CN104181593B - Three-dimensional ray-free tracing contraflexure wave tomographic imaging method and device - Google Patents

Abstract

The invention relates to a three-dimensional ray-free tracing contraflexure wave tomographic imaging method and device. The three-dimensional ray-free tracing contraflexure wave tomographic imaging method comprises the steps that single-shot first arrivals are picked up, first arrivals at multiple azimuthal angles are selected according to an azimuthal angle interval among all the single-shot first arrivals, offset-distance progressive increase sequencing is carried out on the first arrivals at all the azimuthal angles, and therefore a first arrival curve within the range of 0-x is formed; low-order polynomial least square method global fitting is carried out on the first arrival curve within the range of 0-x with the offset distance as the horizontal coordinate and the first arrival time as the vertical coordinate, and multinomial coefficients corresponding to the azimuthal angle of each single-shot first arrival are obtained; an azimuthal angle slowness curve corresponding to each single-shot first arrival is obtained according to the corresponding multinomial coefficients; the velocity and depth of a contraflexure wave contraflexure point corresponding to the azimuthal angle selected by each single-shot first arrival which is picked up are obtained according to the corresponding azimuthal angle slowness curve of each single-shot first arrival; a three-dimensional velocity field is obtained through interpolation according to the velocity and depth of the contraflexure wave contraflexure point corresponding to the azimuthal angle selected by each single-shot first arrival which is picked up.

Description

A kind of three-dimensional without ray tracing diving Wave chromatography imaging method and device

Technical field

The present invention relates to seismic data processing technology field, chromatograph into without ray tracing diving Wave particularly to a kind of three-dimensional As method and device.

Background technology

In seismic data process, travel time tomography method is a kind of important velocity imaging method.Whilst on tour layer Analysis imaging can be divided into according to calculation process just drills whilst on tour, two key steps of inverting slowness.Just drill whilst on tour and include travelling Time calculate, generally also contain ray tracing.Whether ray tracing is carried out according to after just drilling whilst on tour, can be simply by whilst on tour layer Analysis imaging is divided into two class situations:

(1) traditional ray tracing travel time tomography method.This class method setting speed is distributed in discrete grid block joint On point, internodal bin speed is constant or gradual change.Grid after just drilling whilst on tour can use such as gradient method, interchange mathod Ask for ray path, thus obtain each point that receives and just drilling the error of whilst on tour and first break picking, be then iterated inverting more New velocity field.

Existing three-dimensional diving Wave tomography mainly uses traditional radiographic to follow the trail of travel time tomography method, the most about Shu Sudu is laterally invariant, and vertical gradual change is incremented by, thus meets the condition that diving Wave is propagated, and then iteration carries out three-dimensional ray tracing With inverting to update slowness.

This class method advantage be to underground VELOCITY DISTRIBUTION without any it is assumed that be adapted to arbitrarily complicated or simple speed ?.The computational methods of ray path are had higher requirements by the velocity field that shortcoming is complicated, need to process whilst on tour up to, ray burnt The challenges such as scattered, velocity gradient is discontinuous.It addition, ray path is generally curve so that inverting presents strong nonlinearity, solve Also there is multi-solution in difficulty.When contract speed the most vertically gradual change, the velocity field that ripple vertically gradual change is incremented by is with diving Wave Form is propagated and inflection is to earth's surface, obtains traditional diving Wave travel time tomography method.

(2) without ray tracing diving Wave travel time tomography method.The same contract speed of this class method is the most vertically Gradual change.But, according to the propagation law of diving Wave, can with the degree of depth of derivation formula analytical Calculation diving Wave inflection point and speed, Thus avoid complexity just drill whilst on tour and ray tracing, inverting updates slowness process.

Existing three-dimensional diving Wave tomography mainly uses without ray tracing diving Wave travel time tomography method, should Method is substantially a kind of two dimension algorithm, it is impossible to carry out 3D velocity field imaging.

To sum up, existing method is that the first arrival time to 3D seismic data carries out three-dimensional exploded (Osypov, 2000), then Whilst on tour application two dimension algorithm after decomposing is calculated.But the algorithm decomposed is complicated and needs successive ignition.

