Summary of the invention
It is an object of the invention to solve problem present in existing smooth floating datum selecting technology, by establishing simultaneouslySmooth floating datum cost functional is minimized, realizes the quantitative calculation method of datum level, passes through the longitudinal minimum imaging point of earthquakeThe limitation of resolution λ/4 determines maximum smoothing factor and minimum smoothing factor, so that the selection of smooth floating datum hasQuantitative, reliable foundation provides basis for subsequent velocity analysis and migration imaging processing.
According to an aspect of the present invention, a kind of quantitative choosing side of smooth floating datum in seismic data process is providedMethod, this method comprises:
It establishes and minimizes smooth floating datum cost functional；
Determine maximum smoothing factor；
Determine minimum smoothing factor；
The arbitrary value between maximum smoothing factor and minimum smoothing factor is selected, smooth floating datum is sought.
Further, smooth floating datum cost functional is minimized to be expressed as follows:
Wherein, h indicates true earth's surface elevation, hsIndicate smooth floating datum, the right first part is light in formula (1)Sliding floating datum and real surface approach item, and Section 2, Section 3 are respectively smooth floating datum x, the second order in the direction yPartial derivative, αxAnd αyThe smoothing factor in the direction referred to as x, y, Dxx, DyyIndicate the matrix that second-order partial differential coefficient is constituted.
Further, to hsDerivation is carried out, and enabling it is zero, obtains following result:
Wherein, I is unit matrix.
Further, according to maximum high frequency static correction value and near-surface velocity, the highest elevation correcting value of permission is calculatedmax(h-hs), so that it is determined that maximum smoothing factor α, makes the elevation correction amount of all geophone stations of earth's surface be both less than highest elevation schoolPositive quantity.
Further, the high frequency static correction value of inspection point indicates are as follows:
Wherein, Δ Tshot_recFor the high frequency static correction value in current seismic road, Vs(x)shotFor smooth earth's surface shot point speed, Vs(x)recFor smooth earth's surface geophone station speed, h (x)shotShot point real surface elevation, hs(x)shotThe smooth earth's surface elevation of shot point, h(x)recGeophone station real surface elevation, hs(x)recThe smooth earth's surface elevation of geophone station.
Further, it is required according to the interpolation of travel time field to determine minimum smoothing factor, so that the travelling that interpolation obtainsWhen and real surface calculate travelling when difference be no more than T/4.
Further, the arbitrary value between maximum smoothing factor and minimum smoothing factor is selected, (3) formula of utilization is sought smoothFloating datum hs。
According to another aspect of the present invention, a kind of quantitative choosing system of smooth floating datum in seismic data process is providedSystem, the system include:
Memory is stored with computer executable instructions；
Processor, the processor run the computer executable instructions in the memory, execute following steps:
It establishes and minimizes smooth floating datum cost functional；
Determine maximum smoothing factor；
Determine minimum smoothing factor；
The arbitrary value between maximum smoothing factor and minimum smoothing factor is selected, smooth floating datum is sought.
Further, maximum smoothing factor and minimum light are determined by the limitation of longitudinal minimum imaging resolution λ/4 of earthquakeThe sliding factor.
Further, smooth floating datum h is sought using formula (3)s:
Wherein, h indicates true earth's surface elevation, hsIndicate smooth floating datum, αxAnd αyThe direction referred to as x, y it is smoothThe factor, Dxx, DyyIndicate that the matrix that second-order partial differential coefficient is constituted, I are unit matrix.
The quantitative choosing technology of smooth floating datum in the seismic data process, first according to the smooth floating base of minimumQuasi- Area Objects functional realizes the quantitative expression of smooth floating datum, then according to longitudinal minimum imaging resolution λ/4 of earthquakeLimitation determines maximum smoothing factor and minimum smoothing factor, provides any light between maximum smoothing factor and minimum smoothing factorThe sliding factor can find out the correcting value that each pair of point is answered on smooth floating datum.
Compared with prior art, The present invention gives the quantization formulas of smooth floating datum building, so that smoothThe building of floating datum is more scientific.In addition, The present invention gives the smoothing factor selection gist of smooth floating datum withAnd the range of choice determined, keep the selection of smooth floating datum more reasonable.Therefore, algorithm of the invention is scientific, it is real to be easy toExisting, computational efficiency is high.
