CN102590858A - Two-way wave imaging method based on broadband wavelet reconstruction - Google Patents

Abstract

The invention discloses a two-way wave imaging method based on broadband wavelet reconstruction. The method comprises the following steps of: (1) carrying out frequency spectrum analysis on a single shot in seismic acquisition and determining the main frequency and dominant frequency distribution range of the single shot; (2) determining a wave form and an amplitude spectrum of a Ricker wavelet according to the main frequency of seismic data; (3) constructing a broadband source wavelet in combination with the frequency-band range of seismic data; (4) realizing forward modeling of the source wavelet and recording reverse-time extrapolation in a seismic wave field; (5) segmenting the recording time in the forward pass of a shot wave field and storing only two levels of wave field data at the beginning in each segment; and (6) carrying out reverse-time extrapolation and relatively imaging seismic wave fields. According to the method, the best matching of the source wavelet and the seismic recording and the precise extrapolation of the full waves are realized, the difficulty of precise imaging of complex construction and complex seismic wave fields is solved well, the amplitude and phase information of deep seismic imaging is protected effectively and the reliability of precisely imaging earthquake in a deep domain is guaranteed.

Description

Round trip wave imaging method based on the reconstruct of wideband wavelet

Technical field

The invention belongs to the oil seismic exploration technical field, relate in particular to a kind of new round trip wave imaging method that is applicable to polytype complicated seismic wave field, complex structure accurately image based on the reconstruct of wideband wavelet.

Background technology

In recent years, along with deepening continuously of oil seismic exploration work, seismic prospecting develops to complex structural area, and the problem that seismic survey work faces is complicated more, seeks out the accurate structural feature of underground medium difficulty more.Imaging technique has developed for many years, also is the effective means of obtaining underground structure.In prestack depth domain imaging method; At present the method that adopts of industry member comprises that these two class methods are difficult to handle the violent high steep dip structure imaging problem of seismic event lateral speed change based on the Integral Solution of Wave Equation method of ray theory with based on the differential wave equation one way ripple solution of wave theory.

Recently; The geophysical survey field higher reverse-time migration formation method of a kind of precision that grows up; This method adopts the round trip ripple to find the solution the differential wave equation; Advantages such as influence, the imaging precision that not constructed by medium lateral speed change and high steep dip is high, the correct imaging of bow-tie capable of using have remedied the image defects that conventional seismic migration faced theoretically.But in the process of using, because the influence of difference, difference scheme inverse time wave field extrapolation algorithm and the image-forming condition of source wavelet and seismologic record, imaging results is undesirable aspect the accuracy of frequency, image space.Imaging has certain influence to source wavelet to prestack round trip ripple, its influence imaging phase place and imaging resolution. choose single-frequency Ricker wavelet usually.Therefore, source wavelet and seismologic record wavelet there are differences, and seismic imaging resolution is lower, influences the seismic imaging effect.

Summary of the invention

Technical matters to be solved by this invention is to have overcome conventional round trip ripple imaging technique to cause the seismic imaging frequency band narrow because of single wavelet frequency the false defective of frequency content; Warp is research and repetition test repeatedly, and a kind of wideband source wavelet of reconstruct, based on the reverse-time migration high precision formation method of multiple dimensioned wideband source wavelet; This method can make source wavelet more near the seismologic record wavelet, the land geological data accurately image that realization theory model data, marine seismic data and wavelet thereof are changeable; It is accurate to have the seismic imaging phase place, the characteristics that resolution is higher and image space is true and reliable.The technical scheme that technical solution problem of the present invention is taked is: a kind of round trip wave imaging method based on the reconstruct of wideband wavelet is characterized in that: reconstruct of wideband source wavelet and inverse time wave field extrapolation, and concrete steps comprise:

A, single big gun of earthquake-capturing is done spectrum analysis, confirm the dominant frequency of single big gun, visual dominant frequency scope is between 20～40Hz, and the dominant frequency distribution range can be between 5～70Hz;

B, utilize formula to confirm the waveform and the spectral amplitude of Ricker wavelet frequently according to the earthquake data owner;

r(t)＝[1-2(πwt) ²]exp[1-(πwt) ²] (1)

$R\left(f\right)=\frac{2f^2}{g^3\sqrt{\mathrm{\π}}}\exp [-{\left(\frac{f}{w}\right)}^2]---\left(2\right)$

