical traces in response to said control signals, and v. summing the time shifted and modified electrical traces to produce a composite electrical output trace.

Claim 3

A method of suppressing multiple reflection energy in an electrical seismic trace, comprising the steps of: a. creating a seismic disturbance, b. detecting the resultant seismic waves and producing an electrical seismic signal representative thereof, and c. causing an automatically operable system to perform the steps of: i. generating an electrical auto-correlation function of said electrical seismic trace, ii. generating an electrical cross-correlation function of said electrical seismic trace and said electrical seismic trace delayed a time interval of the order of the record time interval of the primary reflection energy and over a time gate which excludes the primary reflection energy in said electrical seismic trace, iii. generating control signals responsive to said electrical auto-correlation and cross-correlation functions proportional to said electrical cross-correlation function divided by said electrical auto-correlation function, iv. applying said electrical seismic trace to an uneven number of channels, v. successively time shifting the electrical traces in some of said channels in a positive direction with respect to the electrical trace in one of said channels, vi. successively tIme shifting the electrical traces in the other of said channels in a negative direction with respect to the electrical trace in said one of said channels, vii. relatively modifying the electrical traces in said channels in accordance with said control signals, and viii. summing the time shifted and modified electrical traces from said channels with the polarity of the electrical signal in said one of said channels reversed.

Claim 4

A method of suppressing multiple reflection energy in an electrical seismic trace, comprising the steps of: a. creating a seismic disturbance, b. detecting the resultant seismic waves and producing an electrical seismic signal representative thereof, and c. causing an automatically operable system to perform the steps of: i. generating an electrical auto-correlation function of said electrical seismic trace, ii. generating an electrical cross-correlation function of said electrical seismic trace and said electrical seismic trace delayed a time interval of the order of the record time interval of the primary reflection energy and over a time gate which excludes the primary reflection energy in said electrical seismic trace, iii. generating control signals responsive to said electrical auto-correlation and cross-correlation functions proportional to said electrical cross-correlation function divided by said electrical auto-correlation function, iv. applying said electrical seismic trace to an uneven number of channels, v. successively time shifting the electrical traces in some of said channels in a positive direction with respect to the electrical trace in one of said channels, vi. successively tIme shifting the electrical traces in the other of said channels in a negative direction with respect to the electrical trace in said one of said channels, vii. relatively modifying the electrical traces in said channels in accordance with said control signals, and viii. summing the time shifted and modified electrical traces from said channels with the polarity of the electrical signal in said one of said channels reversed.

Claim 5

A method of suppressing multiple reflection energy in an electrical seismic trace comprising the steps of: a. creating a seismic disturbance and detecting the resultant seismic waves to produce an electrical seismic trace representative thereof, and b. causing an automatically operable system to perform the steps of: i. storing said electrical seismic trace in at least two independently reproducible forms, ii. cyclically reproducing the stored electrical seismic traces with successive changing time delays 035 Tau to produce an electrical auto-correlation function of said electrical seismic trace, iii. cyclically reproducing the stored electrical seismic traces with successively changing time delays T + or - Tau to produce an electrical cross-correlation function, where T is a time shift between the electrical seismic traces of the order of the record time producing primary reflection energy and any multiple thereof at a record time of 2T, iv. generating control signals responsive to said electrical cross-correlation and auto-correlation functions proportional to said electrical cross-correlation function divided by said electrical auto-correlation function, v. reproducing one of said stored electrical seismic traces, vi. successively time shifting the reproduced electrical seismic trace to produce a plurality of time shifted electrical traces, modifying said plurality of time shifted electrical traces in accordance with said control signals, and vii. summing said time shifted and modified electrical traces to produce a composite electrical output trace.

Claim 6

A method of suppressing multiple reflection energy in an electrical seismic trace comprising the steps of: a. creating a seismic disturbance and detecting the resultant seismic waves to produce an electrical seismic trace representative thereof, and b. causing an automatically operable system to perform the steps of: i. storing said electrical seismic trace in at least two independently reproducible forms, ii. cyclically reproducing the stored electrical seismic traces with successive changing time delays 035 Tau to produce an electrical auto-correlation function of said electrical seismic trace, iii. cyclically reproducing the stored electrical seismic traces with successively changing time delays T + or - Tau to produce an electrical cross-correlation function, where T is a time shift between the electrical seismic traces of the order of the record time producing primary reflection energy and any multiple thereof at a record time of 2T, iv. generating control signals responsive to said electrical cross-correlation and auto-correlation functions proportional to said electrical cross-correlation function divided by said electrical auto-correlation function, v. reproducing one of said stored electrical seismic traces, vi. successively time shifting the reproduced electrical seismic trace to produce a plurality of time shifted electrical traces, modifying said plurality of time shifted electrical traces in accordance with said control signals, and vii. summing said time shifted and modified electrical traces to produce a composite electrical output trace.

Claim 7

The method of multiple suppression in seismic exploration which comprises: a. generating and detecting seismic waves to produce a seismic signal trace which includes a primary reflection, and b. causing an automatically operable system to perform the steps of: i. generating an auto-correlation function X of said signal trace for a plurality of delay intervals, ii. generating a cross-correlation function Z for said plurality of delay intervals between (1) said signal trace undelayed and (2) said signal trace delayed a time interval of the order of the record time of the primary reflection and over a time gate which excludes the primary reflection in the undelayed signal trace, and iii. time domain filtering said signal with relative amplitudes proportional to (Ym) in the matrix (Ym) X Z to suppress any multiple of said primary reflection in said signal trace at a record time of the order of twice the time of said primary reflection.

Claim 8

The method of multiple suppression in seismic exploration which comprises: a. generating and detecting seismic waves to produce a seismic signal trace which includes a primary reflection, and b. causing an automatically operable system to perform the steps of: i. generating an auto-correlation function X of said signal trace for a plurality of delay intervals, ii. generating a cross-correlation function Z for said plurality of delay intervals between (1) said signal trace undelayed and (2) said signal trace delayed a time interval of the order of the record time of the primary reflection and over a time gate which excludes the primary reflection in the undelayed signal trace, and iii. time domain filtering said signal with relative amplitudes proportional to (Ym) in the matrix (Ym) X Z to suppress any multiple of said primary reflection in said signal trace at a record time of the order of twice the time of said primary reflection.