CN106842308A - A kind of non-horizontal earth's surface direct continuation beam offset method in seismic prospecting - Google Patents

Abstract

The direct continuation beam offset method of non-horizontal earth's surface in seismic prospecting disclosed by the invention, including:Obtain the true earth's surface elevation of non-horizontal and modeling speed；Big gun record, elevation and velocity field file are read in, the sampling of frequency band, initial beamwidth and ray is determined；Single Shu Jinhang is imaged using earth's surface elevation and velocity field；All beam imaging results superpositions obtain single-shot imaging results；All single-shot imaging results superpositions obtain data imaging result；The final non-horizontal earth's surface beam migration result of output.This method solve conventional method（The telogenesis picture of base-level correction+flatly）The time difference and amplitude distortion between the road that non-horizontal earth's surface exploratory area is caused seismic wave field, fully can more accurately reappear the true picture of underground medium using the propagating characteristic of non-horizontal earth's surface seismic wave.

Description

A kind of non-horizontal earth's surface direct continuation beam offset method in seismic prospecting

Technical field

It is specifically a kind of to be applied to non-horizontally the present invention relates to oil-gas exploration seismic data processing technology field Table section earthquake data before superposition is used for the method for realizing depth migration.

Prior art

Of both non-horizontal earth's surface exploratory area (including mountain front, loess tableland, desert etc.) imaging is primarily present Problem：One is big surface relief, and shallow velocity structure is changeable；Two is complicated subsurface structure, fault fold etc. Development, attitude of stratum is changeable, and this causes the seismic data signal to noise ratio in such exploratory area low and between seismic channel Time difference change is violent, and very big difficulty is brought to seismic imaging.At present, non-horizontal earth's surface exploratory area earthquake The conventional method of data imaging can be described as：Base-level correction is carried out first, by seismic data corrections to water Flat datum level or the less floating datum of rising and falling, then application level earth's surface Kirchhoff prestack depths Offset method is imaged, and this method can introduce new seismic channel time difference shadow due to the error of filling speed Ring the accuracy of imaging.Additionally, there have correlation to carry out non-horizontal earth's surface using reverse-time migration operator both at home and abroad to be direct The pre-stack depth migration research of imaging, but because actual seismic data signal to noise ratio is low, speed accuracy is poor, The restriction of wave equation factor such as mesh generation and BORDER PROCESSING difficulty when non-horizontal earth's surface is described, it is in addition inverse Hour offset amount of calculation is huge, it is difficult to the popularization and application in actual production.Therefore, development is directed to non-horizontal The practical offset method of earth's surface exploratory area direct imaging is most important.

" beam " is a kind of distillation that ray theory characterizes seismic wave field, and ray class is replaced using Local plane wave High-frequency ray in skew " without width ", offsets beam and has the skew of ray class concurrently with the skew of wave equation class Advantage：Continue Kirchhoff calculations of offset efficiency high, realize convenient, good to non-horizontal earth's surface fitting Ying Xing, and there is the propagation precision close to wave equation migration during wave field extrapolation, this causes beam Skew turns into the potentiality technology of non-horizontally table exploratory area imaging.

The content of the invention

The present invention seeks to regarding to the issue above, provide the direct continuation of non-horizontal earth's surface in a kind of seismic prospecting Beam offset method.The method directly carries out Local plane wave using earth's surface elevation and near-surface velocity from true earth's surface Decompose, the hi-fi of amplitude wave field operator of application beam integral representation in migration process carries out Continuation Imaging, solve often Rule method (base-level correction+flatly telogenesis picture) is between the road that non-horizontal earth's surface exploratory area is caused seismic wave field The time difference and amplitude distortion, fully can more accurately reappear using the propagating characteristic of non-horizontal earth's surface seismic wave The true picture of underground medium.

The direct continuation beam offset method of non-horizontal earth's surface in seismic prospecting of the invention includes herein below：Obtain The negated true earth's surface elevation of level and modeling speed；Big gun record, elevation and velocity field file are read in, it is determined that frequency The sampling of band, initial beamwidth and ray；Single Shu Jinhang is imaged using earth's surface elevation and velocity field；All beams Imaging results superposition obtains single-shot imaging results；All single-shot imaging results superpositions obtain data imaging result； The final non-horizontal earth's surface beam migration result of output.

