CN103091710B - Reverse time migration imaging method and device - Google Patents

Abstract

The invention relates to a reverse time migration imaging method and a device, wherein the method comprises the following steps: acquiring seismic source wave field information and wave field information of a wave detection point; according to the acquired seismic source wave field information and the acquired wave field information of the wave detection point, the seismic source wave field is separated into a seismic source uplink wave field and a seismic source downlink wave field, and the wave detection point wave field is separated into a wave detection point uplink wave field and a wave detection point downlink wave field; and carrying out reverse time migration imaging processing on the separated seismic source wave field and the separated wave field of the wave detection point to obtain a reverse time migration imaging section. The reverse time migration imaging method and the reverse time migration imaging device eliminate low-frequency noise generated in the reverse time migration process, have high amplitude preservation, keep good parallel characteristics of internal wave field calculation, are very suitable for being carried out on a Graphics Processing Unit (GPU)/Central Processing Unit (CPU) heterogeneous platform, and greatly improve the calculation efficiency of reverse time migration.

Description

A kind of reverse-time migration formation method and device

Technical field

The invention relates to geophysical survey seismic data processing technology field, especially about oil and gas exploration seismic data processing technology field, specifically about a kind of reverse-time migration formation method and device.

Background technology

Along with the development of oil-gas exploration technology, architectonic " two complexity " region under the target of oil-gas exploration turns to complex near surface conditions and intricately gradually, and traditional formation method cannot meet the imaging in " two complexity " region.The depth migration imaging method of current domestic heavy industrialization application is mainly based on Kirchhoff integral method and the beam class offset method of ray theory, but these class methods are approximate solutions of wave equation, they can not imaging very well for high steep dip, and complex structure is usually along with strong lateral speed change, therefore result has multipath, thus can limit the counting yield based on ray theory offset method.For solving the problems of the technologies described above, prior art provides a kind of wave equation migration algorithm based on one-way wave, the paraxial approximation of wave equation theory is utilized to realize the extrapolation of wave field, can well imaging under specific angle, but when stratum is close to time even more than 90 degree, this method can lose efficacy equally.

For solving the problems of the technologies described above, prior art proposes a kind of reverse-time migration method, reverse-time migration method is just proposed in nineteen eighty-two SEG meeting by people such as Whitemore N D. the earliest, but be limited by its huge calculated amount and fancy price, this method never has large-scale application in actual production, and in recent years, along with super computer group and GPU (Graphic Processing Unit, graphic process unit) development of technology, reverse-time migration technology is gradually by large-scale application.Pre-Stack Reverse method can be divided into three steps substantially: the forward extrapolation 1, carrying out shot point wave field in time domain; 2, geophone station wave field back-extrapolate is carried out in time domain; 3, the position utilizing effective image-forming condition to occur in reflection horizon is built into picture.At present, the reverse-time migration wave field extrapolation of heavy industrialization, is remained and to be realized by following Chang Midu ACOUSTIC WAVE EQUATION (1):

$\frac{1}{V^2(x,y,z)}\frac{{\∂}^{2}P}{\∂t^2}=\frac{{\∂}^{2}P}{\∂x^2}+\frac{{\∂}^{2}P}{\∂y^2}+\frac{{\∂}^{2}P}{\∂z^2}---\left(1\right)$

Wherein t represents time coordinate, and x, y, z represent volume coordinate, and P represents the pressure field of wave field at locus (x, y, z) place, and V represents the medium velocity function of vertical transverse variable.In reverse-time migration imaging process, shot point wave field and geophone station wave field all realize extrapolation by equation (1), and be embodied as time usually utilize shot point and geophone station extrapolation wave field zero-lag cross-correlation to build image-forming condition, following equation (2):

$I(x,y,z)=\underset{0}{\overset{T_{\max }}{\∫}}s(t,x,y,z)r(t,x,y,z)\mathrm{dt}---\left(2\right)$

In equation (2), s is the source wavefield of forward extrapolation, and r is the geophone station wave field of back-extrapolate, and I is imaging results, T _maxfor the maximum time of wave field extrapolation; Utilize this image-forming condition to carry out reverse-time migration to need to realize three links, first, source wavefield is carried out forward continuation, preserve the wave field information of each time step; Then, geophone station wave field is carried out backward extension, preserve the wave field information of each time step; Finally, the source wavefield and the geophone station wave field that read synchronization respectively carry out imaging computing, add up into imaging space, just can obtain final imaging results.

