CN102692651A - Preliminary wave residual static correction method with space-variant velocity - Google Patents

Abstract

The present invention provides a preliminary wave residual static correction method with space-variant velocity. A linear correction and first-break picking are carried out on a single shot, data recorded in a preliminary wave is selected to a common midpoint gather area, according to a sequence of a line number and a common midpoint gather number and a line interval parameter, linear speed fitting is carried out according to a first break time of common midpoint gather, a speed analysis point velocity is obtained, space-variant linear velocity correction is carried out, residual static correction values of a shot point and a receiving point are solved on a corrected first break time, and static correction is carried out. The method can be applied to conditions that a data signal-to-noise ratio is poor, the first break time is not easy to acquire, and there is no reliable refractive layer data, the efficiency of the method is higher than that of a conventional refractive wave, tomographic static correction efficiency is high, a lot of time can be saved, an anti-noise capacity is strong, an application effect is stable, and the use of the method is convenient.

Description

The primary wave residual static corrections of speed space-variant

Technical field

The present invention relates to the geophysical survey seismic data processing technique, belong to the technological category of static correction in the seismic data processing procedure, is a kind of primary wave residual static corrections of speed space-variant specifically.

Background technology

Need be in the land earthquake data acquisition to the seismic data static corrections processing, present conventional first arrival refraction static correction method is at the enterprising line linearity correction of original single big gun, carries out first arrival then and picks up, first break time is charged to trace header, exports a first arrival file simultaneously.The first break time file has been arranged, just can carry out conventional first arrival refraction static correction, conventional first arrival refraction static correction generally is refractive wave static correction or chromatography static correction; For refractive wave static correction; The first break time from same refractor is picked up in requirement on the big gun collection, when directly calculating high-velocity bed speed and postponing according to refraction first break time and refraction wave whilst on tour formula, this method requires relatively harshness; Requirement has refraction wave; First arrival is picked up easily, and for complicated earth surface low signal-to-noise ratio data situation, this requirement is difficult to satisfy.For the chromatography static correction, except picking up accurate first break time, the more important thing is operational efficiency problem and inversion accuracy problem.

Especially by land in the earthquake data acquisition; Owing to reasons such as face of land complicacy and subsurface geologic structures, the geological data signal to noise ratio (S/N ratio) of collection is extremely low, and particularly the top layer lateral speed change is big; Cause first arrival complicated; Unstable refraction, a little less than reflected signal also reached, conventional first arrival refraction static correction method missed one's aim.

Summary of the invention

The object of the invention provides the primary wave residual static corrections of the speed space-variant that a kind of convenience is simple and direct, precision is high.

The present invention realizes through following steps:

1) acquiring seismic data carries out data analysis to original single big gun data, and affirmation need be done first arrival refraction static correction;

The described data analysis of step 1) is that original single big gun data and face of land elevation are together shown, analyzes the corresponding relation of elevation and first break time, and elevation change is big; The big data of face of land speed horizontal change; First arrival just changes greatly, and signal to noise ratio (S/N ratio) is low, need do first arrival refraction static correction.

2) pick up in the enterprising line linearity correction of single big gun, first arrival, will pick up the result and charge to trace header, keep the geological data that note has first break time;

Step 2) to pick up be to provide a fixing linear speed linearity correction is carried out in first arrival for described correction and first arrival, distributes according near the noise the first arrival and confirm the mode that first arrival is picked up.

The mode that described first arrival is picked up is that noise ratio is less before first arrival, and the primary wave energy is strong, selects the mode of picking up in batches; When noise is big, a little less than the primary wave energy, first arrival is unclear, picks up through interactive means.

3) be sorted into the CMP gather territory to the data of charging to the primary wave time, order and line spacing parameter by wire size and CMP gather number obtain CMP road collection;

The described CMP gather of step 3) is a big bin road collection.

4) do the linear speed match according to the first break time on the CMP gather, obtain the velocity analysis spot speed;

Described the picking up in the enterprising line speed match of first break time of step 4) is to choose straight line wantonly at the first arrival position of data; The method of employing fitting a straight line is obtained the linear speed of straight line; Carry out mutual linearity correction then, if smoothing, the speed of preserving each space-variant point.

