Separation and noise removal for multiple vibratory source seismic data
First Claim
1. A method for separating multiple-vibrator seismic data and reducing separation-related noise, said seismic data being recorded in an actual or simulated survey with N vibrators (N>
- 1) operating simultaneously, with the number of sweeps per vibrator being fewer than N and the sweeps for each vibrator being different from the sweeps for the other vibrators in some manner, a sweep being defined as a period of continuous source energy radiation terminated by a listening time or other cessation of vibration for a time period at least as long as the two-way travel time of a seismic wave traveling from a vibrator down to a pre-selected deepest target of interest and back up to a seismic receiver, said method comprising;
(a) separating the survey data to obtain a preliminary estimate of N seismograms, one per vibrator; and
(b) adjusting the seismograms to match the survey data and to satisfy selected characteristics of noise-free seismograms, thereby producing N updated seismograms;
wherein said adjusting comprises extracting that part of each seismogram that corresponds to signal, and using the extracted signal parts to generate an updated set of separated seismograms; and
wherein the set of updated seismograms is generated by convolving each extracted signal part with its corresponding vibrator signature, then stacking all N results, subtracting that from the survey data, separating the result of that by vibrator, and for each vibrator adding that to the corresponding extracted signal part.
0 Assignments
0 Petitions
Accused Products
Abstract
The invention discloses a way to recover separated seismograms with reduced interference noise by processing vibroseis data recorded (or computer simulated) with multiple vibrators shaking simultaneously or nearly simultaneously (200). A preliminary estimate of the separated seismograms is used to obtain improved seismograms (201). The preliminary estimate is convolved with the vibrator signature and then used to update the seismogram. Primary criteria for performing the update include fitting the field data and satisfying typical criteria of noise-free seismograms (202). Alternative ways to update are disclosed, including signal extraction, modeled noise extraction, constrained optimization based separation, and penalized least-squares based separation. The method is particularly suited for removing noise caused by separating the combined record into separate records for each vibrator, and is advantageous where the number of sweeps is fewer than the number of vibrators (200).
51 Citations
22 Claims
-
1. A method for separating multiple-vibrator seismic data and reducing separation-related noise, said seismic data being recorded in an actual or simulated survey with N vibrators (N>
- 1) operating simultaneously, with the number of sweeps per vibrator being fewer than N and the sweeps for each vibrator being different from the sweeps for the other vibrators in some manner, a sweep being defined as a period of continuous source energy radiation terminated by a listening time or other cessation of vibration for a time period at least as long as the two-way travel time of a seismic wave traveling from a vibrator down to a pre-selected deepest target of interest and back up to a seismic receiver, said method comprising;
(a) separating the survey data to obtain a preliminary estimate of N seismograms, one per vibrator; and (b) adjusting the seismograms to match the survey data and to satisfy selected characteristics of noise-free seismograms, thereby producing N updated seismograms;
wherein said adjusting comprises extracting that part of each seismogram that corresponds to signal, and using the extracted signal parts to generate an updated set of separated seismograms; and
wherein the set of updated seismograms is generated by convolving each extracted signal part with its corresponding vibrator signature, then stacking all N results, subtracting that from the survey data, separating the result of that by vibrator, and for each vibrator adding that to the corresponding extracted signal part. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
- 1) operating simultaneously, with the number of sweeps per vibrator being fewer than N and the sweeps for each vibrator being different from the sweeps for the other vibrators in some manner, a sweep being defined as a period of continuous source energy radiation terminated by a listening time or other cessation of vibration for a time period at least as long as the two-way travel time of a seismic wave traveling from a vibrator down to a pre-selected deepest target of interest and back up to a seismic receiver, said method comprising;
-
14. A method for separating multiple-vibrator seismic data and reducing separation-related noise, said seismic data being recorded in an actual or simulated survey with N vibrators (N>
- 1) operating simultaneously, with the number of sweeps per vibrator being fewer than N and the sweeps for each vibrator being different from the sweeps for the other vibrators in some manner, a sweep being defined as a period of continuous source energy radiation terminated by a listening time or other cessation of vibration for a time period at least as long as the two-way travel time of a seismic wave traveling from a vibrator down to a pre-selected deepest target of interest and back up to a seismic receiver, said method comprising;
(a) separating the survey data to obtain a preliminary estimate of N seismograms, one per vibrator; and (b) adjusting the seismograms to match the survey data and to satisfy selected characteristics of noise-free seismograms, thereby producing N updated seismograms;
wherein said adjusting comprises extracting parts of each seismogram, based on a model of the way in which noise is manifested in the survey data and using the extracted parts to generate an updated set of separated seismograms; and
wherein the set of updated seismograms is generated by convolving each extracted part with its corresponding vibrator signature, then stacking all N results, performing an operation on the stacked results, and subtracting that from the survey data, then separating the result of that by vibrator using the noise-reduced record to obtain improved separation of the seismograms. - View Dependent Claims (15, 16, 17)
- 1) operating simultaneously, with the number of sweeps per vibrator being fewer than N and the sweeps for each vibrator being different from the sweeps for the other vibrators in some manner, a sweep being defined as a period of continuous source energy radiation terminated by a listening time or other cessation of vibration for a time period at least as long as the two-way travel time of a seismic wave traveling from a vibrator down to a pre-selected deepest target of interest and back up to a seismic receiver, said method comprising;
-
18. A method for separating multiple-vibrator seismic data and reducing separation-related noise, said seismic data being recorded in an actual or simulated survey with N vibrators (N>
- 1) operating simultaneously, with the number of sweeps per vibrator being fewer than N and the sweeps for each vibrator being different from the sweeps for the other vibrators in some manner, a sweep being defined as a period of continuous source energy radiation terminated by a listening time or other cessation of vibration for a time period at least as long as the two-way travel time of a seismic wave traveling from a vibrator down to a pre-selected deepest target of interest and back up to a seismic receiver, said method comprising;
(a) separating the survey data to obtain a preliminary estimate of N seismograms, one per vibrator; and (b) adjusting the seismograms to match the survey data and to satisfy selected characteristics of noise-free seismograms, thereby producing N updated seismograms;
wherein the adjusting comprises using the preliminary estimate of the separated seismograms in conjunction with the survey data and each vibrator'"'"'s signature to determine an updated set of updated seismograms using constrained optimization theory. - View Dependent Claims (19, 20, 21, 22)
- 1) operating simultaneously, with the number of sweeps per vibrator being fewer than N and the sweeps for each vibrator being different from the sweeps for the other vibrators in some manner, a sweep being defined as a period of continuous source energy radiation terminated by a listening time or other cessation of vibration for a time period at least as long as the two-way travel time of a seismic wave traveling from a vibrator down to a pre-selected deepest target of interest and back up to a seismic receiver, said method comprising;
Specification