Such scheme is further included：

Seismic data is gathered in seismic prospecting field work area using focus and wave detector, and pre- place is carried out to data Reason and conventional treatment；

(1) velocity modeling is carried out to seismic data, the true earth's surface elevation of non-horizontal and prestack depth domain speed is obtained ；

(2) actual big gun collection record, the true earth's surface elevation of non-horizontal and the number of prestack depth domain velocity field three are read in According to file, it is determined that frequency band range (generally 10Hz~50Hz) is imaged, then according to the geometric average of velocity field Value and reference frequency determine beam original width, finally using frequency band range and original width determine interfascicular every and Initial ray parameter space；

(3) then entered for each beam every a series of " beam " is divided into according to beam original width and interfascicular The following operation of row：Earthquake big gun collection is recorded according to formula (1) institute using relief surface elevation and near-surface velocity Showing carries out adding window local dip superposition, is utilized respectively kinematics and kinetics ray-tracing calculates focus and detection Information when walking and amplitude information of " beam " of outgoing, obtain focus to the continuation wave field of geophone station at device position D(ω,x,x_s) and geophone station to focus continuation wave field U (ω, x, x_s), then by corresponding continuation wave field slant stack Deconvolution image-forming condition shown in road application formula (2) is imaged, and completes a skew for beam；

Wherein, G (L, ω, p_Lx) centered on be located at_LPlace " beam " interior earthquake record adding window local dip superposition, ω and ω_rRespectively frequency and reference frequency, Ω are non-horizontally surface, and β is " beam " angle of emergence, and α is earth's surface Inclination angle, U (ω, x_r,x_s) it is geophone station x_rTo focal point x_sContinuation wave field, w₀It is beam original width, p_LxAnd p_Lz It is the x and z-component of the initial slowness of beam line, h is geophone station x_rWith beam center_LDepth displacement；R(x,x_s) It is into picture value, D (ω, x, x_s) and U (ω, x, x_s) focus is respectively to the continuation wave field and geophone station of geophone station to focus Continuation wave field, π is pi, and * represents conjugation.

(4) each " beam " is circulated, obtains the migration result of all beams, single big gun is obtained after superposition Collect the imaging results of record；

(5) each single shot record is circulated, obtains the migration result of all single-shots, obtain whole after superposition The imaging results of individual data.

Invention effect

Firstth, Local plane wave decomposition can be directly carried out using the true earth's surface elevation of non-horizontal and near-surface velocity, And the continuation operator of hi-fi of amplitude is added, solve conventional method (base-level correction+flatly telogenesis picture) and exist The time difference and amplitude distortion, more accurately reappear underground between the road that non-horizontal earth's surface exploratory area is caused seismic wave field The true picture of medium；

Secondth, continued Kirchhoff calculations of offset efficiency high, realize it is convenient, good to non-horizontal earth's surface Adaptability, and there is the propagation precision close to wave equation migration during wave field extrapolation, can be compared with Non-horizontal earth's surface exploratory area imaging effect difference is solved the problems, such as well or can not be imaged；

3rd, computational efficiency is high, and under same computing resource, computational efficiency is improved compared to reverse-time migration More than half.

Brief description of the drawings

A kind of concrete operations flow chart of embodiment of Fig. 1 the inventive method；

Fig. 2 is just drilling big gun collection record；

Fig. 3 is just drilling the non-horizontal earth's surface elevation of big gun collection record；

Fig. 4 is just drilling the migration before stack velocity field of big gun collection record；

Fig. 5 is just drilling big gun collection and is recording corresponding non-horizontal earth's surface beam migration result；

The big gun collection record of Fig. 6 actual seismic data；

The non-horizontal earth's surface elevation of Fig. 7 actual seismic data；

The migration before stack velocity field of Fig. 8 actual seismic data；

The corresponding non-horizontal earth's surface beam migration result of Fig. 9 actual seismic data.

Embodiment

The actual seismic data money that big gun collection record and field acquisition are obtained just is drilled using what model value simulation was obtained Material, aligned according to operating procedure of the invention drill big gun collection record and actual seismic data processed, illustrate this The application effect of invention.

