CN112285782B - Near-surface seismic wave absorption attenuation investigation method and device - Google Patents
Near-surface seismic wave absorption attenuation investigation method and device Download PDFInfo
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- CN112285782B CN112285782B CN202011222762.8A CN202011222762A CN112285782B CN 112285782 B CN112285782 B CN 112285782B CN 202011222762 A CN202011222762 A CN 202011222762A CN 112285782 B CN112285782 B CN 112285782B
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- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/40—Seismology; Seismic or acoustic prospecting or detecting specially adapted for well-logging
- G01V1/44—Seismology; Seismic or acoustic prospecting or detecting specially adapted for well-logging using generators and receivers in the same well
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- G01V2210/61—Analysis by combining or comparing a seismic data set with other data
- G01V2210/616—Data from specific type of measurement
- G01V2210/6169—Data from specific type of measurement using well-logging
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Abstract
The invention discloses a near-surface seismic wave absorption attenuation investigation method and a near-surface seismic wave absorption attenuation investigation device, wherein the method comprises the following steps: acquiring a waveform of first arrival waves detected by detectors arranged at the wellhead and the bottom of each receiving well respectively; determining a zero point position with an amplitude value of 0 between the negative waveform and the positive waveform; the zero point position is taken as a symmetrical center, a central symmetrical waveform of the negative waveform is determined, and the negative waveform and the central symmetrical waveform are taken as new first arrival waveforms; combining the detector distance and the first arrival time of the two detectors, respectively carrying out spectrum analysis on new first arrival waveforms formed by detecting first arrival waves at the wellhead and the bottom of the well, and determining an actual Q value corresponding to the low speed reduction layer thickness between the positions of the two detectors; and determining a relation curve of the low deceleration layer thickness and the Q value according to the low deceleration layer thickness and the actual Q value at all absorption attenuation check points. The invention can eliminate the influence of near-surface ghost reflection and improve the accuracy and representativeness of absorption attenuation investigation.
Description
Technical Field
The invention relates to the technical field of geophysical exploration, in particular to a near-surface seismic wave absorption attenuation investigation method and device.
Background
This section is intended to provide a background or context to the embodiments of the invention that are recited in the claims. The description herein is not admitted to be prior art by inclusion in this section.
The absorption and attenuation of the near-surface low-speed-reducing layer to the seismic waves is one of important factors affecting the quality of the seismic data, and the near-surface absorption and attenuation investigation is an important means for obtaining the Q values of different near-surface low-speed-reducing layers and completing near-surface Q value compensation processing based on the Q values, so that the quality of the seismic data is improved. At present, two methods of double-well micro-logging absorption attenuation investigation and honeycomb micro-logging absorption attenuation investigation are mainly adopted for near-surface absorption attenuation investigation.
In the dual-well micro-logging absorption attenuation investigation, as shown in fig. 1, one well is a receiving well, the other well is an exciting well, a plurality of receiving points and a plurality of exciting points are respectively distributed in the receiving well and the exciting well from the surface to the high-speed top down at equal intervals or unequal intervals, the embedding depth of each receiving point is used for representing different low-speed layer thicknesses, and for any exciting point in the exciting well, each receiving point of the receiving well receives and forms common shot point gather data at the same time. When the same excitation point is excited, the positions of different receiving points are different, the arrival time of the received first arrival wave and the first arrival wave waveform are different, one first arrival wave is intercepted, calculation and analysis are carried out by combining the arrival time of the first arrival wave, the absorption attenuation Q value can be obtained, and the absorption attenuation Q value with different thicknesses can be obtained after statistics is carried out on a plurality of excitation points. The dual-well micro-logging absorption attenuation investigation cost is low, but the difficulty of good coupling between the borehole detector and the surrounding rock is high, and the real condition of the near-surface absorption attenuation Q value cannot be truly reflected due to the influence of the virtual reflection of the surface on the near-surface embedded detector.
The honeycomb micro-well logging absorption attenuation investigation is improved on the basis of the double-well micro-well logging absorption attenuation investigation. As shown in fig. 2, the excitation point is still in one excitation well, a plurality of receiving wells are distributed on the circumference of a certain radius by taking the excitation well as the center of a circle, the depth of each receiving well represents the thickness of a corresponding low-speed-reducing layer, and a detector is arranged at the bottom of each receiving well, so that the coupling between the receiving detector and surrounding rock is ensured. The honeycomb micro-logging absorption attenuation investigation has few abnormal points, but has high cost, small implementation amount and poor representativeness of a work area due to the honeycomb micro-logging absorption attenuation investigation, and the influence of the virtual reflection of the surface on the near-surface embedded detector is not eliminated yet.
Along with the application and development of an anti-Q compensation technology for seismic exploration data processing, the precision requirement on near-surface absorption attenuation Q value investigation is higher and higher. How to eliminate the influence of near-surface ghost reflection and improve the absorption attenuation investigation precision and representativeness becomes a technical problem which needs to be solved at present.