But, the image-forming condition that equation (2) defines can produce the low frequency noise of a large amount of strong amplitude usually, skew illusion is there is sometimes at some reflecting interface places, particularly above strong reflection interface, these low frequency noises even can pollute useful signal and the tectonic structure of shallow-layer thoroughly be flooded; In actual application, for effectively eliminating these low frequency noises, generally can adopt following three kinds of main denoising thinkings, that is: denoising in wave field communication process, denoising or the denoising of imaging post filtering method when applying image-forming condition.But any one in three kinds of denoising schemes all more or less can hurt useful signal, thus guarantor's width of the data of destruction; By analysis and research, finding to produce the main cause of these low frequency noises is that the cross-correlation of source wavefield and geophone station wave field not only can produce amplitude at reflecting interface place, simultaneously at the non-reflective some place in the whole path of wave traveling, also amplitude can be produced, if by these amplitudes along temporal summation, the low frequency noise of strong amplitude will be produced.In order to eliminate this low frequency noise, various denoising method must be adopted, no matter but which kind of denoising method, all can destroy the useful signal of data, and destroy guarantor's width of reverse-time migration.

Summary of the invention

For overcoming problems of the prior art, the invention provides a kind of reverse-time migration formation method and device, in actual application, can't low frequency noise be produced, there is very high guarantor's width.

The invention provides a kind of reverse-time migration formation method, described method comprises: obtain source wavefield information and geophone station wave field information; According to the source wavefield information obtained and geophone station wave field information, source wavefield being separated into focus upstream wave field and focus down-going wave fields, is geophone station upstream wave field and geophone station down-going wave fields by geophone station wave field separation; Reverse-time migration imaging processing is carried out to the source wavefield after separation and geophone station wave field, obtains reverse-time migration imaging section;

Described acquisition source wavefield information and geophone station wave field information comprise:

Obtain single big gun data, and prestack preprocessing is carried out to single big gun data;

Inverse time extrapolation is spreaded to outside the venue to the forward wave of single big gun data that prestack preprocessing exports, obtains source wavefield information and the geophone station wave field information of each time step.

The present invention also provides a kind of reverse-time migration imaging device, and described device comprises: wave field information acquisition unit, for obtaining source wavefield information and geophone station wave field information; Wave field separation unit, for according to obtain source wavefield information and geophone station wave field information, source wavefield being separated into focus upstream wave field and focus down-going wave fields, is geophone station upstream wave field and geophone station down-going wave fields by geophone station wave field separation; Image-generating unit, for carrying out reverse-time migration imaging processing to the source wavefield after separation and geophone station wave field, obtains reverse-time migration imaging section;

Described wave field information acquisition unit comprises:

Pretreatment module, for obtaining single big gun data, and carries out prestack preprocessing to single big gun data;

Extrapolation process module, the forward wave for the single big gun data exported prestack preprocessing spreads to inverse time extrapolation outside the venue, obtains source wavefield information and the geophone station wave field information of each time step.

The reverse-time migration formation method that the embodiment of the present invention provides and device, eliminate the low frequency noise produced in reverse-time migration process, there is very high guarantor's width, and maintain inner wave field and calculate the good Concurrent Feature had, be highly suitable for GPU/CPU (Central Processing Unit, central processing unit) heterogeneous platform carries out, improve the counting yield of reverse-time migration greatly.