The detailed technology operating procedure of the invention is as shown in Figure 1.Mainly include following steps：(1) field Collection data and conventional treatment；(2) the true earth's surface elevation of non-horizontal and modeling speed are obtained；(3) read in Big gun record, elevation and velocity field file, determine the sampling of frequency band, initial beamwidth and ray；(4) earth's surface is utilized Elevation and velocity field are imaged to single Shu Jinhang；(5) all beam imaging results superpositions obtain single-shot imaging results； (6) all single-shot imaging results superpositions obtain data imaging result；(7) final non-horizontal earth's surface beam is exported Migration result.

Just drilling big gun collection record embodiment 1：

(1) seismic data is gathered in seismic prospecting field work area using focus and wave detector, Fig. 2 show profit The big gun collection for obtaining is simulated with forward modeling to record；(2) velocity modeling is carried out to seismic data, non-horizontal is obtained True earth's surface elevation (Fig. 3) and prestack depth domain velocity field (Fig. 4)；(3) read in actual big gun collection record, it is non- Three data files of the true earth's surface elevation of level and prestack depth domain velocity field, the imaging frequency band model for selecting herein It is minimum frequency 10Hz to enclose, peak frequency 50Hz, and the geometrical mean and reference frequency according to velocity field determine Beam original width be 468m, determine that interfascicular is divided into 418m using frequency band range and original width；(4) basis Then beam original width and interfascicular proceed as follows every a series of " beam " is divided into for each beam：Profit Earthquake big gun collection is recorded with relief surface elevation and near-surface velocity according to carrying out adding window part formula (1) Suo Shi Slant stack, is utilized respectively kinematics and kinetics ray-tracing calculates outgoing at focus and detector position Information when walking and amplitude information of " beam ", obtain focus to the continuation wave field and geophone station of geophone station to focus Continuation wave field, then by the deconvolution shown in corresponding continuation wave field slant stack road application formula (2) into Slice part is imaged, and completes a skew for beam；(5) each " beam " is circulated, is owned The migration result of beam, obtains the imaging results of single big gun collection record after superposition；(6) each single shot record is entered Row circulation, obtains the migration result of all single-shots, and the imaging results that whole data are obtained after superposition are displayed in Fig. 5 In, it can be seen that：The non-horizontal earth's surface migration result that the inventive method is obtained, the imaging for having suppressed shallow-layer is made an uproar Sound, improves the imaging precision of near surface, and the imaging energy of mid-deep strata is maintained.Shallow mid-deep strata Geological structure layer position imaging clearly, position and depth are correct, demonstrate the accuracy of the inventive method.

Actual seismic data embodiment 2：(1) gathered in seismic prospecting field work area using focus and wave detector Seismic data, such as Fig. 6, and data is pre-processed and conventional treatment；(2) speed is carried out to seismic data Modeling, obtains the true earth's surface elevation (Fig. 7) of non-horizontal and prestack depth domain velocity field (Fig. 8)；(3) read in Actual big gun collection record, three data files of the true earth's surface elevation of non-horizontal and prestack depth domain velocity field, herein The imaging frequency band range of selection is minimum frequency 10Hz, peak frequency 50Hz, according to the geometric average of velocity field Value and reference frequency determine beam original width be 380m, using frequency band range and original width determine interfascicular every It is 340m；(4) according to beam original width and interfascicular every a series of " beam " is divided into, then for each beam Proceed as follows：Earthquake big gun collection is recorded according to formula (1) using relief surface elevation and near-surface velocity It is shown to carry out adding window local dip superposition, it is utilized respectively kinematics and kinetics ray-tracing calculates focus and inspection Information when walking and amplitude information of " beam " of outgoing, obtain focus to the continuation ripple of geophone station at ripple device position And geophone station to focus continuation wave field, then by corresponding continuation wave field slant stack road application formula (2) Shown deconvolution image-forming condition is imaged, and completes a skew for beam；(5) each " beam " is carried out Circulation, obtains the migration result of all beams, and the imaging results of single big gun collection record are obtained after superposition；(6) it is right Each single shot record is circulated, and obtains the migration result of all single-shots, obtained after superposition whole data into Picture result, as shown in Figure 9.