Disclosure of Invention
The embodiment of the invention provides a near-surface seismic wave absorption attenuation investigation method, which is used for eliminating the influence of near-surface ghost and improving the absorption attenuation investigation precision and representativeness, and comprises the following steps:
acquiring one waveform of a first arrival wave detected by a detector arranged at the wellhead and the bottom of each receiving well respectively, wherein one waveform of the first arrival wave comprises a negative waveform and a positive waveform, absorption attenuation check points are distributed on a two-dimensional absorption attenuation check line at equal intervals, and each absorption attenuation check point is provided with a receiving well and an excitation well;
determining a zero point position with an amplitude value of 0 between the negative waveform and the positive waveform;
the zero point position is taken as a symmetrical center, a central symmetrical waveform of the negative waveform is determined, and the negative waveform and the central symmetrical waveform are taken as new first arrival waveforms;
performing spectrum analysis on a new first-arrival waveform formed by the first-arrival wave detected by the wellhead by combining the distance between the two detectors and the first-arrival time received by the wellhead detector, performing spectrum analysis on the new first-arrival waveform formed by the first-arrival wave detected by the bottom of the well by combining the distance between the two detectors and the first-arrival time received by the bottom detector, and determining an actual Q value corresponding to a low-speed-reduction layer thickness between the positions of the two detectors;
and determining a relation curve of the low deceleration layer thickness and the Q value according to the low deceleration layer thickness and the actual Q value at all absorption attenuation check points.
The embodiment of the invention also provides a near-surface seismic wave absorption attenuation investigation device, which is used for eliminating the influence of near-surface ghost and improving the absorption attenuation investigation precision and representativeness, and comprises the following steps:
the acquisition module is used for acquiring one waveform of the first arrival wave detected by the detectors arranged at the wellhead and the bottom of each receiving well respectively, wherein one waveform of the first arrival wave comprises a negative waveform and a positive waveform, absorption attenuation check points are distributed on a two-dimensional absorption attenuation check line at equal intervals, and each absorption attenuation check point is provided with a receiving well and an excitation well;
the determining module is used for determining the zero point position with the amplitude value of 0 between the negative waveform and the positive waveform;
the determining module is also used for determining a central symmetrical waveform of the negative waveform by taking the zero point position as a symmetrical center, and taking the negative waveform and the central symmetrical waveform as new first arrival waveforms;
the determining module is also used for carrying out spectrum analysis on a new first-arrival waveform formed by the first-arrival wave detected by the wellhead by combining the detector distances of the two detectors and the first-arrival time received by the wellhead detector, carrying out spectrum analysis on the new first-arrival waveform formed by the first-arrival wave detected by the bottom hole by combining the detector distances of the two detectors and the first-arrival time received by the bottom hole detector, and determining an actual Q value corresponding to the low-speed-reduction layer thickness between the positions of the two detectors;
and the determining module is also used for determining a relation curve of the low deceleration layer thickness and the Q value according to the low deceleration layer thickness and the actual Q value at all absorption attenuation check points.
The embodiment of the invention also provides computer equipment, which comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the processor realizes the near-surface seismic wave absorption attenuation investigation method when executing the computer program.
The embodiment of the invention also provides a computer readable storage medium which stores a computer program for executing the near-surface seismic wave absorption attenuation investigation method.
In the embodiment of the invention, a plurality of absorption attenuation investigation points are distributed on a two-dimensional absorption attenuation investigation line at equal intervals, an excitation well and a receiving well are arranged at each investigation point, a detector is respectively arranged at the well head and the well bottom of the receiving well, the first arrival waveforms received by the well head and the well bottom detector are taken as negative waveforms, a new first arrival waveform is obtained by taking the negative waveforms as the basis, the actual Q values of different low-speed layer thicknesses are calculated, and finally, a relation curve of the low-speed layer thickness and the actual Q values is obtained. The detector is not embedded between the wellhead and the bottom of the well, so that the coupling problem of a plurality of detectors in the well and surrounding rock and the problem that the detectors arranged near the surface of the well are affected by surface ghosting are solved, the accuracy of Q value calculation and the reliability of the relation curve of the thickness of the low-speed-reducing layer and the Q value are improved, and a foundation is laid for subsequent Q compensation processing.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. In the drawings:
FIG. 1 is a schematic diagram of a prior art dual-well microlog absorption decay survey;
FIG. 2 is a schematic diagram of a prior art absorption decay survey of a honeycomb micro-log;
FIG. 3 is a flow chart of a near-surface seismic wave absorption attenuation survey method in an embodiment of the invention;
FIG. 4 is a schematic diagram of distribution of absorption/attenuation survey points on a two-dimensional absorption/attenuation survey line according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of synthesizing a new first arrival waveform based on a first arrival negative waveform according to an embodiment of the present invention;
FIG. 6 is a graph showing the distribution of the thickness and Q of the low-deceleration layer obtained by using the full original first-arrival waveform according to the embodiment of the present invention;
FIG. 7 is a graph showing the distribution of the thickness and Q of the low deceleration layer obtained by using the new first arrival waveform according to the embodiment of the present invention;
FIG. 8 is a schematic structural diagram of a near-surface seismic wave absorption attenuation survey device in an embodiment of the invention;
fig. 9 is a schematic structural diagram of a computer device according to an embodiment of the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention will be described in further detail with reference to the accompanying drawings. The exemplary embodiments of the present invention and their descriptions herein are for the purpose of explaining the present invention, but are not to be construed as limiting the invention.