Accompanying drawing explanation

Accompanying drawing described herein is used to provide a further understanding of the present invention, forms a application's part, does not form limitation of the invention.In the accompanying drawings:

Fig. 1 is the process flow diagram of a kind of reverse-time migration formation method that the embodiment of the present invention provides.

Fig. 2 is the horizontal layer model schematic of the different travel paths of the same source wavefield that the embodiment of the present invention provides.

Fig. 3 is the process flow diagram of a kind of reverse-time migration formation method that the embodiment of the present invention provides.

Fig. 4 is a kind of reverse-time migration imaging device module map that the embodiment of the present invention provides.

Embodiment

For making the object, technical solutions and advantages of the present invention clearly understand, below in conjunction with embodiment and accompanying drawing, the present invention is described in further details.At this, exemplary embodiment of the present invention and illustrating for explaining the present invention, but not as a limitation of the invention.

The embodiment of the present invention provides a kind of reverse-time migration formation method and device, and below in conjunction with accompanying drawing, the present invention is described in detail.

Embodiment one

Fig. 1 is the process flow diagram of a kind of reverse-time migration formation method that the embodiment of the present invention provides, and as shown in Figure 1, reverse-time migration formation method comprises the steps:

S101, obtains source wavefield information and geophone station wave field information.

In embodiments of the present invention, step S101 can comprise following sub-step:

Obtain single big gun data, and prestack preprocessing is carried out to single big gun data;

Inverse time extrapolation is spreaded to outside the venue to the forward wave of single big gun data that prestack preprocessing exports, obtains source wavefield information and the geophone station wave field information of each time step.

Concrete, single big gun data of earthquake-capturing can be loaded; The work of the prestack preprocessing such as static correction, denoising is carried out to the single big gun data of loading, to obtain high s/n ratio, high single big gun data of protecting width; The forward wave providing relatively accurate velocity field to realize earthquake list big gun data on GPU/CPU heterogeneous platform spreads to inverse time extrapolation outside the venue, obtains the source wavefield information of each time step and geophone station wave field information and stores.

S102, according to the source wavefield information obtained and geophone station wave field information, source wavefield being separated into focus upstream wave field and focus down-going wave fields, is geophone station upstream wave field and geophone station down-going wave fields by geophone station wave field separation.

Fig. 2 is the horizontal layer model schematic of the different travel paths of the same source wavefield that the embodiment of the present invention provides, and as shown in Figure 2, n represents normal orientation; I represents incident wave; T represents transmitted wave; R represents reflection wave, and along wave trajectory, shot point wave field and geophone station wave field have identical direction usually, and meanwhile, incident field and reflected wave field have contrary direction in the projection of the normal orientation of reflecting interface.According to the direction of propagation of source wavefield and geophone station wave field, two wave field separations are become its respective upstream wave field and down-going wave fields, carry out the later focus of wave field separation relevant in the projection of normal direction with its direction of propagation with the correlativity of geophone station wave field, when they have contrary projecting direction, after two wave field separations, have at least a meeting to be zero, only can produce imaging at reflection spot place, and would not imaging be produced at non-reflective some place.

In embodiments of the present invention, propose a kind of effective method source wavefield being become its uplink and downlink component with geophone station wave field separation, mainly uplink and downlink ripple is separated it in F-K territory.

A bit (x, y, z=z0) place on earth's surface, source wavefield s (t, x, y, z) and geophone station wave field r (t, x, y, z) can realize being separated of focus and geophone station wave field uplink and downlink ripple by Fourier transform.At Fourier, upstream wave field can be successfully separated with down-going wave fields, and can be expressed as following equation:

$S_u(\mathrm{\&omega;},k_z)=\left\{\begin{array}{cc}s(\mathrm{\&omega;},k_z)& \mathrm{\&omega;}{k}_z\&GreaterEqual;0\\ 0& \mathrm{\&omega;}{k}_z<0\end{array}\right.---\left(3\right)$