Summary of the invention

In order to solve problem of the prior art, the present invention proposes a kind of three-dimensional without ray tracing diving Wave chromatography imaging method And device, extension two dimension without ray tracing diving Wave chromatography imaging technique to D seismic data processing, it is to avoid the three of complexity Dimension whilst on tour Breaking Recurrently process.

For achieving the above object, the invention provides a kind of three-dimensional without ray tracing diving Wave chromatography imaging method, the party Method includes:

The single big gun first arrival of pickup, each single big gun first arrival to pickup is azimuthal according to the selected at least two in orientation angles interval First arrival, and each azimuth first arrival is sorted according to offset distance incremental manner, form the first arrival curve in the range of 0～x；Its In, x is maximum offset；

With offset distance as abscissa, first arrival time as vertical coordinate, the first arrival curve in the range of 0～x is carried out lower order polynomial Formula method of least square overall fit, obtains the azimuth multinomial coefficient accordingly of each single big gun first arrival；

The azimuth slowness curve of the most each single big gun first arrival is obtained according to described multinomial coefficient；

Azimuth slowness curve according to described each single big gun first arrival obtains the side that each single big gun first arrival of pickup is selected The speed of parallactic angle diving Wave inflection point accordingly and the degree of depth；

The speed of the azimuth diving Wave inflection point accordingly that each single big gun first arrival according to pickup is selected and the degree of depth are inserted It is worth into 3D velocity field.

Preferably, the speed of the azimuth diving Wave inflection point accordingly that each single big gun first arrival of described pickup is selected obtains Access method is:

The azimuth slowness curve of each single big gun first arrival of pickup is appointed in the range of 0～x that to take M point be diving Wave inflection Point；

Obtain the inverse of the slowness curve value of an i correspondence position, obtain the speed of an i；Wherein, i=1,2 ..., M.

Preferably, the degree of depth of the azimuth diving Wave inflection point accordingly that each single big gun first arrival of described pickup is selected obtains Access method is:

Integral formula is used to obtain the degree of depth of an i；Wherein, described integral formula is:

$z_i=\frac{1}{\mathrm{\π}}{\∫}_0^{x_i}\cos h^{-1}\left(\frac{\frac{\mathrm{dt}}{\mathrm{dx}}}{{\left(\frac{\mathrm{dt}}{\mathrm{dx}}\right)}_i}\right)\mathrm{dx}$

Wherein, z_iFor the degree of depth that inflection point i is corresponding, x_iFor the offset distance that an i is corresponding.

Preferably, the method that the azimuth slowness curve of described each single big gun first arrival obtains is:

Multinomial is obtained according to described multinomial coefficient；

Described multinomial is carried out derivation, it is thus achieved that the azimuth slowness curve of each single big gun first arrival.

Preferably, described orientation angles is spaced apart quite or unequal orientation angles interval.

For achieving the above object, present invention also offers a kind of three-dimensional without ray tracing diving Wave laminated imaging device, should Device includes:

First arrival curve acquisition unit, is used for picking up single big gun first arrival, to each single big gun first arrival of pickup according to orientation angles between Every the azimuthal first arrival of selected at least two, and to each azimuth first arrival according to offset distance incremental manner sort, formed 0～ First arrival curve in the range of x；Wherein, x is maximum offset；

Fitting unit, for offset distance as abscissa, first arrival time as vertical coordinate, to the first arrival curve in the range of 0～x Carry out lower order polynomial expressions method of least square overall fit, obtain the azimuth multinomial coefficient accordingly of each single big gun first arrival；

Azimuth slowness curve acquiring unit, for obtaining the most each single big gun first arrival according to described multinomial coefficient Azimuth slowness curve；

The speed of diving Wave inflection point and degree of depth acquiring unit, for the azimuth slowness according to described each single big gun first arrival Curve obtains speed and the degree of depth of the azimuth diving Wave inflection point accordingly that each single big gun first arrival picked up is selected；

Interpolating unit, for the azimuth diving Wave inflection point accordingly selected of each single big gun first arrival according to pickup Speed and the degree of depth are interpolated to 3D velocity field.