(1) expression Ricker wavelet waveform in the formula, (2) expression Ricker wavelet spectral amplitude;

C, on step B basis, utilize formula (3)～(6), make up the wideband source wavelet in conjunction with the geological data frequency band range;

$w\left(t\right)=\frac{1}{w_2-w_1}{\∫}_{w_1}^{w_2}r\left(t\right)\mathrm{dw}---\left(3\right)$

$w\left(t\right)=\frac{1}{w_2-w_1}{\∫}_{w_1}^{w_2}[1-2{\left(\mathrm{\πwt}\right)}^2]\exp [-{\left(\mathrm{\πwt}\right)}^2]\mathrm{dw}---\left(4\right)$

$w\left(t\right)=\frac{1}{w_2-w_1}\left\{w_2\exp \right[-{\left(\mathrm{\π}{w}_{2}t\right)}^2]-w_1\exp [-{\left(\mathrm{\π}{w}_{1}t\right)}^2\left]\right\}---\left(5\right)$

$Y\left(f\right)=\frac{1}{(w_2-w_1)\sqrt{\mathrm{\π}}}\left\{\exp \right[{-\left(\frac{f}{w_2}\right)}^2]-\exp [-{\left(\frac{f}{w_1}\right)}^2\left]\right\}---\left(6\right)$

W in the formula ₁, w ₂For the minimum maximum frequency of seismic data, confirm that according to results of spectral parameter area is generally 4～80Hz usually;

D, utilize time second order centered finite difference approximate according to three-dimensional medium round trip ACOUSTIC WAVE EQUATION

Utilize space high-order centered finite difference--approximate

The release truncation error is o (Δ x ^M, Δ y ^M, Δ z ^M, Δ t ²) three-dimensional higher difference wave field extrapolation equation:

$u_{i,j,k}^{n\±1}=2u_{i,j,k}^n-u_{i,j,k}^{n\stackrel{\→}{+}1}+\frac{1}{2}{\left(\frac{\mathrm{v\Δt}}{\mathrm{\Δx}}\right)}^2[{\mathrm{\ω}}_0{u}_{i,j,k}^n+\underset{m=1}{\overset{\frac{M}{2}}{\mathrm{\Σ}}}{\mathrm{\ω}}_m(u_{i+m,j,k}^n+u_{i-m,j,k}^n)]$

$+\frac{1}{2}{\left(\frac{\mathrm{v\Δt}}{\mathrm{\Δy}}\right)}^2[{\mathrm{\ω}}_0{u}_{i,j,k}^n+\underset{m=1}{\overset{\frac{M}{2}}{\mathrm{\Σ}}}{\mathrm{\ω}}_m(u_{i,j+m,k}^n+u_{i,j-m,k}^n)]---\left(7\right)$

$+\frac{1}{2}{\left(\frac{\mathrm{v\Δt}}{\mathrm{\Δz}}\right)}^2[{\mathrm{\ω}}_0{u}_{i,j,k}^n+\underset{m=1}{\overset{\frac{M}{2}}{\mathrm{\Σ}}}{\mathrm{\ω}}_m(u_{i,j,k+m}^n+u_{i,j,k-m}^n)]$

Adopt the following formula equation, can realize that source wavelet just drilling and writing down the extrapolation of seismic wave field inverse time;

E, according to step D, just pushing away in the process whole T segmentation writing time at the big gun wave field, add absorbing boundary condition simultaneously, only store the two-layer wave field data of this section when initial on each section and in machine, store;

F, after step e is accomplished, the extrapolation imaging of beginning inverse time; Two-layer wave field when this section that in this process, utilizes step e to store is initial recalculates whole wave field value of this section; And be kept in the machine internal memory; Time step of the record every backstepping of wave field in this section; Just with internal memory in the corresponding big gun wave field constantly preserved carry out relevant, through formula (8) to obtain the imaging results in this moment;

$\mathrm{Image}(x,z)={\∫}_0^{T\max }{P}_D(x,z,t)P_H(x,z,t)\mathrm{dt}---\left(8\right)$

Integrand P wherein _D(x, z, t) P _H(t) expression t constantly does Polaroid computing to whole wave field for x, z, and integration explanation image space Image (x, in z) similarly is the stack of a time step imaging; So the simple crosscorrelation image-forming condition has made full use of image-forming information, in the Enhanced Imaging signal, also effectively suppressed the imaging noise; According to above step, the wave field inverse time extrapolation that calculated amount is maximum realizes through GPU; And utilize the random velocity border to improve the wave field extrapolation concurrency of algorithm, solved the I/O problem of extensive storage.