$S_d(\mathrm{\&omega;},k_z)=\left\{\begin{array}{cc}s(\mathrm{\&omega;},k_z)& \mathrm{\&omega;}{k}_z<0\\ 0& \mathrm{\&omega;}{k}_z\&GreaterEqual;0\end{array}\right.---\left(4\right)$

$R_u(\mathrm{\&omega;},k_z)=\left\{\begin{array}{cc}R(\mathrm{\&omega;},k_z)& \mathrm{\&omega;}{k}_z\&GreaterEqual;0\\ 0& \mathrm{\&omega;}{k}_z<0\end{array}\right.---\left(5\right)$

$R_d(\mathrm{\&omega;},k_z)=\left\{\begin{array}{cc}R(\mathrm{\&omega;},k_z)& \mathrm{\&omega;}{k}_z<0\\ 0& \mathrm{\&omega;}{k}_z\&GreaterEqual;0\end{array}\right.---\left(6\right)$

In formula, S _u, S _drepresent the Fourier transform of focus uplink and downlink wave field respectively, R _u, R _drepresent the Fourier transform of geophone station uplink and downlink wave field respectively.

S103, carries out reverse-time migration imaging processing to the source wavefield after separation and geophone station wave field, obtains reverse-time migration imaging section.

In embodiments of the present invention, by be separated after source wavefield and geophone station wave-field conversion to time domain, just can obtain the time domain image-forming condition of the reverse-time migration based on wave field separation, the expression formula being converted to time domain is respectively:

$s_u(t,x,y,z)=\underset{-\&infin;}{\overset{+\&infin;}{\&Integral;}}\underset{-\&infin;}{\overset{+\&infin;}{\&Integral;}}{S}_u(\mathrm{\&omega;},k_z)e^{i(\mathrm{tw}+z{k}_z)}\mathrm{d\&omega;d}{k}_z---\left(7\right)$

$s_d(t,x,y,z)=\underset{-\&infin;}{\overset{+\&infin;}{\&Integral;}}\underset{-\&infin;}{\overset{+\&infin;}{\&Integral;}}{S}_d(\mathrm{\&omega;},k_z)e^{i(\mathrm{tw}+z{k}_z)}\mathrm{d\&omega;d}{k}_z---\left(8\right)$

$r_u(t,x,y,z)=\underset{-\&infin;}{\overset{+\&infin;}{\&Integral;}}\underset{-\&infin;}{\overset{+\&infin;}{\&Integral;}}{R}_u(\mathrm{\&omega;},k_z)e^{i(\mathrm{tw}+z{k}_z)}\mathrm{d\&omega;d}{k}_z---\left(9\right)$

$r_d(t,x,y,z)=\underset{-\&infin;}{\overset{+\&infin;}{\&Integral;}}\underset{-\&infin;}{\overset{+\&infin;}{\&Integral;}}{R}_d(\mathrm{\&omega;},k_z)e^{i(\mathrm{tw}+z{k}_z)}\mathrm{d\&omega;d}{k}_z---\left(10\right)$

In reverse-time migration, focus and geophone station wave field extrapolation utilize omnidistance Acoustic Wave-equation to launch, and it comprises source wavefield and geophone station wave field two ingredients, can be expressed as following expression:

s(t,x,y,z)＝s _d(t,x,y,z)+s _u(t,x,y,z) (11)

r(t,x,y,z)＝r _d(t,x,y,z)+r _u(t,x,y,z) (12)

In formula, behalf source wavefield, s ^drepresent the down-going wave fields of focus, s _urepresent the upstream wave field of focus, r represents geophone station wave field, r ^drepresent geophone station down-going wave fields, r _urepresent geophone station upstream wave field.Carry it into equation (2) respectively and just can obtain four cross correlation results:

$\begin{array}{c}I(x,y,z)=\underset{0}{\overset{T\max }{\&Integral;}}{s}_d(t,x,y,z)r_u(t,x,y,z)\mathrm{dt}+\underset{0}{\overset{T\max }{\&Integral;}}{s}_u(t,x,y,z)r_d(t,x,y,z)\mathrm{dt}\\ +\underset{0}{\overset{T\max }{\&Integral;}}{s}_d(t,x,y,z)r_d(t,x,y,z)\mathrm{dt}+\underset{0}{\overset{T\max }{\&Integral;}}{s}_u(t,x,y,z)r_u(t,x,y,z)\mathrm{dt}\\ =I_{z1}(x,y,z)+I_{z2}(x,y,z)+I_{z3}(x,y,z)+I_{z4}(x,y,z)\end{array}---\left(13\right)$

In equation (13), I _z1represent that the cross-correlation of focus down-going wave fields and geophone station upstream wave field (is expressed as I _z1), its essence is the wave equation migration of one-way wave; I _z2represent the cross-correlation of focus upstream wave field and geophone station down-going wave fields; I _z3represent the cross-correlation of focus down-going wave fields and geophone station down-going wave fields; I _z4represent the cross-correlation of focus upstream wave field and geophone station upstream wave field.According to ray theory, some reflection spot place, incident wave is down going wave, and reflection wave is upward traveling wave; And some reflection spot place, incident wave is upward traveling wave, and reflection wave is down going wave, therefore two reflections is all participated in into, and ray tracing can be utilized to carry out imaging, that is, only needs I _z1and I _z2two, just can realize reverse-time migration imaging.The result that remaining two parts produce is low frequency noise, and no matter two wave fields that is utilizing the direction of propagation identical are down going wave I _z3or upward traveling wave I _z4, they are carried out cross-correlation along whole raypath, and its cross correlation results is the low frequency noise of imaging space.Now, the cross-correlation image-forming condition that effectively can be eliminated low frequency noise can be obtained:

I(x,y,z)＝I _z1(x,y,z)+I _z2(x,y,z) (14)

The image-forming condition of equation (14), is finally expressed as under time domain:

$I(x,y,z)=\underset{0}{\overset{T_{\max }}{\&Integral;}}[s_d(t,x,y,z)r_u(t,x,y,z)+r_d(t,x,y,z)s_u(t,x,y,z)]\mathrm{dt}---\left(15\right)$

According to equation (15), reverse-time migration imaging is carried out to the focus after separation and geophone station wave field, export final reverse-time migration imaging section.

The reverse-time migration formation method that the embodiment of the present invention provides, along wave trajectory, reflection spot and the difference of non-reflective point are come, then only utilize image-forming condition at reflection spot place, eliminate the low frequency noise produced in reverse-time migration process, there is very high guarantor's width.

The reverse-time migration formation method that the embodiment of the present invention provides, maintains inner wave field and calculates the good Concurrent Feature had, and non-being everlasting is adapted at GPU/CPU heterogeneous platform carries out, and therefore can improve the counting yield of reverse-time migration greatly.

Embodiment two

In order to test Stability and veracity of the present invention, the present embodiment is tested BP most typical in geophysics circle (BritishPetroleum, BP) mathematical model.Fig. 3 is the process flow diagram of a kind of reverse-time migration formation method that the present embodiment provides, and as shown in Figure 3, reverse-time migration formation method comprises the steps:

S301, the earthquake big gun record obtained by BP forward modeling is loaded into work area.

S302, utilizes effective denoising method, and the various noises in seismologic record are removed in substep point territory, are then again drawn into big gun territory.

S303, provides accurately for just drilling the speed-depth model of BP mathematical model as reverse-time migration of single shot record.

S304, the forward wave that GPU/CPU heterogeneous platform realizes the earthquake list big gun data that step S302 exports spreads to inverse time extrapolation outside the venue, and stores the wave field information of each time step.

S305, according to wave field separation method provided by the invention, the wave field stored step S304 carries out the separation of uplink and downlink ripple.