Preferably, speed and the degree of depth acquiring unit of described diving Wave inflection point includes: diving Wave inflection point acquisition module With the first computing module；Wherein,

Described diving Wave inflection point acquisition module, is used for the azimuth slowness curve to each single big gun first arrival picked up 0 ～in the range of x, appoint that to take M point be diving Wave inflection point；

Described first computing module, for obtaining the inverse of the slowness curve value of an i correspondence position, obtains the speed of an i； Wherein, i=1,2 ..., M.

Preferably, speed and the degree of depth acquiring unit of described diving Wave inflection point also includes the second computing module；Wherein,

Described second computing module, for using integral formula to obtain the degree of depth of an i；Wherein, described integral formula is:

$z_i=\frac{1}{\mathrm{\π}}{\∫}_0^{x_i}\cos h^{-1}\left(\frac{\frac{\mathrm{dt}}{\mathrm{dx}}}{{\left(\frac{\mathrm{dt}}{\mathrm{dx}}\right)}_i}\right)\mathrm{dx}$

Wherein, z_iFor the degree of depth that inflection point i is corresponding, x_iFor the offset distance that an i is corresponding.

Preferably, described azimuth slowness curve acquiring unit includes: multinomial acquisition module and derivation module；Wherein,

Described multinomial acquisition module, for obtaining multinomial according to described multinomial coefficient；

Described derivation module, for carrying out derivation to described multinomial, it is thus achieved that the azimuth slowness of each single big gun first arrival is bent Line.

Preferably, the orientation angles that described first arrival curve acquisition unit uses is spaced apart quite or unequal orientation angles Interval.

Technique scheme has the advantages that

By tradition without multiple along 3D seismic data of the diving Wave whilst on tour two dimension chromatography imaging method of ray tracing Azimuth carries out a point azimuth application, thus obtains three-dimensional computations result.The technical program avoids the three-dimensional whilst on tour of complexity Breaking Recurrently process, is thus susceptible to realize, and when selecting, azimuth number is less, such as, less than 40, calculate speed the most quickly.

Accompanying drawing explanation

In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing In having technology to describe, the required accompanying drawing used is briefly described, it should be apparent that, the accompanying drawing in describing below is only this Some embodiments of invention, for those of ordinary skill in the art, on the premise of not paying creative work, it is also possible to Other accompanying drawing is obtained according to these accompanying drawings.

Fig. 1 is that the one that the present invention proposes is three-dimensional without ray tracing diving Wave chromatography imaging method flow chart；

Fig. 2 is that the one that the present invention proposes is three-dimensional without ray tracing diving Wave laminated imaging device block diagram；

Fig. 3 is that the three-dimensional of the present embodiment is without ray tracing diving Wave chromatography imaging method flow chart；

Fig. 4 is the tomography design sketch of this enforcement.

Detailed description of the invention

Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete Describe, it is clear that described embodiment is only a part of embodiment of the present invention rather than whole embodiments wholely.Based on Embodiment in the present invention, it is every other that those of ordinary skill in the art are obtained under not making creative work premise Embodiment, broadly falls into the scope of protection of the invention.

The operation principle of the technical program is: the single big gun first arrival to two dimension is extracted, it is thus achieved that multiple azimuthal two dimensions Line, uses two dimension to calculate without ray tracing diving Wave travel time tomography algorithm, reaches according to the combination of angles of azimuth The effect of three-dimensional computations, it is to avoid complicated iteration three-dimensional whilst on tour decomposition computation.

As it is shown in figure 1, the one for present invention proposition is three-dimensional without ray tracing diving Wave chromatography imaging method flow chart.Should Method includes:

Step 101) the single big gun first arrival of pickup, each single big gun first arrival to pickup selectes at least two according to orientation angles interval Azimuthal first arrival, and each azimuth first arrival is sorted according to offset distance incremental manner, form the first arrival in the range of 0～x Curve；Wherein, x is maximum offset；

In step 101) in, described single big gun first break pickup is obtained by the way of automatic or mutual pickup by processing software , it is thus achieved that first arrival data in must be containing the azimuth information in this road.Single big gun first arrival data to pickup, according to equal or not Equal orientation angles interval, extracts multiple azimuthal first arrival, and each azimuthal first arrival is pressed the incremental row of offset distance Sequence, first arrival curve in the range of forming 0～x.