Said structure wideband source wavelet adopts difference method realization source wavefield just drilling and is specially: on the corresponding single shot record of geological data; Carry out spectrum analysis and confirm frequency range; Make up source wavelet according to the earthquake recording frequency; Utilize high-order limited difference method just drilling source wavefield to the maximum record time, the wave field data are just being drilled in storage simultaneously.

Remarkable result of the present invention is:

(1), the inventive method realized the optimum matching of source wavelet and seismologic record, realized that the all-wave field accurately extrapolates; Solve the accurately image difficult problem of complicated seismic wave field well, effectively protected the amplitude and the phase information of deep earthquake imaging, guaranteed the reliability of degree of depth accurately image.

(2), the present invention makes up source wavelet by the frequency parameter of seismologic record, guaranteed the optimum matching of source wavelet and seismologic record.

(3), the simple crosscorrelation image-forming principle that adopts of the present invention, the simple crosscorrelation image-forming condition has made full use of image-forming information, in the Enhanced Imaging signal, has also effectively suppressed the imaging noise.

(4), the present invention adopts the wideband wavelet can effectively preserve the frequency band in the geological data, because the spectral amplitude of wideband wavelet skew more helps the analysis to migration result than Ricker wavelet amplitude of deflection spectrum bandwidth.

Description of drawings

Fig. 1 is a wideband wavelet reconstruct round trip ripple image-forming principle block diagram of the present invention

Fig. 2 a is a BLH seismologic record source map of the present invention

Fig. 2 b is a BLH seismologic record data spectrogram of the present invention

Fig. 3 a is a Ricker wavelet oscillogram of the present invention

Fig. 3 b is a Ricker wavelet spectrogram of the present invention

Fig. 4 a is a reconstruct wideband wavelet oscillogram of the present invention

Fig. 4 b is reconstruct wideband wavelet spectrum figure of the present invention

Fig. 5 a is 40Hz Ricker wavelet migration result figure of the present invention (pressure is made an uproar preceding)

Fig. 5 b is 40Hz Ricker wavelet migration result figure of the present invention (pressure is made an uproar back)

Fig. 6 a is wideband wavelet migration result figure of the present invention (pressure is made an uproar preceding)

Fig. 6 b is wideband wavelet migration result figure of the present invention (pressure is made an uproar back)

Fig. 7 a is a Ricker wavelet migrated section amplitude spectrogram of the present invention

Fig. 7 b is a wideband wavelet migrated section amplitude spectrogram of the present invention

Fig. 8 a is that the present invention extracts Ricker wavelet imaging results oscillogram

Fig. 8 b is a reconstruct wideband wavelet imaging results oscillogram of the present invention

Fig. 9 is one way ripple imaging results figure of the present invention

Figure 10 is wideband wavelet round trip ripple imaging results figure of the present invention

Embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is described in further detail

Embodiment 1

As shown in Figure 1, the embodiment of the invention provides wideband wavelet reconstruct round trip ripple imaging flow process:

At first determine the frequency trend scope according to e; Protection wave field, amplitude and frequency information when need handle to e; The parameter of confirming according to e is confirmed to make up the waveform and the spectral amplitude of Ricker wavelet the wideband source wavelet and obtain a according to the geological data dominant frequency, and e can obtain h according to step D, E.Can accomplish by step D, E by a → d, and preserve wave field value.In the process of practical application, because whole wave field information is not preserved in the restriction of machine internal memory and storage.By a to the d source wavefield along in the time forward extrapolation process, only store this section when initial two-layer wave field and add absorbing boundary condition.In extrapolating imaging process by e to the h inverse time, the two-layer wave field when utilizing this section of storing initial recalculates whole wave field value of this section, and is kept in the internal memory, also can be stored on the hard disk, reads out when forming images at the i place.The record every backstepping of wave field time step, just with internal memory in the big gun wave field in corresponding moment of preserving carry out relevantly, obtain the imaging results in this moment, finish the imaging processing repetition said process of other sections up to every section imaging.

Its principle of method of the present invention is: be the basis with seismologic record and Ricker wavelet; Carry out seismologic record analysis and wavelet reconstruct earlier; Structure carries out wave field with the more approaching wideband source wavelet of real seismic record just drills; Adopt advanced wave field extrapolation operator to carry out the inverse time extrapolation of seismologic record wave field simultaneously, through wave field related realization Depth Domain seismic imaging.