The embodiment of the invention provides a near-surface seismic wave absorption attenuation investigation method, which needs to carry out the following preparation before realizing the method:
(1) Laying multiple absorption attenuation check points
Specifically, a typical position needing to perform absorption attenuation investigation is selected in a target work area, one or more sections of two-dimensional absorption attenuation investigation lines can be selected according to investigation targets, and a plurality of absorption attenuation investigation points are continuously distributed at equal intervals on each section of two-dimensional absorption attenuation investigation lines.
The absorption attenuation investigation points are required to be distributed according to the previous surface layer investigation results of the target work area, so that the absorption attenuation investigation points with certain quantity are distributed in different low-speed reduction layer thicknesses, and the reliability of the investigation result statistical effect is improved.
(2) Layout detector and excitation point
Each absorption decay survey point is surveyed by adopting a double-well micro-logging mode. Referring to fig. 4,1 well is used as a receiving well, and detectors are placed at the bottom of the well and at the top of the well (the surface), and two detectors are placed in total (the triangle represents the detector in fig. 4). The surface detectors are required to be placed flush with the surface, and in order to avoid the influence of the high-speed top interface, the bottom hole detectors are required to be placed about 1m above the high-speed top interface. The influence of the surface ghost reflection on near-surface receiving in the well can be avoided by not arranging the detector between the surface and the bottom of the well. The 1 well is used as an excitation well, the receiving amplitude of the bottom hole detector is not overrun, and the excitation position is more than 20m away from the bottom hole detector.
(3) Backfilling and sealing well by using broken surrounding rock
The bottom hole detector and the wellhead detector are both arranged in a thin long plastic shell, such as an explosive shell, and surrounding rock fragments are filled in the shell, and the long plastic shell can ensure that the bottom hole detector is in a vertical state. After the bottom hole detector is placed, backfilling surrounding rock fragments drilled by drilling into the well, fixing the bottom hole detector by using the surrounding rock fragments, and ensuring good coupling between the detector and the surrounding rock and enabling the medium state around the detector to be close to the original state of the surrounding rock as much as possible. The wellhead detector is also arranged in the explosive shell and embedded on the ground surface, so that the state of the detector is consistent with that of the detector at the bottom of the well as much as possible while the detector is flush with the ground surface.
(4) Acquisition of first arrival waves using high dynamic range seismic instrumentation
After the detectors and the excitation points of each absorption attenuation check point are distributed, a high dynamic range seismic instrument is adopted for acquisition, and the minimum sampling interval and the minimum forward gain of the seismic instrument are generally adopted. The instrument recording time length is determined according to the surface survey results and is generally set to be more than 200ms longer than the expected surface receiving time.
After the preparation is completed, the embodiment of the invention provides a near-surface seismic wave absorption attenuation investigation method, as shown in fig. 3, which comprises steps 301 to 305:
The number of the sampling points contained in the negative waveform is set as n, the amplitude value x and the sampling time t of the n sampling points are firstly obtained, and the amplitude value and the sampling time are formed (t n ，x n ) Is a set of the data sets. Wherein x is n For the sampling time t n Amplitude value of time sample point, from x 1 To x n All are less than or equal to 0.
If the last sample of the negative waveform sample, i.e. the nth sample, has an amplitude value x n Equal to 0, the nth sample point is determined as the zero point position.
If the amplitude value x of the nth sample point n If not equal to 0, the amplitude value x of the next sample (i.e. the (n+1) th sample) of the nth sample is set n+1 For 0, the (n+1) th sample is determined as the zero point position.
Due to the difference in zero point positions, the determination of the new first arrival waveform is divided into the following two cases:
(1) When the zero point position is the nth sample point
In x n Is symmetrical about a center of symmetry, pair (t n-1 ，x n-1 ) The array is folded up and down symmetrically to form (t 'of n-1 sample points' m ，x′ m ) An array, wherein m ranges from n+1 to n+n, where x 'is' m And x n Regarding t n Symmetrical and x' m And 0 or less.
Handle (t' m ，x′ m ) The array is folded left and right by taking the zero line as a symmetrical line to form an array (t) of n-1 sample points m ，x″ m ) Wherein m ranges from n+1 to n+n, in which case there is x' m ＝-x″ m ，x″ m And 0 or more.
At this time array (t) n ，x n )、(t″ m ，x″ m ) Fitting to form a new first arrival waveform based on the negative waveform of the first arrival waveform, based on (t n ，x n ) The sampling point is a center pair of symmetry centersCalled graphics.
(2) When the zero point position is the (n+1) th sample point
In x n+1 Is symmetrical about a center of symmetry, pair (t n ，x n ) The array is folded up and down symmetrically to form (t 'of n sample points' m ，x′ m ) An array, wherein m ranges from n+2 to n+n+1, where x' m And x n Regarding t n+1 Symmetrical, and x' m And 0 or less.
Handle (t' m ，x′ m ) The array is folded left and right by taking the zero line as a symmetrical line to form an array (t) of n sample points m ，x″ m ) Wherein m is in the range of n+2 to n+n+1, in which case there is x' m ＝-x″ m ，x″ m And 0 or more.