Each azimuth of single big gun first arrival, can be one, it is also possible to be multiple azimuths.During only one of which azimuth, The effect that equivalent two dimension chromatography calculates.When specifying multiple azimuth, can be by equal or unequal orientation angles interval, spirit Live and select the angle of needs.

Step 102) with offset distance as abscissa, first arrival time as vertical coordinate, the first arrival curve in the range of 0～x is carried out Lower order polynomial expressions method of least square overall fit, obtains the azimuth multinomial coefficient accordingly of each single big gun first arrival；

In step 102) in, described first arrival curve overall fit is based on selected list azimuthal first arrival curve: with skew Away from for abscissa, first arrival time is vertical coordinate, and the first arrival to 0～x scope carries out lower order polynomial expressions method of least square overall fit. Selecting to carry out with root of a polynomial weighted sum the multinomial of quick point during matching, such as Legnedre polynomial, Chebyshev is many Item formula.Multinomial low order below 5 rank, is generally selected 2 rank.The system of polynomials that first arrival data are corresponding is obtained after matching Number.

Step 103) according to described multinomial coefficient obtain the most each single big gun first arrival azimuth slowness curve；

In step 103) in, step 102) in multinomial coefficient obtain multinomial, described slowness curve is by multinomial Formula is differentiated and is obtained.Computational methods are: by step 102) the middle polynomial Derivative Formula calculated, derivative in the range of calculating 0～x The value of p=dt/dx, i.e. can get slowness curve.Wherein, t is first arrival time, and x is offset distance, and d is derivative operation symbol.Due to Slowness curve calculates and directly employs multinomial derivative formula, and therefore, it can be regularly arranged for calculating the coordinate used, it is possible to To be irregular alignment.

Step 104) obtain, according to the azimuth slowness curve of described each single big gun first arrival, each single big gun first arrival institute picked up The speed of selected azimuth diving Wave inflection point accordingly and the degree of depth；

In step 104) in, described speed calculation method is: to step 103) the designated parties parallactic angle slowness curve tried to achieve, In the range of 0～x, appoint and take M point, obtain the inverse 1/ (dt/dx) of the slowness curve value of an i position_i(i=1,2 ..., M), Obtain the speed of this inflection point.

In step 104) in, the degree of depth following integral formula of employing of some i:

$z_i=\frac{1}{\mathrm{\π}}{\∫}_0^{x_i}\cos h^{-1}\left(\frac{\frac{\mathrm{dt}}{\mathrm{dx}}}{{\left(\frac{\mathrm{dt}}{\mathrm{dx}}\right)}_i}\right)\mathrm{dx}$

Wherein, z_iFor the degree of depth that inflection point i is corresponding, x_iFor offset distance.Depth calculation is 0～x_iIn the range of, node-by-node algorithm Integral kernel function, then, to 0～x_iIntegration obtains z_i.Due to step 103) in multinomial have selected can with root of a polynomial weighting ask With carry out the multinomial of quick point, therefore integration uses Gauss integration to carry out quick point, for M integral and calculating point, can To obtain the polynomial accurate solution in 2M-1 rank.Due to step 102) in matching first arrival curve have employed lower order polynomial expressions, such as 2 rank, Therefore M can obtain the least, such as M=2, can obtain 3 rank multinomials and accurately solve.So the present invention is in inflection point depth calculation Time, not only integral accuracy is high, and integral and calculating amount is the least, and computational efficiency is high.

In step 104) calculate time, the M point coordinates chosen can be equidistant, it is also possible to unequal-interval.M point can cover All offset distance scopes, it is also possible to only cover a part of offset distance scope.

Step 105) speed of azimuth diving Wave inflection point accordingly selected according to each single big gun first arrival of pickup It is interpolated to 3D velocity field with the degree of depth.