Specific embodiment
The preferred embodiment of the disclosure is more fully described below with reference to accompanying drawings.Although showing the disclosure in attached drawingPreferred embodiment, however, it is to be appreciated that may be realized in various forms the disclosure without the embodiment party that should be illustrated hereFormula is limited.On the contrary, these embodiments are provided so that this disclosure will be more thorough and complete, and can be by the disclosureRange is completely communicated to those skilled in the art.
The present invention selects problem for existing smooth floating datum quantification, by establishing and minimizing smooth floating baseQuasi- Area Objects functional provides a kind of quantitative calculation method of smooth floating datum, and passes through the longitudinal minimum imaging point of earthquakeThe limitation of resolution λ/4 determines maximum smoothing factor and minimum smoothing factor, between maximum smoothing factor and minimum smoothing factorThe correcting value that each pair of point is answered on smooth floating datum can be found out by providing any smoothing factor, so that smooth floating referenceThe selection in face has quantitative, reliable foundation so that the building of smooth floating datum is more scientific, be subsequent velocity analysis andMigration imaging processing provides basis.
As shown in Figure 1, providing a kind of quantifying for smooth floating datum in seismic data process the present disclosure proposes a kind ofSelection method, this method comprises:
It establishes and minimizes smooth floating datum cost functional；
Determine maximum smoothing factor；
Determine minimum smoothing factor；
The arbitrary value between maximum smoothing factor and minimum smoothing factor is selected, smooth floating datum is sought.
Method of the invention is directed to the quantitative choosing problem of smooth datum level, establishes smooth floating datum cost functional,The quantitative expression of smooth floating datum is obtained, and then maximum is determined according to the limitation of longitudinal minimum imaging resolution λ/4 of earthquakeSmoothing factor and minimum smoothing factor, providing any smoothing factor between maximum smoothing factor and minimum smoothing factor can find outThe correcting value that each pair of point is answered on smooth floating datum.
Specifically, it the described method comprises the following steps:
(1) it establishes and minimizes smooth floating datum cost functional.
Assuming that h indicates true earth's surface elevation, obtained smooth floating datum hs, it is desirable to hsMeet two itemsPart: first is that with real surface as close as, second is that will smooth as far as possible namely second-order partial differential coefficient it is small as far as possible,Second-order partial differential coefficient can pass through matrix Dxx, DyyIt indicates.The above problem can be by minimizing following smooth floating datum cost functionalTo realize:
Wherein, in formula (1) the right first part be smooth floating datum and real surface the item that approaches, Section 2, theThree are respectively smooth floating datum x, the second-order partial differential coefficient in the direction y, αxAnd αyThe smoothing factor in the direction referred to as x, y, generally takesαx=αy=α, α is bigger, datum level hsSmooth degree is higher.
In order to solve above-mentioned functional minimum, need to hsDerivation is carried out, and enabling it is zero, obtains following result:
To obtain:
(3) formula is typical system of linear equations, can pass through the general solutions such as conjugate gradient method, least square proper orthogonal decompositionDirect solution, at this time αxAnd αyAs regularization term, it is added with unit matrix I, it is practical just to play smooth effect, αxAnd αySmooth degree is represented, the floating datum after obtained result namely smoothing.
(2) maximum smoothing factor is determined
The determination of maximum smoothing factor is from the angle analysis of migration imaging longitudinal resolution, and the selection of smoothing factor is former at this timeBe then due to smooth floating datum and the reflection wave height wave number TEC time error correction that is introduced into does not influence to be imaged the same of back wave in trace gatherIt is superimposed, i.e., do not change the accurate location and imaging energy of migration imaging.In seismic prospecting, seismic imaging it is longitudinal minimum atPicture resolution ratio is λ/4, and λ is the corresponding wavelength of seismic wave dominant frequency, and it is quiet to obtain back wave maximum according to longitudinal minimum imaging resolutionCorrecting value is necessarily less than T/4, and T is the seismic wave dominant frequency corresponding period, that is, meets following relational expression:
ΔTshot_rec<T/4 (4)
ΔTshot_recFor the high frequency static correction value of geophone station.At the x of any position real surface and smooth floating datum itBetween high frequency static correction value indicate are as follows:
Wherein, H (x) is weathering depth；V (x) is earth's surface true velocity；VsIt (x) is the smooth speed of earth's surface, actually earth's surfaceTrue velocity is unknown, therefore generally assumes that the near-surface model for chromatographing to establish by near surface is that accurately, that is, have V (x) ≈Vs(x).In this way, the high frequency static correction value of inspection point can indicate at this time are as follows:
Wherein, Δ Tshot_recFor the high frequency static correction value in current seismic road, Vs(x)shotFor smooth earth's surface shot point speed, Vs(x)recFor smooth earth's surface geophone station speed, h (x)shotShot point real surface elevation, hs(x)shotThe smooth earth's surface elevation of shot point, h(x)recGeophone station real surface elevation, hs(x)recThe smooth earth's surface elevation of geophone station.