At this time array (t) n ，x n )、(t n+1 ，x n+1 )、(t″ m ，x″ m ) Fitting to form a new first arrival waveform based on the negative waveform of the first arrival waveform (t) n+1 ，x n+1 ) The sampling points are the center symmetrical graph of the symmetrical points.
The spectrum analysis can adopt a centroid frequency method or a spectrum ratio method, and the specific implementation of the spectrum analysis is not described herein because the spectrum analysis is a common technical means in the field of earth seismic exploration.
And 305, determining a relation curve of the low deceleration layer thickness and the Q value according to the low deceleration layer thickness and the actual Q value at all absorption attenuation check points.
Specifically, the actual Q values corresponding to the low-deceleration layer thicknesses of all the absorption attenuation check points are determined according to the methods from step 301 to step 304; performing curve fitting on all the obtained actual Q values and the low deceleration layer thickness by using a least square method to determine a fitting function; calculating theoretical Q values corresponding to the thicknesses of different low-speed-reduction layers according to the fitting function, and subtracting the actual Q values of the thicknesses of the same low-speed-reduction layers from the theoretical Q values to obtain deviation values of the thicknesses of the different low-speed-reduction layers; iteratively removing abnormal points based on the Laida criterion by utilizing the deviation value; fitting is carried out by using the thickness of the low deceleration layer after abnormal points are removed and the corresponding actual Q value, and a relation curve of the thickness of the low deceleration layer and the actual Q value is obtained.
The least square fitting may be an exponential fitting or a polynomial fitting, and typically an exponential fitting is used. The method is characterized in that abnormal points are removed based on the Laida criterion, a least square method is used for fitting a curve, and a fitting function is determined to be a common prior art, and detailed description of the specific implementation of the process is omitted.
In the embodiment of the invention, a plurality of absorption attenuation investigation points are distributed on a two-dimensional absorption attenuation investigation line at equal intervals, an excitation well and a receiving well are arranged at each investigation point, a detector is respectively arranged at the well head and the well bottom of the receiving well, the first arrival waveforms received by the well head and the well bottom detector are taken as negative waveforms, a new first arrival waveform is obtained by taking the negative waveforms as the basis, the actual Q values of different low-speed layer thicknesses are calculated, and finally, a relation curve of the low-speed layer thickness and the actual Q values is obtained. The detector is not embedded between the wellhead and the bottom of the well, so that the coupling problem of a plurality of detectors in the well and surrounding rock and the problem that the detectors arranged near the surface of the well are affected by surface ghosting are solved, the accuracy of Q value calculation and the reliability of the relation curve of the thickness of the low-speed-reducing layer and the Q value are improved, and a foundation is laid for subsequent Q compensation processing.
According to a certain three-dimensional seismic exploration acquisition project constructed in a large desert area in a Tarim basin tower, a two-dimensional absorption attenuation investigation line with a plurality of points with different low-speed-down layer thicknesses is laid for the surface characteristics of the three-dimensional seismic exploration acquisition project, a receiving mode of placing detectors on the ground surface and a wellhead is adopted to synthesize a first arrival wave negative waveform to form a new waveform, calculation is carried out, and finally, a relation curve of the low-speed-down layer thickness and the absorption attenuation Q value of the area is obtained, so that the three-dimensional seismic exploration acquisition line has better representativeness and avoids the influence of ground surface ghost on the Q value result, and has the following specific implementation conditions:
1) A plurality of absorption attenuation check points are arranged continuously in a line mode
In a large desert work area in the tower, a sand hill with typical work area characteristics is selected for absorption attenuation investigation according to the previous surface layer investigation result of the work area, the width of the sand hill is 3km, and the thickness of the low-speed reduction layer is distributed from 8m to 65 m. A two-dimensional absorption attenuation investigation line crossing the surface low-speed layer of the sand dune is distributed at intervals of 25m, 140 points are distributed in total, and a quantity basis is laid for fitting the thickness of the subsequent low-speed layer and the corresponding absorption attenuation Q value.
Fig. 4 is a schematic diagram of point location distribution and construction of the two-dimensional absorption attenuation investigation line, and the investigation result can be more representative by adopting continuous and multi-point arrangement of absorption attenuation investigation points.
2) Each absorption attenuation check point adopts a double-well micro-logging mode to arrange detectors and excitation points
Each absorption decay survey point is surveyed by adopting a double-well micro-logging mode. And 1 well is used as a receiving well, detectors are respectively arranged at the bottom of the well and the ground surface, and two detectors are arranged at the bottom of the well. The surface detectors are required to be placed flush with the surface, and in order to avoid the influence of the high-speed top interface, the bottom hole detectors are required to be placed about 1m above the high-speed top interface. The influence of the surface ghost reflection on near-surface receiving in the well can be avoided by not arranging the detector between the surface and the bottom of the well. The 1 well is used as an excitation well, the receiving amplitude of the bottom hole detector is not overrun, and the excitation position is more than 20m away from the bottom hole detector.