5) to step 2) keep and remember that the geological data that first break time is arranged carries out the space-variant linear speed and proofreaies and correct;

The described space-variant linear speed of step 5) school is to proofread and correct with linear speed updating formula X/V, and X is an offset distance in the formula, and V is the space-variant spot speed after the match of step 4) speed.

6) first break time of carrying out after the space-variant linear speed is proofreaied and correct is found the solution the residual static correction amount of shot point and acceptance point with Gauss-Sai Deer alternative manner;

The residual static correction amount that step 6) is found the solution shot point and acceptance point adopts following method:

First break time is: T ' _Ijk=S _i+ R _j+ G _k+ K _kX _Ij

S wherein _iBe the static correction value of i shot point, R _jBe the static correction value of j acceptance point, G _kBeing the structure item value of k CMP, is the DC component of static correction value in the CMP road collection, K _kIt is the residue linear speed of k CMP; Utilize least square method to find the solution this equation, the travel-times of seismic first breaks T that is picked up then _IjkWith model whilst on tour T ' _IjkBetween the quadratic sum of difference minimum, obtain shot point and acceptance point residual static correction amount through iteration.

7) use shot point and the acceptance point residual static correction amount obtained of step raw data is carried out static correction.

The present invention is applicable to the data poor signal to noise, and first break time is difficult for picking up, and does not have under the reliable refractor data conditions, and big like surface relief, lateral speed change is big, and static correction value is asked for the place of difficulty.The conventional refraction wave of efficiency ratio of the present invention, chromatography static correction efficient is high, can save the plenty of time, and anti-noise ability is strong, and effect is stable, and is easy to use.

Description of drawings

Fig. 1 is original single big gun and elevation curve display;

Fig. 2 is the single big gun that has first break time;

Fig. 3 is the linear speed analysis site location drawing;

Fig. 4 is that linear speed is picked up;

Fig. 5 is the linear speed correction test;

Fig. 6 is that the single big gun after the static correction shows.

Embodiment

Specify the present invention below in conjunction with accompanying drawing.

1) acquiring seismic data carries out data analysis to original single big gun data, and affirmation need be done first arrival refraction static correction;

Data shown in Figure 1 are that original single big gun data and face of land elevation (top curve) are together shown; Through analyzing the corresponding relation of elevation and first break time; The discovery elevation change is big, and the discrepancy in elevation reaches the big data of 200 meter indicated airspeed degree horizontal change, and first arrival just changes greatly; Signal to noise ratio (S/N ratio) is low, need do first arrival refraction static correction.

2) pick up in the enterprising line linearity correction of single big gun, first arrival, will pick up the result and charge to trace header, keep the geological data that note has first break time, the first break time that first arrival is picked up is so long as primary wave gets final product, and it is to select according to the data situation that first arrival is picked up, as:

Noise ratio is less before the first arrival of Fig. 1, and the primary wave energy is strong, so select the mode of picking up in batches.

Fig. 2 is the result who picks up in batches, and what the figure mid point was represented is first break time, and first break time is charged in the trace header.

The first arrival program of picking up provides a fixing linear speed linearity correction is carried out in first arrival, selects the first arrival pick-up method according near the noise distribution situation the first arrival, if noise ratio is less before the first arrival, the primary wave energy is strong, selects to pick up in batches to get final product.

3) be sorted into the CMP gather territory to single big gun data of charging to the primary wave time, order and line spacing parameter by wire size and CMP gather number obtain common midpoint (CMP) road collection;

Position shown in Fig. 3 intersection point is the CMP gather position.Order by wire size and CMP number is read in, and the line spacing parameter and the CMP spacing parameter that provide according to the user carry out sorting, can obtain the CMP road collection that needs.Described CMP road collection is a big bin road collection.

4) do the linear speed match according to the first break time on the CMP gather, obtain each analysis site speed.

In the enterprising line speed match of first break time is optional straight line at the first arrival position of data, and the method for employing fitting a straight line is obtained the linear speed of straight line, carries out mutual linearity correction then, if smoothing, the speed of preserving each space-variant point.

5) to step 2) geological data that keeps note and have first break time puts linear speed with space-variant and proofreaies and correct the speed linear interpolation between the space-variant point.Like Fig. 4, Fig. 5.