The high frequency static correction value indicated in consideration formula (6) is not only related with near-surface velocity, also and caused by smoothing factorEarth's surface elevation correction difference is related, as near-surface velocity Vs(x) in the case where having determined, high frequency static correction value only with smooth floating referenceFace hsIt is related.
Highest elevation correcting value max (h-hs) be all shot points, geophone station corresponding real surface and smooth earth's surface differenceMaximum value.Different smoothing factor α generates different smooth earth's surface hs, the smooth earth's surface h of the bigger generation of smoothing factor αsMore lightIt is sliding, highest elevation correcting value max (h-hs) also bigger.It is available arbitrarily to bring the depth displacement of all inspection points into formula (6)Shake the high frequency static correction value Δ T in roadshot_rec, guarantee that the high frequency static correction value is equal to the smooth datum level h of T/4sIt is corresponding smoothThe factor is maximum smoothing factor.
(3) minimum smoothing factor is determined
The determination of minimum smoothing factor requires to determine from the interpolation of travel time field.For the inclined of Kirchhoff integral classShifting method needs to carry out before being deviated the calculating of control point travel time field, and travel time field at this time is in plane spaceIt is generally differed to hundreds of meters for tens meters at interval.When deviating trace gather, need to insert respectively when the travelling according to control pointValue calculates the travel time field of shot point and geophone station.Specifically interpolation can be carried out by the position of control point travel time field and shot point geophone stationObtain, which is generally linear interpolation, if interpolation obtain travelling when and real surface calculate travelling when difference be more thanT/4, then when needing to carry out real surface the travelling for smoothly interpolation being obtained of minimum smoothing factor and truly meterThe difference when travelling of calculation is no more than T/4.
Part elevation schematic diagram, A when 200 meters of control point interval when Fig. 4 is travelling1A2Dotted line is Linear Curve,B1B2B3B4B5For true earth's surface elevation curve, A1B'2A2For smooth floating reference surface curve.A1, A2To calculate control when travellingThe elevation location of point, B1, B2, B3, B4, B5Interpolation point when for calculative travelling.With B2It is analyzed for point, if B2It arrivesThe depth displacement B of Linear Curve2B”2Caused TEC time error correction amount is not above T/4, illustrates that the local elevation variation rate of exchange are gentle,It can not have to carry out the smooth of minimum smoothing factor, i.e., minimum smoothing factor is zero.If B2To the elevation of Linear CurvePoor B2B”2Caused TEC time error correction amount has been more than T/4, then B2It there is biggish error by the travel time field that interpolation obtains,And then the in-phase stacking of lineups is influenced, at this time with regard to needing smooth, the smooth knot to the minimum smoothing factor of local elevation progressFruit is by B2Point is moved to B'2Place guarantees B'2B”2Caused elevation TEC time error correction amount is no more than T/4, and depth displacement specifically calculatesMethod has so then obtained the selection method of minimum smoothing factor referring to (6) formula.
(4) calculating of smooth datum level
After maximum smoothing factor and minimum smoothing factor has been determined, may be selected maximum smoothing factor and minimum smoothing factor itBetween arbitrary value, and then utilize (3) formula seek smooth floating datum hs, complete the calculating of smooth datum level.