3) Backfilling and sealing well by using broken surrounding rock
The bottom hole detector and the wellhead detector are both arranged in a thin explosive shell, dry sand is filled in the shell, and the long explosive shell can ensure that the bottom hole detector is in a vertical state. After the bottom hole detector is placed, the bottom hole detector is backfilled into the well by dry fine sand, so that the coupling between the detector and surrounding rock is ensured to be good, and the state of medium around the detector is as close to the original state of the surrounding rock as possible. The wellhead detector is also arranged in the explosive shell and embedded on the ground surface, so that the state of the detector is consistent with that of the detector at the bottom of the well as much as possible while the detector is flush with the ground surface.
4) Acquisition with high dynamic range seismic instrumentation
After the detectors and the excitation points of each absorption attenuation check point are distributed, a high dynamic range seismic instrument is adopted for acquisition, a G3i seismic instrument is adopted this time, the sampling interval is 0.25ms, and the front gain is 0dB. The recording time length of the instrument is determined according to the surface survey result, and is generally more than 200ms plus the estimated surface receiving time, and the recording length is 1s.
5) Reducing the actual Q value of the single absorption attenuation check point affected by the surface ghost
And respectively intercepting a first arrival waveform from the seismic waves received by the two detectors for surface receiving and bottom hole receiving. Unlike conventional analysis, the first arrival waveform is then taken out to form a negative waveform portion, as shown in FIG. 5, where n number of negative waveform containing samples are provided, each negative waveform sample corresponds to a sampling time value, to form (t n ，x n ) Wherein x is n For time t n Amplitude value of time sample point, and from x 1 To x n And 0 or less.
A) When x is n When=0, x is n Is a symmetrical point pair (t n-1 ，x n-1 ) The array is folded up and down symmetrically to form (t 'of n-1 sample points' m ，x′ m ) An array, wherein m ranges from n+1 to n+n, where x 'is' m And x n Regarding t n Symmetrical and x' m And 0 or less.
Handle (t' m ，x′ m ) The array is folded left and right by taking the zero line as a symmetrical line to form an array (t 1) m ，x＂ m ) Wherein m is in the range of n+1 to n+n, in which case there is x' m ＝-x＂ m ，x＂ m And 0 or more.
At this time array (t) n ，x n )、(t＂ m ，x＂ m ) Forming a new waveform based on the first arrival negative waveform (t) n ，x n ) The sampling points are the center symmetrical graph of the symmetrical points.
B) When x is n If not equal to 0, setT is fixed n+1 Time x n+1 =0, and x n+1 Is a symmetrical point pair (t n ，x n ) The array is folded up and down symmetrically to form (t 'of n sample points' m ，x′ m ) An array, wherein m ranges from n+2 to n+n+1, where x' m And x n Regarding t n+1 Symmetrical and x' m And 0 or less.
Handle (t' m ，x′ m ) The array is folded right and left by taking the zero line as a symmetrical line to form an array (t 1) m ，x＂ m ) Wherein m is in the range of n+2 to n+n+1, in which case there is x' m ＝-x＂ m ，x＂ m And 0 or more.
At this time array (t) n ，x n )、(t n+1 ，x n+1 )、(t＂ m ，x＂ m ) Forming a new waveform based on the first arrival negative waveform (t) n+1 ，x n+1 ) The sampling points are the center symmetrical graph of the symmetrical points.
And knowing the distance and the first arrival time of two detectors of the earth surface reception and the bottom reception, performing spectrum analysis on new waveforms respectively formed by the earth surface reception and the bottom reception, and calculating the actual Q value corresponding to the thickness of the low-speed-reduction layer between the earth surface reception and the bottom reception by adopting a centroid frequency method.
And repeating the steps for all the absorption attenuation check points on the two-dimensional absorption attenuation check line, so that the actual Q value corresponding to the low-speed layer thickness of each absorption attenuation check point can be obtained.
6) Fitting thickness and Q value curves of different low-speed-reducing layer thicknesses of work area
And performing least square fitting on the thickness and Q value curves of the obtained actual Q values corresponding to the thicknesses of the different low-speed reduction layers, wherein exponential fitting or polynomial fitting can be adopted, and exponential fitting is generally adopted. And calculating theoretical Q values of different low-speed-reduction layer thicknesses according to the fitted formula, subtracting the theoretical Q values of the actual low-speed-reduction layer thicknesses from the Q values of the actual low-speed-reduction layer thicknesses to obtain deviations of different thicknesses, iteratively eliminating singular points based on Laida criteria, and finally fitting to obtain a relationship curve between the reasonable low-speed-reduction layer thicknesses and the actual Q values.
Fig. 6 is a graph showing the actual Q value calculated by using the full original first arrival waveform for different low deceleration layer thicknesses, and fig. 7 is a graph showing the actual Q value calculated by using the new first arrival waveform for different low deceleration layer thicknesses. From the comparison of the two graphs, the actual Q value distribution obtained by adopting the new first arrival waveform calculation is more concentrated and less in dispersion from the fitting line, the investigation result is more reasonable, and the fitting precision of the fitting curve is improved.
The embodiment of the invention also provides a near-surface seismic wave absorption attenuation investigation device, which is described in the following embodiment. Because the principle of the device for solving the problems is similar to that of the near-surface seismic wave absorption and attenuation investigation method, the implementation of the device can be referred to the implementation of the near-surface seismic wave absorption and attenuation investigation method, and the repetition is omitted.
As shown in fig. 8, the apparatus 800 includes an acquisition module 801 and a determination module 802.