As in figure 2 it is shown, the one for present invention proposition is three-dimensional without ray tracing diving Wave laminated imaging device block diagram.This dress Put and include:

First arrival curve acquisition unit 201, is used for picking up single big gun first arrival, to each single big gun first arrival picked up according to orientation angles The selected azimuthal first arrival of at least two in interval, and each azimuth first arrival is sorted according to offset distance incremental manner, form 0 ～the first arrival curve in the range of x；Wherein, x is maximum offset；

Fitting unit 202, for offset distance as abscissa, first arrival time as vertical coordinate, to the first arrival in the range of 0～x Curve carries out lower order polynomial expressions method of least square overall fit, obtains the azimuth system of polynomials accordingly of each single big gun first arrival Number；

Azimuth slowness curve acquiring unit 203, for obtaining at the beginning of the most each single big gun according to described multinomial coefficient Azimuth slowness curve extremely；

The speed of diving Wave inflection point and degree of depth acquiring unit 204, for the azimuth according to described each single big gun first arrival Slowness curve obtains speed and the degree of depth of the azimuth diving Wave inflection point accordingly that each single big gun first arrival picked up is selected；

Interpolating unit 205, for the azimuth diving Wave inflection accordingly selected according to each single big gun first arrival of pickup Speed and the degree of depth of point are interpolated to 3D velocity field.

Preferably, speed and the degree of depth acquiring unit 204 of described diving Wave inflection point includes: diving Wave inflection point obtains mould Block and the first computing module；Wherein,

Described diving Wave inflection point acquisition module, is used for the azimuth slowness curve to each single big gun first arrival picked up 0 ～in the range of x, appoint that to take M point be diving Wave inflection point；

Described first computing module, for obtaining the inverse of the slowness curve value of an i correspondence position, obtains the speed of an i； Wherein, i=1,2 ..., M.

Preferably, speed and the degree of depth acquiring unit 204 of described diving Wave inflection point also includes the second computing module；Its In,

Described second computing module, for using integral formula to obtain the degree of depth of an i；Wherein, described integral formula is:

$z_i=\frac{1}{\mathrm{\π}}{\∫}_0^{x_i}\cos h^{-1}\left(\frac{\frac{\mathrm{dt}}{\mathrm{dx}}}{{\left(\frac{\mathrm{dt}}{\mathrm{dx}}\right)}_i}\right)\mathrm{dx}$

Wherein, z_iFor the degree of depth that inflection point i is corresponding, x_iFor the offset distance that an i is corresponding.

Preferably, described azimuth slowness curve acquiring unit 203 includes: multinomial acquisition module and derivation module；Its In,

Described multinomial acquisition module, for obtaining multinomial according to described multinomial coefficient；

Described derivation module, for carrying out derivation to described multinomial, it is thus achieved that the azimuth slowness of each single big gun first arrival is bent Line.

Preferably, the orientation angles that described first arrival curve acquisition unit 201 uses is spaced apart quite or unequal orientation Angle is spaced.

In order to understand the present invention in depth, with application example, embodiments of the invention are made the most below in conjunction with the accompanying drawings Describe.

As it is shown on figure 3, be that the three-dimensional of the present embodiment is without ray tracing diving Wave chromatography imaging method flow chart.It is embodied as Mode is:

Step 1) the single big gun first arrival of pickup sorting by azimuth: first first break picking data, and foundation work area scope and big gun, Cautious earth's surface elevation, sets up Grid Velocity model, and initializing speed is 0.Single big gun first arrival to pickup, is sorted by azimuth, and First arrival after sorting is pressed offset distance sort ascending, and first arrival curve in the range of forming 0～3000 meter, wherein 3000 meters is selection Maximum offset.

Step 2) to specifying azimuthal first arrival curve to carry out overall fit: in single big gun, to specifying azimuthal first arrival, Using 2 rank Legnedre polynomials, with offset distance as abscissa, first arrival time is vertical coordinate, carries out method of least square overall fit, Solve the multinomial coefficient that this azimuth is corresponding.

Step 3) polynomial curve of designated parties parallactic angle matching is calculated slowness curve: utilize step 2) in obtain many Binomial coefficient, according to 2 rank Legnedre polynomial Derivative Formulas, with step 2) in offset distance as abscissa, calculate 0～3000 meter In the range of slowness curve p=dt/dx.

