Selective sequential input switching method for seismic surveying

Claim 1

A method of seismic exploration wherein a seismic source, and a plurality of equally spaced seismic detector groups are advanced along a traverse in a fixed horizontal relationship, seismic data recording means being provided and including a lesser number of recording channels as compared with the number of said seismic detector groups said method comprising: initiating data acquisition with a first group of alternating detectors, including one of said detector groups and each alternate detector group along at least a portion of the length of said seismic spread, being connected to the recording channels of said recorder; generating successive seismic waves with said seismic source at locations spaced at selected integral multiples of one half of the spacing between the centers of said detector groups; cyclically connecting an appropriate subset corresponding to the selected integral multiple of the alternating detector groups to said recording channels between each seismic wave generation, there being at least one unconnected detector group intervening between adjacent groups of alternating detectors in a subset; and recording electrical impulses transmitted by the selected detector groups connected to said recording channels responsive to seismic waves returned from subsurface earth strata.

Claim 2

A method of seismic exploration wherein a seismic source, and a plurality of equally spaced seismic detector groups are advanced along a traverse in a fixed horizontal relationship, seismic data recording means being provided and including a lesser number of recording channels as compared with the number of said seismic detector groups said method comprising: initiating data acquisition with a first group of alternating detectors, including one of said detector groups and each alternate detector group along at least a portion of the length of said seismic spread, being connected to the recording channels of said recorder; generating successive seismic waves with said seismic source at locations spaced at selected integral multiples of one half of the spacing between the centers of said detector groups; cyclically connecting an appropriate subset corresponding to the selected integral multiple of the alternating detector groups to said recording channels between each seismic wave generation, there being at least one unconnected detector group intervening between adjacent groups of alternating detectors in a subset; and recording electrical impulses transmitted by the selected detector groups connected to said recording channels responsive to seismic waves returned from subsurface earth strata.

Claim 10

A method of seismic exploration wherein a seismic source, and a plurality of equally spaced seismic detector groups are advanced along a traverse in a fixed horizontal relationship, seismic data recording means being provided and including a lesser number of recording channels as compared with the number of said seismic detector groups said method comprising: generating successive seismic waves with said seismic source at locations spaced at selected integral multiples of one-half the spacing between the centers of said detector groups; initiating data acquisition with a first group of said detectors including the second one of said detector groups and each successive even numbered detector group along the length of said seismic spread being connected to the recording channels of said recorder; switching said recording channels to a second group of said detectors including the first one of said detector groups and each successive odd numbered detector groups along the length of said seismic spread following the first seismic wave generation; and continuing cyclic switching of said recording channels between said first and second groups of said alternate detector groups following each seismic wave generation.

Claim 11

A method of seismic exploration wherein a seismic source, and a plurality of equally spaced seismic detector groups are advanced along a traverse in a fixed horizontal relationship, seismic data recording means being provided and including a lesser number of recording channels as compared with the number of said seismic detector groups said method comprising: generating successive seismic waves with said seismic source at locations spaced at selected integral multiples of one-half the spacing between the centers of said detector groups; initiating data acquisition with a first group of said detectors including the second one of said detector groups and each successive even numbered detector group along the length of said seismic spread being connected to the recording channels of said recorder; switching said recording channels to a second group of said detectors including the first one of said detector groups and each successive odd numbered detector groups along the length of said seismic spread following the first seismic wave generation; and continuing cyclic switching of said recording channels between said first and second groups of said alternate detector groups following each seismic wave generation.

Claim 12

A method of marine seismic exploration wherein a seismic spread having a plurality of seismic detector groups evenly spaced along the length thereof is towed through a body of water by a vessel, seismic data recording means being provided and including substantially one-half as many recording channels as compared with the number of said seismic detector groups, said method comprising: initiating data acquisition with a group of alternating detectors, including one of said detector groups and each alternate detector group along at least a portion of the length of said seismic spread, being connected to the recording channels of said recorder; towing said seismic spread through the body of water at an optimum constant speed for efficient data acquisition; generating successive seismic waves at spaced intervals in said body of water at shotpoint lOcations spaced at integral multiples of one-half the spacing between said detector groups of seismic spread as said seismic spread is towed through said body of water; switching said recording channels to alternate detector groups of said seismic spread in a direction opposed to the direction said seismic spread is being towed following each seismic wave generation; and recording electrical impulses transmitted to said recording channels by selected detector groups that are electrically connected to said recording channels.