Another embodiment according to the present invention provides a kind of quantitative choosing of smooth floating datum in seismic data processSystem is selected, which includes:
Memory is stored with computer executable instructions；
Processor, the processor run the computer executable instructions in the memory, execute following steps:
It establishes and minimizes smooth floating datum cost functional；
Determine maximum smoothing factor；
Determine minimum smoothing factor；
The arbitrary value between maximum smoothing factor and minimum smoothing factor is selected, smooth floating datum is sought.
Further, maximum smoothing factor and minimum light are determined by the limitation of longitudinal minimum imaging resolution λ/4 of earthquakeThe sliding factor.
Further, smooth floating datum h is sought using formula (3)s:
Wherein, h indicates true earth's surface elevation, hsIndicate smooth floating datum, αxAnd αyThe direction referred to as x, y it is smoothThe factor, Dxx, DyyIndicate that the matrix that second-order partial differential coefficient is constituted, I are unit matrix.
The present invention gives the quantization formulas of smooth floating datum building, so that the building of smooth floating datumIt is more scientific.In addition, The present invention gives the smoothing factor selection gist of smooth floating datum and the range of choice of determination,Keep the selection of smooth floating datum more reasonable.Therefore, algorithm of the invention is scientific, is easily achieved, and computational efficiency is high.
A concrete application example is given below in the scheme and its effect of the embodiment of the present invention for ease of understanding.This fieldIt should be understood to the one skilled in the art that the example is only for the purposes of understanding the present invention, any detail is not intended to be limited in any wayThe system present invention.
Fig. 2-Fig. 3 describes one embodiment of the present of invention, and Fig. 2 shows the smooth schematic diagrames of the elevation of different smoothing factors(vertical unit: rice, lateral position point), black solid line is original elevation in figure,Smooth earth's surface when for smoothing factor being 10Elevation,The smooth earth's surface elevation for being 25 for smoothing factor, it can be seen that smoothing factor is bigger, and earth's surface is more smooth.Fig. 3 showsTwo different corresponding elevation correction amount schematic diagrames of smoothing factor (vertical unit: rice, lateral position point) are gone out, in figureDepth displacement when for smoothing factor being 10,The depth displacement for being 25 for smoothing factor, smoothing factor smooth earth's surface when being 10Highest elevation correcting value is 40m, and the highest elevation correcting value of smooth earth's surface is 47m when smoothing factor is 25, it can be seen that withThe increase of smoothing factor, depth displacement are also bigger.Assuming that near-surface velocity is 1000m/s, the T/4 of seismic wave is 80ms, then itsThe highest elevation difference of permission is 40m, and smoothing factor 10 is maximum smoothing factor at this time.
Part elevation schematic diagram, A when 200 meters of control point interval when Fig. 4 is travelling1A2Dotted line is Linear Curve,B1B2B3B4B5For true earth's surface elevation curve, A1B'2A2For smooth floating reference surface curve.A1, A2To calculate control when travellingThe elevation location of point, B1, B2, B3, B4, B5Interpolation point when for calculative travelling.With B2It is analyzed for point, if B2It arrivesThe depth displacement B of Linear Curve2B”2Caused TEC time error correction amount is not above T/4, illustrates that the local elevation variation rate of exchange are gentle,It can not have to carry out the smooth of minimum smoothing factor, i.e., minimum smoothing factor is zero.If B2To the elevation of Linear CurvePoor B2B”2Caused TEC time error correction amount has been more than T/4, then B2It there is biggish error by the travel time field that interpolation obtains,And then the in-phase stacking of lineups is influenced, at this time with regard to needing smooth, the smooth knot to the minimum smoothing factor of local elevation progressFruit is by B2Point is moved to B'2Place guarantees B'2B”2Caused elevation TEC time error correction amount is no more than T/4, and depth displacement specifically calculatesMethod has so then obtained the selection method of minimum smoothing factor referring to (6) formula.
The presently disclosed embodiments is described above, above description is exemplary, and non-exclusive, andIt is not limited to disclosed each embodiment.Without departing from the scope and spirit of illustrated each embodiment, for this skillMany modifications and changes are obvious for the those of ordinary skill in art field.The selection of term used herein, purportIn principle, the practical application or to the technological improvement in market for best explaining each embodiment, or make the art itsIts those of ordinary skill can understand each embodiment disclosed herein.