Embodiment 2

Be application example, the face of land, basin, the Caspian Sea, shore is main with the hills, grassland, and river, swampland, clay ground are arranged simultaneously, and middle low, two ends are high, and the northern cliff of displacement in work area is more, ravines and guillies criss-cross, and relief is bigger; Work area surface structure major part is three layers (weathering zone, reduction of speed band, high-velocity beds), and the variation of weathering zone speed and thickness is milder, and its speed is the 350-900 meter per second, and its one-tenth-value thickness 1/10 is a 10-15 rice, and relevant with face of land elevation; Adopt three-dimensional data (gathering in 2005,2006,2007,2008) in flakes; All be the 3-D seismics record that vibroseis is gathered, see from Fig. 7 a, seismic data is shallow, in, deep reflex ripple group is more complete; Energy is moderate; Signal to noise ratio (S/N ratio) is higher, and to overlap reflection wave groups clear continuously more, explains that the quality of source book is pretty good.But huge thick salt dome is grown by this area; Seismic wave field is very complicated; Exist differences such as seismic wave waveform, amplitude between the different masses three-dimensional; Because the complicacy of the face of land and underground structure causes this area's seismic imaging problem serious,, find that the conventional earthquake imaging technique of employing can't solve this district's accurately image problem through repetition test repeatedly.

We utilize the round trip wave imaging method that the present invention is based on the reconstruct of wideband wavelet to carry out the seismic imaging processing in the BLH basin, have obtained very desirable earthquake effect; Operation steps is following:

1) be that high-quality big gun collection is prepared in the skew of round trip ripple, the earthquake big gun of field acquisition record is carried out conventional processing;

2), at the enterprising line frequency analysis of spectrum of single big gun seismologic record, confirm frequency range (shown in Fig. 2 a, Fig. 2 b), from frequency analysis, 500-1200ms shallow-layer significant wave frequency mainly concentrates between the 8-75Hz, looks dominant frequency about 40Hz; 1600-2400ms objective interval significant wave frequency mainly concentrates between the 6-70Hz, looks dominant frequency about 30Hz; 3600-4400ms deep layer significant wave frequency mainly concentrates between the 5-50Hz, looks dominant frequency about 20Hz.

3) utilize frequency parameter to make up the wideband source wavelet

Referring to Fig. 3 a is the Ricker wavelet oscillogram, and Fig. 3 b is the Ricker wavelet spectrogram; Fig. 4 a is a reconstruct wideband wavelet oscillogram, and Fig. 4 b is reconstruct wideband wavelet spectrum figure; Frequency parameter by seismologic record makes up source wavelet, guarantees the optimum matching of source wavelet and seismologic record.

4), can realize that according to step D, E source wavelet just drills, the forward that forms focal point is the push wave field, and according to above-mentioned implementation storage wave field.

5), seismologic record is read in internal memory, according to given imaging space parameter, carry out the inverse time continuation of all-wave wave equation according to step D, E, extension equation is following:

$u_{i,j,k}^{n\±1}=2u_{i,j,k}^n-u_{i,j,k}^{n\stackrel{\‾}{+}1}+\frac{1}{2}{\left(\frac{\mathrm{v\Δt}}{\mathrm{\Δx}}\right)}^2[{\mathrm{\β}}_0{u}_{i,j,k}^n+\underset{m=1}{\overset{\frac{M}{2}}{\mathrm{\Σ}}}{\mathrm{\β}}_m(u_{i+m,j,k}^n+u_{i-m,j,k}^n)]$

$+\frac{1}{2}{\left(\frac{\mathrm{v\Δt}}{\mathrm{\Δy}}\right)}^2[{\mathrm{\ω\β}}_0{u}_{i,j,k}^n+\underset{m=1}{\overset{\frac{M}{2}}{\mathrm{\Σ}}}{\mathrm{\β}}_m(u_{i,j+m,k}^n+u_{i,j-m,k}^n)]$

$+\frac{1}{2}{\left(\frac{\mathrm{v\Δt}}{\mathrm{\Δz}}\right)}^2[{\mathrm{\ω}}_0{u}_{i,j,k}^n+\underset{m=1}{\overset{\frac{M}{2}}{\mathrm{\Σ}}}{\mathrm{\ω}}_m(u_{i,j,k+m}^n+u_{i,j,k-m}^n)]$