S306, utilizes reverse-time migration image-forming condition provided by the invention, carries out reverse-time migration imaging, and export final reverse-time migration imaging section to the focus after separation and geophone station wave field.

The reverse-time migration imaging results that the imaging results obtain the reverse-time migration image-forming condition that application the present invention mentions and traditional correlation Condition obtain compares, can learn, the imaging results that the image-forming condition utilizing the embodiment of the present invention to provide obtains obviously is better than the imaging results that traditional image-forming condition obtains, particularly more powerful to the conformation identification ability above strong reflection interface.

In embodiments of the present invention, in order to test universality of the present invention, particularly for the validity of field actual acquisition data, have chosen the measured data of 150 square kilometres of geologicstructure area under certain complicated earth surface, intricately and having carried out reverse-time migration test.According to above-mentioned steps, adopt reverse-time migration image-forming condition provided by the present invention, the imaging results obtained, by itself and the traditional reverse-time migration image-forming condition of employing, the migration result after the denoising obtained contrasts.Can see, adopt the image-forming condition that the present invention mentions, the epi-tectonic imaging for data is more accurate, and adds guarantor's width of data.For the recognition capability of steep dip structure, be also obviously better than the imaging results adopting traditional reverse-time migration image-forming condition to obtain.

The reverse-time migration formation method that the embodiment of the present invention provides, compared with traditional reverse-time migration image-forming condition, maximum advantage is to which overcome the defect that traditional reverse-time migration image-forming condition can produce the low frequency noise of a large amount of strong amplitude, directly in the process utilizing image-forming condition, just omit low frequency noise item, do not lose effective seismic signal, therefore there is higher data and protect width; Meanwhile, reverse-time migration image-forming condition provided by the invention, maintains inner wave field and calculates the good Concurrent Feature had, and non-being everlasting is adapted at GPU/CPU heterogeneous platform carries out, and therefore can improve the counting yield of reverse-time migration greatly.

Embodiment three

Fig. 4 is a kind of reverse-time migration imaging device module map that the embodiment of the present invention provides, and reverse-time migration imaging device adopts the method as described in embodiment one to generate reverse-time migration imaging section, and as shown in Figure 4, reverse-time migration imaging device comprises:

Wave field information acquisition unit 401, for obtaining source wavefield information and geophone station wave field information.

In embodiments of the present invention, wave field information acquisition unit 401 can also comprise:

Pretreatment module, for obtaining single big gun data, and carries out prestack preprocessing to single big gun data;

Extrapolation process module, the forward wave for the single big gun data exported prestack preprocessing spreads to inverse time extrapolation outside the venue, obtains source wavefield information and the geophone station wave field information of each time step.

Wave field separation unit 402, for according to obtain source wavefield information and geophone station wave field information, source wavefield being separated into focus upstream wave field and focus down-going wave fields, is geophone station upstream wave field and geophone station down-going wave fields by geophone station wave field separation.

In embodiments of the present invention, source wavefield is separated into focus upstream wave field and focus down-going wave fields by Fourier transform by wave field separation unit 402, is geophone station upstream wave field and geophone station down-going wave fields by geophone station wave field separation.

Image-generating unit 403, for carrying out reverse-time migration imaging processing to the source wavefield after separation and geophone station wave field, obtains reverse-time migration imaging section.

In embodiments of the present invention, described image-generating unit 403 comprises:

Time domain modular converter, for by be separated after source wavefield and geophone station wave-field conversion to time domain, obtain the time domain image-forming condition of reverse-time migration;

Reverse-time migration image-forming module, carries out reverse-time migration imaging for the time domain image-forming condition according to described reverse-time migration to the focus after separation and geophone station wave field, generates reverse-time migration imaging section.

The reverse-time migration imaging device that the embodiment of the present invention provides, along wave trajectory, reflection spot and the difference of non-reflective point are come, then only utilize image-forming condition at reflection spot place, eliminate the low frequency noise produced in reverse-time migration process, there is very high guarantor's width.