The acquisition module 801 is configured to acquire one waveform of a first arrival wave detected by detectors respectively disposed at a wellhead and a bottom of each receiving well, where one waveform of the first arrival wave includes a negative waveform and a positive waveform, and absorption attenuation check points are disposed at equal intervals on a two-dimensional absorption attenuation survey line, and the receiving well and the excitation well are disposed at the absorption attenuation check points;
a determining module 802, configured to determine a zero position with an amplitude value of 0 between the negative waveform and the positive waveform;
the determining module 802 is further configured to determine a central symmetric waveform of the negative waveform by using the zero point position as a symmetric center, and use the negative waveform and the central symmetric waveform as new first arrival waveforms;
the determining module 802 is further configured to perform spectrum analysis on a new first-arrival waveform formed by the first-arrival wave detected at the wellhead by combining the detector distances of the two detectors and the first-arrival time received by the wellhead detector, perform spectrum analysis on the new first-arrival waveform formed by the first-arrival wave detected at the bottom of the well by combining the detector distances of the two detectors and the first-arrival time received by the bottom detector, and determine an actual Q value corresponding to a low-speed-reduction layer thickness between positions where the two detectors are located;
the determining module 802 is further configured to determine a relationship curve between the low deceleration layer thickness and the Q value according to the low deceleration layer thickness and the actual Q value at all absorption decay check points.
In one implementation of the embodiment of the present invention, a determining module 802 is configured to:
acquiring amplitude values and sampling time of all sampling points contained in the negative waveform;
if the amplitude value of the last sample point of the negative waveform sampling is equal to 0, determining the last sample point as a zero point position;
if the amplitude value of the last sample is not equal to 0, the amplitude value of the next sample of the last sample is set to 0, and the next sample is determined as a zero point position.
In one implementation of the embodiment of the present invention, a determining module 802 is configured to:
when the zero point position is the last sample point, other negative waveform sample points except the last sample point are used as symmetrical centers by taking the zero point position, and symmetrical sample points with central symmetry are determined;
when the zero position is the next sample point, taking the zero position of all the sample points of the negative waveform as the symmetry center, and determining symmetrical sample points with central symmetry;
and forming a central symmetrical waveform of the negative waveform by utilizing the symmetrical sample point fitting.
In one implementation mode of the embodiment of the invention, a detector of a wellhead is arranged at a position where the wellhead is flush with the ground surface, and the distance between the detector at the bottom of the well and a high-speed top interface is more than 1 meter; the excitation point in the excitation well is arranged below the high-speed top interface and is more than 20 meters away from the bottom hole detector.
In one implementation of the embodiment of the present invention, a determining module 802 is configured to:
determining the actual Q values corresponding to the low-speed-reduction layer thicknesses of all the absorption attenuation check points;
performing curve fitting on all the obtained actual Q values and the low deceleration layer thickness by using a least square method, and determining a fitting function;
calculating theoretical Q values corresponding to the thicknesses of different low-speed-reduction layers according to the fitting function, and subtracting the actual Q values of the thicknesses of the same low-speed-reduction layers from the theoretical Q values to obtain deviation values of the thicknesses of the different low-speed-reduction layers;
iteratively removing abnormal points based on the Laida criterion by utilizing the deviation value;
fitting is carried out by using the thickness of the low deceleration layer after abnormal points are removed and the corresponding actual Q value, and a relation curve of the thickness of the low deceleration layer and the actual Q value is obtained.
In the embodiment of the invention, a plurality of absorption attenuation investigation points are distributed on a two-dimensional absorption attenuation investigation line at equal intervals, an excitation well and a receiving well are arranged at each investigation point, a detector is respectively arranged at the well head and the well bottom of the receiving well, the first arrival waveforms received by the well head and the well bottom detector are taken as negative waveforms, a new first arrival waveform is obtained by taking the negative waveforms as the basis, the actual Q values of different low-speed layer thicknesses are calculated, and finally, a relation curve of the low-speed layer thickness and the actual Q values is obtained. The detector is not embedded between the wellhead and the bottom of the well, so that the coupling problem of a plurality of detectors in the well and surrounding rock and the problem that the detectors arranged near the surface of the well are affected by surface ghosting are solved, the accuracy of Q value calculation and the reliability of the relation curve of the thickness of the low-speed-reducing layer and the Q value are improved, and a foundation is laid for subsequent Q compensation processing.
The embodiment of the invention also provides a computer device, and fig. 9 is a schematic diagram of the computer device in the embodiment of the invention, where the computer device can implement all the steps in the near-surface seismic wave absorption attenuation investigation method in the embodiment, and the computer device specifically includes the following contents:
a processor (processor) 901, a memory (memory) 902, a communication interface (Communications Interface) 903, and a communication bus 904;
wherein the processor 901, the memory 902, and the communication interface 903 perform communication with each other through the communication bus 904; the communication interface 903 is used for implementing information transmission between related devices;
the processor 901 is configured to invoke a computer program in the memory 902, where the processor executes the computer program to implement the near-surface seismic wave absorption attenuation investigation method in the above embodiment.
The embodiment of the invention also provides a computer readable storage medium which stores a computer program for executing the near-surface seismic wave absorption attenuation investigation method.