Calculating parameter:

When M=4, β ₀=-5.0, β ₁=2.666667, β ₂=-0.1666667

When M=6, β ₀=-5.444444, β ₁=3.000000,

β ₂＝-0.3000003，β ₃＝0.0222225，

When M=8, β ₀=-2.847222054, β ₁=3.20000000, β ₂=-0.4000002,

β ₃＝0.05079369，β ₄＝-0.003571436

When M=10, β ₀=-5.8544445, β ₁=3.333333, β ₂=-0.4761901,

β ₃＝0.07936513，β ₄＝-0.009920621，β ₅＝0.0006349185

6), adopt the dependent imaging condition to carry out the wave field dependent imaging;

Consider the realizability of complicated wave field, the simple crosscorrelation image-forming principle that we adopt, the imaging formula of simple crosscorrelation image-forming condition is (8) formula, the simple crosscorrelation image-forming condition has made full use of image-forming information, in the Enhanced Imaging signal, has also effectively suppressed the imaging noise.

7), according to the round trip wave imaging method that the present invention is based on the reconstruct of wideband wavelet, theoretical model is carried out numerical experimentation;

Referring to Fig. 5 a is 40Hz Ricker wavelet migration result figure (pressure is made an uproar preceding), and Fig. 5 b is 40Hz Ricker wavelet migration result figure (pressure is made an uproar back); Fig. 6 a is wideband wavelet migration result figure (pressure is made an uproar preceding), and Fig. 6 b is wideband wavelet migration result figure (pressure is made an uproar back).No matter two kinds of wavelets are to contrast after preceding contrast of denoising or the denoising; Visually all can not find out tangible difference; In order further to analyze the influence of these two kinds of wavelets to migration result, we analyze the spectral amplitude that two kinds of wavelets produce section, shown in Fig. 7 a, Fig. 7 b.Simultaneously also analyzed the waveform character that two kinds of wavelets obtain imaging results, shown in Fig. 8 a, Fig. 8 b.Find out that by figure therefore the spectral amplitude of wideband wavelet skew, uses the broadband wavelet more can preserve the effective band in the geological data than Ricker wavelet amplitude of deflection spectrum bandwidth, helps the migration result analysis.

8), according to the present invention technology, the actual geological data of BIH is made an experiment

Referring to Fig. 9 is one way ripple imaging results, and Figure 10 is a wideband wavelet round trip ripple imaging results; From comparison diagram, can find out; The moving equation Depth Domain imaging technique of wideband wavelet round trip wave-wave has been realized the accurate playback to salt dome border and salt dome flank; Make interface, salt brae, salt flank border, greater than tectonic energy accurately image under 90 ° of special salt of salt flank, the imaging section predominant frequency is higher simultaneously, frequency information abundant, more helps seismic reservoir study; Through the test of theoretical model tentative calculation and real data, proved the advantage that the round trip wave imaging method based on the reconstruct of wideband wavelet has.

The above, as preferred embodiment of the present invention, in order to restriction the present invention, all within spirit of the present invention and principle, any modification of being done is not equal to replacement, improves and waits and all should be included within protection scope of the present invention.

Claims (2)

1. round trip wave imaging method based on the reconstruct of wideband wavelet is characterized in that: reconstruct of wideband source wavelet and inverse time wave field extrapolation, and concrete steps comprise:

A, single big gun of earthquake-capturing is done spectrum analysis, confirm the dominant frequency of single big gun, visual dominant frequency scope is between 20～40Hz, and the dominant frequency distribution range can be between 5～70Hz;

B, utilize formula to confirm the waveform and the spectral amplitude of Ricker wavelet frequently according to the earthquake data owner;

r(t)＝[1-2(πwt) ²]exp[1-(πwt) ²] (1)

$R\left(f\right)=\frac{2f^2}{g^3\sqrt{\mathrm{\π}}}\exp [-{\left(\frac{f}{w}\right)}^2]---\left(2\right)$

(1) expression Ricker wavelet waveform in the formula, (2) expression Ricker wavelet spectral amplitude;

C, on step B basis, utilize formula (3)～(6), make up the wideband source wavelet in conjunction with the geological data frequency band range;

$w\left(t\right)=\frac{1}{w_2-w_1}{\∫}_{w_1}^{w_2}r\left(t\right)\mathrm{dw}---\left(3\right)$