Step 4) calculate corresponding speed and the degree of depth of this azimuthal diving Wave inflection point: first, in 0～3000 scopes In, node-by-node algorithm step 3) inverse 1/ (dt/dx) of slowness curve p that obtains_i(i=1,2 ..., M), obtain i-th corresponding The speed of inflection point；Secondly, use 3 Gauss-Legendre's integrations, calculate the inflection point degree of depth of some i.Utilize depth calculation public Formula:

$z_i=\frac{1}{\mathrm{\π}}{\∫}_0^{x_i}\cos h^{-1}\left(\frac{\frac{\mathrm{dt}}{\mathrm{dx}}}{{\left(\frac{\mathrm{dt}}{\mathrm{dx}}\right)}_i}\right)\mathrm{dx}$

First to 0～i point pointwise differentiation value and divided by constant (dt/dx)_i, calculate cosh^-1Functional value；Secondly, number is looked into Learn to do volume and obtain 3 Gausses-Legnedre polynomial root and weight coefficient, 0～x_iAccurate integration is tried to achieve in scope weighted sum, calculates Go out inflection point degree of depth z_i。

Equidistant Nodes can be integrated by Gauss-Legendre's integration, it is also possible to is integrated Unequal distance node, therefore Taking originally the most corresponding offset distance is coordinates computed point, is adapted to the situation of the regularly arranged and irregular arrangement of geophone station.Meter Such as have only to partial offset away from calculating during calculation, then limit limit of integration.

Step 5) each azimuth to single big gun, repeat step 2)～step 4), obtain the corresponding inflection point degree of depth and right Answer speed: now select 36 azimuths, with 10 degree of equal intervals distributions.

Step 6) all single big guns are repeated step 2)～step 5), obtain whole inflection point degree of depth and corresponding speed.

Step 7) speed point is interpolated to 3D velocity field.

As shown in Figure 4, the tomography design sketch implemented for this.The mountain region data shown for Fig. 4, the present invention obtains 3D velocity field speed gradually changes to deep layer from earth's surface, spatially uniform to all directions spread, changes nature, without substantially Anomalous body occurs, and more uniform at adjacent ground surface also ratio, does not occur what conventional ray tomography acutely caused owing to earth's surface changes Result of calculation is uneven, VELOCITY DISTRIBUTION is abnormal.It addition, the present invention is when calculating Fig. 4 result, only with 1 line of on cluster 1 node Journey, time-consuming 3 minutes, and conventional ray tomography 8 nodal parallel in same cluster, every node uses 10 threads, and time-consuming 30 minutes Obtain similar results.Therefore the odds for effectiveness of the present invention is clearly.

Above-described detailed description of the invention, has been carried out the purpose of the present invention, technical scheme and beneficial effect further Describe in detail, be it should be understood that the detailed description of the invention that the foregoing is only the present invention, be not intended to limit the present invention Protection domain, all within the spirit and principles in the present invention, any modification, equivalent substitution and improvement etc. done, all should comprise Within protection scope of the present invention.

Claims (8)

1. a three-dimensional is without ray tracing diving Wave chromatography imaging method, it is characterised in that the method includes:

The single big gun first arrival of pickup, each single big gun first arrival to pickup is spaced selected multiple azimuthal first arrivals according to orientation angles, and Each azimuth first arrival is sorted according to offset distance incremental manner, forms the first arrival curve in the range of 0～x；Wherein, x is Large offseting distance；

With offset distance as abscissa, first arrival time as vertical coordinate, the first arrival curve in the range of 0～x is carried out lower order polynomial expressions Little square law overall fit, obtains the azimuth multinomial coefficient accordingly of each single big gun first arrival；

The azimuth slowness curve of the most each single big gun first arrival is obtained according to described multinomial coefficient；

Azimuth slowness curve according to described each single big gun first arrival obtains the azimuth that each single big gun first arrival of pickup is selected The speed of diving Wave inflection point and the degree of depth accordingly；

Speed and the degree of depth of the azimuth diving Wave inflection point accordingly that each single big gun first arrival according to pickup is selected are interpolated to 3D velocity field.