It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the scope of the invention, but to limit the invention to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (12)
1. A method of near-surface seismic wave absorption attenuation investigation, the method comprising:
acquiring one waveform of a first arrival wave detected by a detector arranged at the wellhead and the bottom of each receiving well respectively, wherein one waveform of the first arrival wave comprises a negative waveform and a positive waveform, absorption attenuation check points are distributed on a two-dimensional absorption attenuation check line at equal intervals, and each absorption attenuation check point is provided with a receiving well and an excitation well;
determining a zero point position with an amplitude value of 0 between the negative waveform and the positive waveform;
the zero point position is taken as a symmetrical center, a central symmetrical waveform of the negative waveform is determined, and the negative waveform and the central symmetrical waveform are taken as new first arrival waveforms;
performing spectrum analysis on a new first-arrival waveform formed by the first-arrival wave detected by the wellhead by combining the distance between the two detectors and the first-arrival time received by the wellhead detector, performing spectrum analysis on the new first-arrival waveform formed by the first-arrival wave detected by the bottom of the well by combining the distance between the two detectors and the first-arrival time received by the bottom detector, and determining an actual Q value corresponding to a low-speed-reduction layer thickness between the positions of the two detectors;
and determining a relation curve of the low deceleration layer thickness and the Q value according to the low deceleration layer thickness and the actual Q value at all absorption attenuation check points.
2. The method of claim 1, wherein determining a zero position having an amplitude value of 0 between the negative waveform and the positive waveform comprises:
acquiring amplitude values and sampling time of all sampling points contained in the negative waveform;
if the amplitude value of the last sample point of the negative waveform sampling is equal to 0, determining the last sample point as a zero point position;
and if the amplitude value of the last sample point is not equal to 0, setting the amplitude value of the next sample point of the last sample point to be 0, and determining the next sample point as a zero point position.
3. The method of claim 2, wherein determining a center symmetric waveform of the negative waveform with the zero point position as a center of symmetry comprises:
when the zero point position is the last sample point, other negative waveform sample points except the last sample point are taken as symmetrical centers by taking the zero point position, and symmetrical sample points with central symmetry are determined;
when the zero position is the next sample point, taking the zero position of all the sample points of the negative waveform as the symmetry center, and determining symmetrical sample points with central symmetry;
and forming a central symmetrical waveform of the negative waveform by utilizing the symmetrical sample point fitting.
4. The method of claim 1, wherein the wellhead sonde is positioned flush with the surface of the well and the downhole sonde is more than 1 meter from the high speed top interface; the excitation point in the excitation well is arranged below the high-speed top interface and is more than 20 meters away from the bottom hole detector.
5. The method of claim 4, wherein determining a low deceleration layer thickness versus Q based on the low deceleration layer thickness versus actual Q at all absorption decay check points comprises:
determining the actual Q values corresponding to the low-speed-reduction layer thicknesses of all the absorption attenuation check points;
performing curve fitting on all the obtained actual Q values and the low deceleration layer thickness by using a least square method, and determining a fitting function;
calculating theoretical Q values corresponding to the thicknesses of different low-speed-reduction layers according to the fitting function, and subtracting the actual Q values of the thicknesses of the same low-speed-reduction layers from the theoretical Q values to obtain deviation values of the thicknesses of the different low-speed-reduction layers;
iteratively removing abnormal points based on a Laida criterion by utilizing the deviation value;
fitting is carried out by using the thickness of the low deceleration layer after abnormal points are removed and the corresponding actual Q value, and a relation curve of the thickness of the low deceleration layer and the actual Q value is obtained.
6. A near-surface seismic wave absorption attenuation survey apparatus, the apparatus comprising:
the acquisition module is used for acquiring one waveform of the first arrival wave detected by the detectors arranged at the wellhead and the bottom of each receiving well respectively, wherein one waveform of the first arrival wave comprises a negative waveform and a positive waveform, absorption attenuation check points are distributed on a two-dimensional absorption attenuation check line at equal intervals, and each absorption attenuation check point is provided with a receiving well and an excitation well;
the determining module is used for determining the zero point position with the amplitude value of 0 between the negative waveform and the positive waveform;
the determining module is also used for determining a central symmetrical waveform of the negative waveform by taking the zero point position as a symmetrical center, and taking the negative waveform and the central symmetrical waveform as new first arrival waveforms;
the determining module is also used for carrying out spectrum analysis on a new first-arrival waveform formed by the first-arrival wave detected by the wellhead by combining the detector distances of the two detectors and the first-arrival time received by the wellhead detector, carrying out spectrum analysis on the new first-arrival waveform formed by the first-arrival wave detected by the bottom hole by combining the detector distances of the two detectors and the first-arrival time received by the bottom hole detector, and determining an actual Q value corresponding to the low-speed-reduction layer thickness between the positions of the two detectors;
and the determining module is also used for determining a relation curve of the low deceleration layer thickness and the Q value according to the low deceleration layer thickness and the actual Q value at all absorption attenuation check points.