Claim 13

A method of marine seismic exploration wherein a seismic spread having a plurality of seismic detector groups evenly spaced along the length thereof is towed through a body of water by a vessel, seismic data recording means being provided and including substantially one-half as many recording channels as compared with the number of said seismic detector groups, said method comprising: initiating data acquisition with a group of alternating detectors, including one of said detector groups and each alternate detector group along at least a portion of the length of said seismic spread, being connected to the recording channels of said recorder; towing said seismic spread through the body of water at an optimum constant speed for efficient data acquisition; generating successive seismic waves at spaced intervals in said body of water at shotpoint lOcations spaced at integral multiples of one-half the spacing between said detector groups of seismic spread as said seismic spread is towed through said body of water; switching said recording channels to alternate detector groups of said seismic spread in a direction opposed to the direction said seismic spread is being towed following each seismic wave generation; and recording electrical impulses transmitted to said recording channels by selected detector groups that are electrically connected to said recording channels.

Claim 17

A method of seismic exploration wherein a seismic spread is utilized having detector groups evenly spaced therealong and seismic data recording means is provided having a lesser number of recording channels than the number of said detector groups, said method comprising: initiating data acquisition with a first group of alternating detectors, including one of said detector groups and each alternate detector group along at least a portion of the length of said seismic spread, being connected to the recording channels of said recorder; locating said seismic spread at successive shotpoint positions along a traverse; generating seismic waves at each shotpoint position, said shotpoint positions being specifically located relative to said seismic spread; cyclicly switching said recording channels in a repetitive sequence a number of detector intervals corresponding to the number of half detector intervals between each shotpoint location to establish electrical connection with appropriate selected ones of said detector groups; and recording electrical impulses generated by each of said selected detector groups responsive to seismic waves reflected from subsurface earth strata.

Claim 18

A method of seismic exploration wherein a seismic spread is utilized having detector groups evenly spaced therealong and seismic data recording means is provided having a lesser number of recording channels than the number of said detector groups, said method comprising: initiating data acquisition with a first group of alternating detectors, including one of said detector groups and each alternate detector group along at least a portion of the length of said seismic spread, being connected to the recording channels of said recorder; locating said seismic spread at successive shotpoint positions along a traverse; generating seismic waves at each shotpoint position, said shotpoint positions being specifically located relative to said seismic spread; cyclicly switching said recording channels in a repetitive sequence a number of detector intervals corresponding to the number of half detector intervals between each shotpoint location to establish electrical connection with appropriate selected ones of said detector groups; and recording electrical impulses generated by each of said selected detector groups responsive to seismic waves reflected from subsurface earth strata.

Claim 20

A method of seismic exploration wherein a seismic spread is utilized having detector groups evenly spaced therealong and seismic data recording means is provided having a lesser number of recording channels than the number of said detector groups, said method comprising: locating said seismic spread at successive shotpoint positions along a traverse; generating seismic waves at each shotpoint position, said shotpoint positions being specifically located relative to said seismic spread; switching said recording channels between each shotpoint location to establish electrical connection with evenly spaced selected ones of said detector groups; recording electrical impulses generated by said selected detector groups responsive to seismic waves reflected from subsurface earth strata; said shotpoints are spaced along said traverse at a distance equal to one-half of the distance between the detector groups of said seismic spread; and said recording channels are connected with the even numbered ones of said detector groups at the beginning of said exploration and are switched alternatively between even and odd numbered detector groups between each shotpoint location.

Claim 21

A method of seismic exploration wherein a seismic spread is utilized having detector groups evenly spaced therealong and seismic data recording means is provided having a lesser number of recording channels than the number of said detector groups, said method comprising: locating said seismic spread at successive shotpoint positions along a traverse; generating seismic waves at each shotpoint position, said shotpoint positions being specifically located relative to said seismic spread; switching said recording channels between each shotpoint location to establish electrical connection with evenly spaced selected ones of said detector groups; recording electrical impulses generated by said selected detector groups responsive to seismic waves reflected from subsurface earth strata; said shotpoints are spaced along said traverse at a distance equal to one-half of the distance between the detector groups of said seismic spread; and said recording channels are connected with the even numbered ones of said detector groups at the beginning of said exploration and are switched alternatively between even and odd numbered detector groups between each shotpoint location.

Claim 22

A method of seismic exploration wherein a seismic spread is utilized having plurality of seismic detector groups evenly spaced along the seismic spread and seismic data recording means is provided having a lesser number of recording channels than the number of said detector groups, said method comprising: initIating data acquisition with a first group of alternating detectors, including one of said detector groups and each alternate detector group along at least a portion of the length of said seismic spread, being electrically connected to the recording channels of said recorder; locating said seismic spread at first positions along a traverse; generating successive seismic waves at shotpoints specifically located with respect to said seismic detector groups; recording electrical impulses generated by said first group of alternate detector groups responsive to seismic waves reflected from subsurface earth strata; relocating said seismic detector groups at second positions along said traverse, said second positions being spaced at selected integral multiples of one-half detector interval from said first positions; electrically disconnecting said first group of alternate seismic detector groups from said recording channels of said recording means; connecting a second group of alternate seismic detector groups corresponding to the selected integral multiples to said recording channels of said recording means; recording electrical impulses generated by reflected seismic waves generated at said shotpoints and received by said second group of alternate detector groups responsive to seismic waves reflected from subsurface earth strata; and continuing repetitively and in a predetermined sequence said relocation of said detector groups, generation of seismic waves and recording of electrical impulses from selected ones of said groups of said detector groups.