2. the method for claim 1, it is characterised in that the azimuth pair that each single big gun first arrival of described pickup is selected Should ground diving Wave inflection point velocity acquiring method be:

The azimuth slowness curve of each single big gun first arrival of pickup is appointed in the range of 0～x that to take M point be diving Wave inflection point；

Obtain the inverse of the slowness curve value of inflection point i correspondence position, obtain the speed of inflection point i；Wherein, i=1,2 ..., M.

3. method as claimed in claim 2, it is characterised in that the azimuth pair that each single big gun first arrival of described pickup is selected Should ground diving Wave inflection point degree of depth acquisition methods be:

Integral formula is used to obtain the degree of depth of inflection point i；Wherein, described integral formula is:

$z_i=\frac{1}{\mathrm{\π}}{\∫}_0^{x_i}{\cosh }^{-1}\left(\frac{\frac{dt}{dx}}{{\left(\frac{dt}{dx}\right)}_i}\right)dx$

Wherein, z_iFor the degree of depth that inflection point i is corresponding, x_iFor the offset distance that inflection point i is corresponding；T represents first arrival time, and d is for differentiating Operator.

4. the method for claim 1, it is characterised in that the azimuth slowness curve of described each single big gun first arrival obtains Method is:

Multinomial is obtained according to described multinomial coefficient；

Described multinomial is carried out derivation, it is thus achieved that the azimuth slowness curve of each single big gun first arrival.

5. a three-dimensional is without ray tracing diving Wave laminated imaging device, it is characterised in that this device includes:

First arrival curve acquisition unit, is used for picking up single big gun first arrival, and each single big gun first arrival to pickup is selected according to orientation angles interval Determine the azimuthal first arrival of at least two, and each azimuth first arrival is sorted according to offset distance incremental manner, form 0～x model Enclose interior first arrival curve；Wherein, x is maximum offset；

Fitting unit, for offset distance as abscissa, first arrival time as vertical coordinate, the first arrival curve in the range of 0～x is carried out Lower order polynomial expressions method of least square overall fit, obtains the azimuth multinomial coefficient accordingly of each single big gun first arrival；

Azimuth slowness curve acquiring unit, for obtaining the orientation of the most each single big gun first arrival according to described multinomial coefficient Angle slowness curve；

The speed of diving Wave inflection point and degree of depth acquiring unit, for the azimuth slowness curve according to described each single big gun first arrival Obtain speed and the degree of depth of the azimuth diving Wave inflection point accordingly that each single big gun first arrival picked up is selected；

Interpolating unit, the speed of the azimuth diving Wave inflection point accordingly for being selected according to each single big gun first arrival of pickup It is interpolated to 3D velocity field with the degree of depth.

6. device as claimed in claim 5, it is characterised in that the speed of described diving Wave inflection point and degree of depth acquiring unit bag Include: diving Wave inflection point acquisition module and the first computing module；Wherein,

Described diving Wave inflection point acquisition module, is used for the azimuth slowness curve to each single big gun first arrival picked up at 0～x model Enclose interior taking M point is diving Wave inflection point；

Described first computing module, for obtaining the inverse of the slowness curve value of inflection point i correspondence position, obtains inflection point i's Speed；Wherein, i=1,2 ..., M.

7. device as claimed in claim 6, it is characterised in that the speed of described diving Wave inflection point and degree of depth acquiring unit are also Including the second computing module；Wherein,

Described second computing module, for using integral formula to obtain the degree of depth of inflection point i；Wherein, described integral formula is:

$z_i=\frac{1}{\mathrm{\π}}{\∫}_0^{x_i}{\cosh }^{-1}\left(\frac{\frac{dt}{dx}}{{\left(\frac{dt}{dx}\right)}_i}\right)dx$

Wherein, z_iFor the degree of depth that inflection point i is corresponding, x_iFor the offset distance that inflection point i is corresponding, t represents first arrival time.

8. device as claimed in claim 5, it is characterised in that described azimuth slowness curve acquiring unit includes: multinomial Acquisition module and derivation module；Wherein,

Described multinomial acquisition module, for obtaining multinomial according to described multinomial coefficient；

Described derivation module, for carrying out derivation to described multinomial, it is thus achieved that the azimuth slowness curve of each single big gun first arrival.