$w\left(t\right)=\frac{1}{w_2-w_1}{\∫}_{w_1}^{w_2}[1-2{\left(\mathrm{\πwt}\right)}^2]\exp [-{\left(\mathrm{\πwt}\right)}^2]\mathrm{dw}---\left(4\right)$

$w\left(t\right)=\frac{1}{w_2-w_1}\left\{w_2\exp \right[-{\left(\mathrm{\π}{w}_{2}t\right)}^2]-w_1\exp [-{\left(\mathrm{\π}{w}_{1}t\right)}^2\left]\right\}---\left(5\right)$

$Y\left(f\right)=\frac{1}{(w_2-w_1)\sqrt{\mathrm{\π}}}\left\{\exp \right[{-\left(\frac{f}{w_2}\right)}^2]-\exp [-{\left(\frac{f}{w_1}\right)}^2\left]\right\}---\left(6\right)$

W in the formula ₁, w ₂For the minimum maximum frequency of seismic data, confirm that according to results of spectral parameter area is generally 4～80H usually _z

D, utilize time second order centered finite difference approximate according to three-dimensional medium round trip ACOUSTIC WAVE EQUATION

Utilize space high-order centered finite difference approximate

The release truncation error is o (Δ x ^M, Δ y ^M, Δ z ^M, Δ t ²) three-dimensional higher difference wave field extrapolation equation:

$u_{i,j,k}^{n\±1}=2u_{i,j,k}^n-u_{i,j,k}^{n\stackrel{\‾}{+}1}+\frac{1}{2}{\left(\frac{\mathrm{v\Δt}}{\mathrm{\Δx}}\right)}^2[{\mathrm{\ω}}_0{u}_{i,j,k}^n+\underset{m=1}{\overset{\frac{M}{2}}{\mathrm{\Σ}}}{\mathrm{\ω}}_m(u_{i+m,j,k}^n+u_{i-m,j,k}^n)]$

$+\frac{1}{2}{\left(\frac{\mathrm{v\Δt}}{\mathrm{\Δy}}\right)}^2[{\mathrm{\ω}}_0{u}_{i,j,k}^n+\underset{m=1}{\overset{\frac{M}{2}}{\mathrm{\Σ}}}{\mathrm{\ω}}_m(u_{i,j+m,k}^n+u_{i,j-m,k}^n)]---\left(7\right)$

$+\frac{1}{2}{\left(\frac{\mathrm{v\Δt}}{\mathrm{\Δz}}\right)}^2[{\mathrm{\ω}}_0{u}_{i,j,k}^n+\underset{m=1}{\overset{\frac{M}{2}}{\mathrm{\Σ}}}{\mathrm{\ω}}_m(u_{i,j,k+m}^n+u_{i,j,k-m}^n)]$

Adopt the following formula equation, can realize that source wavelet just drilling and writing down the extrapolation of seismic wave field inverse time;

E, according to step D, just pushing away in the process whole T segmentation writing time at the big gun wave field, add absorbing boundary condition simultaneously, only store the two-layer wave field data of this section when initial on each section and in machine, store;

F, after step e is accomplished, the extrapolation imaging of beginning inverse time; Two-layer wave field when this section that in this process, utilizes step e to store is initial recalculates whole wave field value of this section; And be kept in the machine internal memory; Time step of the record every backstepping of wave field in this section; Just with internal memory in the corresponding big gun wave field constantly preserved carry out relevant, through formula (8) to obtain the imaging results in this moment;

$\mathrm{Image}(x,z)={\∫}_0^{T\max }{P}_D(x,z,t)P_H(x,z,t)\mathrm{dt}---\left(8\right)$

Integrand P wherein _D(x, z, t) P _H(t) expression t constantly does Polaroid computing to whole wave field for x, z, and (x, in z) similarly is the stack of a time step imaging to integration explanation image space Image.

2. the round trip wave imaging method based on the reconstruct of wideband wavelet according to claim 1; It is characterized in that; Said structure wideband source wavelet adopts difference method realization source wavefield just drilling and is specially: on the corresponding single shot record of geological data, carry out spectrum analysis and confirm frequency range, make up source wavelet according to the earthquake recording frequency; Utilize high-order limited difference method just drilling source wavefield to the maximum record time, the wave field data are just being drilled in storage simultaneously.

Images