Claim 23

A method of seismic exploration wherein a seismic spread is utilized having plurality of seismic detector groups evenly spaced along the seismic spread and seismic data recording means is provided having a lesser number of recording channels than the number of said detector groups, said method comprising: initIating data acquisition with a first group of alternating detectors, including one of said detector groups and each alternate detector group along at least a portion of the length of said seismic spread, being electrically connected to the recording channels of said recorder; locating said seismic spread at first positions along a traverse; generating successive seismic waves at shotpoints specifically located with respect to said seismic detector groups; recording electrical impulses generated by said first group of alternate detector groups responsive to seismic waves reflected from subsurface earth strata; relocating said seismic detector groups at second positions along said traverse, said second positions being spaced at selected integral multiples of one-half detector interval from said first positions; electrically disconnecting said first group of alternate seismic detector groups from said recording channels of said recording means; connecting a second group of alternate seismic detector groups corresponding to the selected integral multiples to said recording channels of said recording means; recording electrical impulses generated by reflected seismic waves generated at said shotpoints and received by said second group of alternate detector groups responsive to seismic waves reflected from subsurface earth strata; and continuing repetitively and in a predetermined sequence said relocation of said detector groups, generation of seismic waves and recording of electrical impulses from selected ones of said groups of said detector groups.

Claim 24

A method of seismic exploration wherein a seismic spread is provided having a plurality of seismic detector groups evenly spaced along the length thereof, seismic data recording means being provided and including a lesser number of recording channels as compared with the number of said seismic detector groups, said method comprising: initiating data acquisition with a first group of alternating detectors, including one of said detector groups and each alternate detector group along at least a portion of the length of said seismic spread, being connected to the recording channels of said recorder; generating successive seismic waves at shotpoints specifically located relative to said detector groups of said seismic spread and spaced along a traverse at a predetermined distance equal to one-half of the spacing of said detector groups or any integral multiple of said distance; advancing the active location of said seismic spread a distance equal to the distance between said shotpoints between each seismic wave generation; successively connecting selected groups of said alternating detectors to said recording channels of said recorder between each seismic wave generation; and recording electrical impulses transmitted by the selected groups of detectors responsive to seismic waves reflected from subsurface earth strata.

Claim 25

A method of seismic exploration wherein a seismic spread is provided having a plurality of seismic detector groups evenly spaced along the length thereof, seismic data recording means being provided and including a lesser number of recording channels as compared with the number of said seismic detector groups, said method comprising: initiating data acquisition with a first group of alternating detectors, including one of said detector groups and each alternate detector group along at least a portion of the length of said seismic spread, being connected to the recording channels of said recorder; generating successive seismic waves at shotpoints specifically located relative to said detector groups of said seismic spread and spaced along a traverse at a predetermined distance equal to one-half of the spacing of said detector groups or any integral multiple of said distance; advancing the active location of said seismic spread a distance equal to the distance between said shotpoints between each seismic wave generation; successively connecting selected groups of said alternating detectors to said recording channels of said recorder between each seismic wave generation; and recording electrical impulses transmitted by the selected groups of detectors responsive to seismic waves reflected from subsurface earth strata.

Claim 26

A method of multiple fold seismic exploration wherein the spacing of subsurface observation points is maintained at a predetermined desired interval of distance independent of the number of fold of subsurface observation points, in which a seismic spread is provided having a plurality of seismic detector groups with centers evenly spaced at distance x and the number of said detector groups is equal to the number of desired fold of subsurface observation points, a seismic recording means being provided using a lesser number n of recording channels than the number of seismic detector groups and wherein the ratio of the number of detector groups to the number of recording channels is an integer m greater than one, a cyclical switch being provided to select the sequence of detector groups to be connected to the recording channels said method comprising: moving the seismic source and the seismic spread an incremental distance x/2 along the traverse; connecting a selected sequence of said detector groups to said recording channels wHerein the set of selectable sequences of detector groups is defined by: ( (w)th, (m+w)th, (2m+w)th, - - - , ( (n-1)m+w)th ) wherein the members of each sequence refer to the position of the selected seismic detector groups relative to the total spread of detector groups which is considered consecutively ordered with the first seismic detector group identified as that one which leads the spread in the direction of the traverse and w is a cycle index equal to 1, 2, 3 - - - , (m); advancing the cycle index w at each increment of x/2; generating seismic waves as integral multiples of x/2 and recording the electrical impulses transmitted by the selected sequence of detector groups responsive to seismic waves returned from subsurface earth strata.