The reverse-time migration imaging device that the embodiment of the present invention provides, maintains inner wave field and calculates the good Concurrent Feature had, and non-being everlasting is adapted at GPU/CPU heterogeneous platform carries out, and therefore can improve the counting yield of reverse-time migration greatly.

Above-described embodiment; object of the present invention, technical scheme and beneficial effect are further described; be understood that; the foregoing is only the specific embodiment of the present invention; the protection domain be not intended to limit the present invention; within the spirit and principles in the present invention all, any amendment made, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (6)

1. a reverse-time migration formation method, is characterized in that, described method comprises:

Obtain source wavefield information and geophone station wave field information;

According to the source wavefield information obtained and geophone station wave field information, source wavefield being separated into focus upstream wave field and focus down-going wave fields, is geophone station upstream wave field and geophone station down-going wave fields by geophone station wave field separation;

Reverse-time migration imaging processing is carried out to the source wavefield after separation and geophone station wave field, obtains reverse-time migration imaging section;

Described acquisition source wavefield information and geophone station wave field information comprise:

Obtain single big gun data, and prestack preprocessing is carried out to single big gun data;

Inverse time extrapolation is spreaded to outside the venue to the forward wave of single big gun data that prestack preprocessing exports, obtains source wavefield information and the geophone station wave field information of each time step.

2. reverse-time migration formation method according to claim 1, is characterized in that, described is separated into focus upstream wave field and focus down-going wave fields by source wavefield, is that geophone station upstream wave field and geophone station down-going wave fields comprise by geophone station wave field separation:

By Fourier transform, source wavefield being separated into focus upstream wave field and focus down-going wave fields, is geophone station upstream wave field and geophone station down-going wave fields by geophone station wave field separation.

3. reverse-time migration formation method according to claim 1, is characterized in that, described to be separated after source wavefield and geophone station wave field carry out reverse-time migration imaging processing, obtain reverse-time migration imaging section and comprise:

By be separated after source wavefield and geophone station wave-field conversion to time domain, obtain the time domain image-forming condition of reverse-time migration;

Time domain image-forming condition according to described reverse-time migration carries out reverse-time migration imaging to the focus after separation and geophone station wave field, generates reverse-time migration imaging section.

4. a reverse-time migration imaging device, is characterized in that, described device comprises:

Wave field information acquisition unit, for obtaining source wavefield information and geophone station wave field information;

Wave field separation unit, for according to obtain source wavefield information and geophone station wave field information, source wavefield being separated into focus upstream wave field and focus down-going wave fields, is geophone station upstream wave field and geophone station down-going wave fields by geophone station wave field separation;

Image-generating unit, for carrying out reverse-time migration imaging processing to the source wavefield after separation and geophone station wave field, obtains reverse-time migration imaging section;

Described wave field information acquisition unit comprises:

Pretreatment module, for obtaining single big gun data, and carries out prestack preprocessing to single big gun data;

Extrapolation process module, the forward wave for the single big gun data exported prestack preprocessing spreads to inverse time extrapolation outside the venue, obtains source wavefield information and the geophone station wave field information of each time step.

5. reverse-time migration imaging device according to claim 4, it is characterized in that, source wavefield is separated into focus upstream wave field and focus down-going wave fields by Fourier transform by described wave field separation unit, is geophone station upstream wave field and geophone station down-going wave fields by geophone station wave field separation.

6. reverse-time migration imaging device according to claim 4, is characterized in that, described image-generating unit comprises:

Time domain modular converter, for by be separated after source wavefield and geophone station wave-field conversion to time domain, obtain the time domain image-forming condition of reverse-time migration;

Reverse-time migration image-forming module, carries out reverse-time migration imaging for the time domain image-forming condition according to described reverse-time migration to the focus after separation and geophone station wave field, generates reverse-time migration imaging section.