7. The apparatus of claim 6, wherein the determining module is configured to:
acquiring amplitude values and sampling time of all sampling points contained in the negative waveform;
if the amplitude value of the last sample point of the negative waveform sampling is equal to 0, determining the last sample point as a zero point position;
and if the amplitude value of the last sample point is not equal to 0, setting the amplitude value of the next sample point of the last sample point to be 0, and determining the next sample point as a zero point position.
8. The apparatus of claim 7, wherein the determining module is configured to:
when the zero point position is the last sample point, other negative waveform sample points except the last sample point are taken as symmetrical centers by taking the zero point position, and symmetrical sample points with central symmetry are determined;
when the zero position is the next sample point, taking the zero position of all the sample points of the negative waveform as the symmetry center, and determining symmetrical sample points with central symmetry;
and forming a central symmetrical waveform of the negative waveform by utilizing the symmetrical sample point fitting.
9. The apparatus of claim 6, wherein the wellhead pickup is positioned flush with the wellhead and the surface, and wherein the downhole pickup is more than 1 meter from the high-speed top interface; the excitation point in the excitation well is arranged below the high-speed top interface and is more than 20 meters away from the bottom hole detector.
10. The apparatus of claim 9, wherein the determining module is configured to:
determining the actual Q values corresponding to the low-speed-reduction layer thicknesses of all the absorption attenuation check points;
performing curve fitting on all the obtained actual Q values and the low deceleration layer thickness by using a least square method, and determining a fitting function;
calculating theoretical Q values corresponding to the thicknesses of different low-speed-reduction layers according to the fitting function, and subtracting the actual Q values of the thicknesses of the same low-speed-reduction layers from the theoretical Q values to obtain deviation values of the thicknesses of the different low-speed-reduction layers;
iteratively removing abnormal points based on a Laida criterion by utilizing the deviation value;
fitting is carried out by using the thickness of the low deceleration layer after abnormal points are removed and the corresponding actual Q value, and a relation curve of the thickness of the low deceleration layer and the actual Q value is obtained.
11. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the method of any of claims 1 to 5 when executing the computer program.
12. A computer readable storage medium, characterized in that the computer readable storage medium stores a computer program for executing the method of any one of claims 1 to 5.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4926392A (en) * | 1986-09-22 | 1990-05-15 | Hand Geophysical | Method and apparatus for obtaining seismic vibrator reflection data |
| US5105391A (en) * | 1990-10-31 | 1992-04-14 | Exxon Production Research Company | Method for high-resolution seismic recording using detectors planted at shallow depths |
| US5724308A (en) * | 1995-10-10 | 1998-03-03 | Western Atlas International, Inc. | Programmable acoustic borehole logging |
| CN102109617A (en) * | 2010-12-15 | 2011-06-29 | 大庆油田有限责任公司 | Method for measuring Q value of near surface strata by using twin-well microlog |
| CN104749634A (en) * | 2013-12-26 | 2015-07-01 | 中国石油化工股份有限公司 | Extremely-shallow layer absorption compensation method based on viscoelastic medium model |
| CN106443810A (en) * | 2016-05-10 | 2017-02-22 | 北京奥地探测仪器有限公司 | High-precision data conversion and acquisition system suitable for gravimeter |
| CN106990438A (en) * | 2017-03-28 | 2017-07-28 | 中国石油天然气集团公司 | Complicated earth surface region micro logging point position and well depth determine method and device |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| UA72581C2 (en) * | 2002-08-30 | 2005-03-15 | Method for investigating oil-and-gas deposits by seismic waves |
-
2020
- 2020-11-05 CN CN202011222762.8A patent/CN112285782B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4926392A (en) * | 1986-09-22 | 1990-05-15 | Hand Geophysical | Method and apparatus for obtaining seismic vibrator reflection data |
| US5105391A (en) * | 1990-10-31 | 1992-04-14 | Exxon Production Research Company | Method for high-resolution seismic recording using detectors planted at shallow depths |
| US5724308A (en) * | 1995-10-10 | 1998-03-03 | Western Atlas International, Inc. | Programmable acoustic borehole logging |
| CN102109617A (en) * | 2010-12-15 | 2011-06-29 | 大庆油田有限责任公司 | Method for measuring Q value of near surface strata by using twin-well microlog |
| CN104749634A (en) * | 2013-12-26 | 2015-07-01 | 中国石油化工股份有限公司 | Extremely-shallow layer absorption compensation method based on viscoelastic medium model |
| CN106443810A (en) * | 2016-05-10 | 2017-02-22 | 北京奥地探测仪器有限公司 | High-precision data conversion and acquisition system suitable for gravimeter |
| CN106990438A (en) * | 2017-03-28 | 2017-07-28 | 中国石油天然气集团公司 | Complicated earth surface region micro logging point position and well depth determine method and device |
Non-Patent Citations (3)
| Title |
|---|
| Wang Yanfeng et al..The choice of bin size based on the imaging accuracy of fractured-cavity reservoirs in carbonate rocks.2018 CPS/SEG International Geophysical Conference.2018,全文. * |
| 周翼等.塔克拉玛干沙漠区浅表层对地震波的吸收衰减作用.石油地球物理勘探.2016,第51卷(第51期),全文. * |
| 赵秋芳等.近地表Ｑ 值测试方法研究进展与展望.《石油地球物理勘探》.2019,第第54卷卷(第第54卷期),全文. * |
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