Claim 27

A method of multiple fold seismic exploration wherein the spacing of subsurface observation points is maintained at a predetermined desired interval of distance independent of the number of fold of subsurface observation points, in which a seismic spread is provided having a plurality of seismic detector groups with centers evenly spaced at distance x and the number of said detector groups is equal to the number of desired fold of subsurface observation points, a seismic recording means being provided using a lesser number n of recording channels than the number of seismic detector groups and wherein the ratio of the number of detector groups to the number of recording channels is an integer m greater than one, a cyclical switch being provided to select the sequence of detector groups to be connected to the recording channels said method comprising: moving the seismic source and the seismic spread an incremental distance x/2 along the traverse; connecting a selected sequence of said detector groups to said recording channels wHerein the set of selectable sequences of detector groups is defined by: ( (w)th, (m+w)th, (2m+w)th, - - - , ( (n-1)m+w)th ) wherein the members of each sequence refer to the position of the selected seismic detector groups relative to the total spread of detector groups which is considered consecutively ordered with the first seismic detector group identified as that one which leads the spread in the direction of the traverse and w is a cycle index equal to 1, 2, 3 - - - , (m); advancing the cycle index w at each increment of x/2; generating seismic waves as integral multiples of x/2 and recording the electrical impulses transmitted by the selected sequence of detector groups responsive to seismic waves returned from subsurface earth strata.

Claim 28

A method of seismic exploration utilizing in combination a seismic source, a seismic spread of equally spaced seismic dtector groups, seismic data recording means with a lesser number of recording channels than the number of seismic detector groups, and a switching unit which progressively connects the said recording channels to selected, regularly alternating sequences of said seismic detector groups thus dividing the seismic spread into a series of sub-groups each corresponding to one of said seismic data recording channels; said switching unit having a number of positions corresponding to the number of seismic detector groups in each sub-group and which successively connects each of the seismic data recording channels to corresponding ones of each associated sub-group of seismic detector groups in cyclic manner, said method comprising: advancing the seismic source and the seismic spread along a traverse in a fixed horizontal relationship; cyclically actuating said switching unit in synchronism with the movement of the seismic source and seismic spread along the traverse at intervals equal to integral multiples of one-half the spacing between the centers of adjacent seismic detector groups so that each seismic data recording channel is successively connected to corresponding ones of its associated sub-group of seismic detector groups in inverse succession with respect to the direction of movement along the traverse; successively generating seismic waves with said seismic source at locations spaced at selected integral multiples of one-half the spacing between the centers of adjacent seismic detector groups; recording the electrical impulses produced by the selected seismic detector groups in response to each seismic wave generation with the seismic data recording means; cyclically repeating the switching, generation, and recording steps after all of the seismic detector groups of each sub-group have been successively connected to their associated seismic data recording channels in turn as the movement along the traverse is continued.

Claim 29

A method of seismic exploration utilizing in combination a seismic source, a seismic spread of equally spaced seismic dtector groups, seismic data recording means with a lesser number of recording channels than the number of seismic detector groups, and a switching unit which progressively connects the said recording channels to selected, regularly alternating sequences of said seismic detector groups thus dividing the seismic spread into a series of sub-groups each corresponding to one of said seismic data recording channels; said switching unit having a number of positions corresponding to the number of seismic detector groups in each sub-group and which successively connects each of the seismic data recording channels to corresponding ones of each associated sub-group of seismic detector groups in cyclic manner, said method comprising: advancing the seismic source and the seismic spread along a traverse in a fixed horizontal relationship; cyclically actuating said switching unit in synchronism with the movement of the seismic source and seismic spread along the traverse at intervals equal to integral multiples of one-half the spacing between the centers of adjacent seismic detector groups so that each seismic data recording channel is successively connected to corresponding ones of its associated sub-group of seismic detector groups in inverse succession with respect to the direction of movement along the traverse; successively generating seismic waves with said seismic source at locations spaced at selected integral multiples of one-half the spacing between the centers of adjacent seismic detector groups; recording the electrical impulses produced by the selected seismic detector groups in response to each seismic wave generation with the seismic data recording means; cyclically repeating the switching, generation, and recording steps after all of the seismic detector groups of each sub-group have been successively connected to their associated seismic data recording channels in turn as the movement along the traverse is continued.