Further demonstrated that by above-described embodiment：The non-horizontal earth's surface migration result that the inventive method is obtained, it is shallow Layer imaging noise is few, and construction is clear, and the main tectonic level of mid-deep strata has also obtained preferable imaging, skew knot Fruit hi-fi of amplitude is good, and layer position excursions depths are accurate, demonstrate the application effect of the inventive method.

Claims (2)

1. the direct continuation beam offset method of non-horizontal earth's surface in a kind of seismic prospecting, it is characterised in that including:Obtain The negated true earth's surface elevation of level and modeling speed；Big gun record, elevation and velocity field file are read in, it is determined that frequency The sampling of band, initial beamwidth and ray；Single Shu Jinhang is imaged using earth's surface elevation and velocity field；All beams Imaging results superposition obtains single-shot imaging results；All single-shot imaging results superpositions obtain data imaging result； The final non-horizontal earth's surface beam migration result of output.

2. the direct continuation beam offset method of non-horizontal earth's surface in seismic prospecting according to claim 1, It is characterized in that including:

(1) velocity modeling is carried out to seismic data, the true earth's surface elevation of non-horizontal and prestack depth domain speed is obtained ；

(2) actual big gun collection record, the true earth's surface elevation of non-horizontal and the number of prestack depth domain velocity field three are read in According to file, it is determined that imaging frequency band range is 10Hz~50Hz, the then geometrical mean according to velocity field and reference Frequency determines beam original width, finally using frequency band range and original width determine interfascicular every and initial ray Parameter space；

(3) then entered for each beam every a series of " beam " is divided into according to beam original width and interfascicular The following operation of row：Earthquake big gun collection is recorded according to formula (1) institute using relief surface elevation and near-surface velocity Showing carries out adding window local dip superposition, is utilized respectively kinematics and kinetics ray-tracing calculates focus and detection Information when walking and amplitude information of " beam " of outgoing, obtain focus to the continuation wave field of geophone station at device position D(ω,x,x_s) and geophone station to focus continuation wave field U (ω, x, x_s), then by corresponding continuation wave field slant stack Deconvolution image-forming condition shown in road application formula (2) is imaged, and completes a skew for beam；

$G(L,\mathrm{\ω},p_{Lx})=\sqrt{\mathrm{\ω}/{\mathrm{\ω}}_r}\∫d\mathrm{\Ω}cos(\mathrm{\β}-\mathrm{\α})U(\mathrm{\ω},x_r,x_s)\exp \[-\frac{\mathrm{\ω}{(x_r-L)}^2}{2{\mathrm{\ω}}_r{w}_0^2}\]\exp \[i\mathrm{\ω}\left(p_{Lx}\right(x_r-L)+p_{Lz}h)\]---\left(1\right)$

$R(x,x_s)=\frac{1}{2\mathrm{\π}}\∫d\mathrm{\ω}\frac{U(\mathrm{\ω},x,x_s)D^{*}(\mathrm{\ω},x,x_s)}{D(\mathrm{\ω},x,x_s)D^{*}(\mathrm{\ω},x,x_s)}---\left(2\right)$

Wherein, G (L, ω, p_Lx) centered on be located at L place " beam " interior earthquake record adding window local dip superposition, ω with ω_rRespectively frequency and reference frequency, Ω are non-horizontally surface, and β is " beam " angle of emergence, and α is earth's surface Inclination angle, U (ω, x_r,x_s) it is geophone station x_rTo focal point x_sContinuation wave field, w₀It is beam original width, p_LxAnd p_Lz It is the x and z-component of the initial slowness of beam line, h is geophone station x_rWith the depth displacement of beam center L；R(x,x_s) It is into picture value, D (ω, x, x_s) and U (ω, x, x_s) focus is respectively to the continuation wave field and geophone station of geophone station to focus Continuation wave field, π is pi, and * represents conjugation；

(4) each " beam " is circulated, obtains the migration result of all beams, single big gun is obtained after superposition Collect the imaging results of record；

(5) each single shot record is circulated, obtains the migration result of all single-shots, obtain whole after superposition The imaging results of individual data.