It is to proofread and correct with linear speed updating formula X/V that the described space-variant linear speed of step 5) is proofreaied and correct, and X is an offset distance in the formula, and V is the space-variant spot speed after the match of step 4) speed.

The step 4) linear speed not is that all data are carried out the linear speed analysis when analyzing, but on the given road collection of user, carries out, and this step will be carried out linearity correction to all data, as the input in the 6th step.

6) first break time of carrying out after the space-variant linear speed is proofreaied and correct is found the solution the residual static correction amount of shot point and acceptance point with Gauss-Sai Deer alternative manner;

The residual static correction amount that step 6) is found the solution shot point and acceptance point adopts following method:

First break time is: T ' _Ijk=S _i+ R _j+ G _k+ K _kX _Ij

S wherein _iBe the static correction value of i shot point, R _jBe the static correction value of j acceptance point, G _kBeing the structure item value of k CMP, is the DC component of static correction value in the CMP road collection, K _kIt is the residue linear speed of k CMP; Utilize least square method to find the solution this equation, the travel-times of seismic first breaks T that is picked up then _IjkWith model whilst on tour T ' _IjkBetween the quadratic sum of difference minimum, obtain shot point and acceptance point residual static correction amount through iteration.

Least square method is found the solution this equation process:

$E=\underset{\mathrm{ijk}}{\mathrm{\Σ}}{(T_{\mathrm{ijk}}^{\′}-T_{\mathrm{ijk}})}^2\→\mathrm{Min}$

Respectively to S _i, R _j, G _k, K _kAsk local derviation

$\frac{\∂E}{\∂S}=\frac{\∂E}{\∂R}=\frac{\∂E}{\∂G}=\frac{\∂E}{\∂K}=0$

Can be write following formula as following form:

$G_k^{\left(v\right)}=\frac{\underset{i,j,k}{\mathrm{\Σ}}\{T_{\mathrm{ijk}}-S_i^{(v-1)}-R_j^{(v-1)}-K_i^{(v-1)}{X}_{\mathrm{ij}}\}}{N_k}$

$K_k^{\left(v\right)}=\frac{\underset{i,j,k}{\mathrm{\Σ}}\{T_{\mathrm{ijk}}-S_i^{(v-1)}-R_j^{(v-1)}-G_k^{\left(v\right)}\}*X_{\mathrm{ij}}}{N_i\mathrm{\Σ}{X}_{\mathrm{ij}}^2}$

$S_i^{\left(v\right)}=\frac{\underset{j,k,i}{\mathrm{\Σ}}\{T_{\mathrm{ijh}}-R_j^{(v-1)}-G_k^{\left(v\right)}-K_i^{\left(v\right)}{X}_{\mathrm{ij}}\}}{N_i}$

$R_j^{\left(v\right)}=\frac{\underset{i,k,j}{\mathrm{\Σ}}\{T_{\mathrm{ijh}}-S_i^{\left(v\right)}-G_k^{\left(v\right)}-K_i^{\left(v\right)}{X}_{\mathrm{ij}}\}}{N_j}$

Wherein (v) being the v time iteration result, (v-1) is the v-1 time iteration result, i.e. the v time last iteration result.

7) use shot point and the acceptance point residual static correction amount obtained of step original shot gather data is carried out static correction.

The present invention is applicable to the data poor signal to noise, and first break time is difficult for picking up, and does not have under the reliable refractor data conditions, and big like surface relief, lateral speed change is big, and static correction value is asked for the place of difficulty.With Fig. 1 contrast, Fig. 6 static correction effect is fine.

The conventional refraction wave of efficiency ratio of the present invention, chromatography static correction efficient is high, can save the plenty of time.The present invention adopts main road collection match first arrival speed, and anti-noise ability is strong, and effect is stable, and is easy to use.

Claims (8)

1. the primary wave residual static corrections of a speed space-variant, characteristics are to realize through following steps:

1) acquiring seismic data carries out data analysis to original single big gun data, and affirmation need be done first arrival refraction static correction;

2) pick up in the enterprising line linearity correction of single big gun, first arrival, will pick up the result and charge to trace header, keep the geological data that note has first break time;

3) be sorted into the CMP gather territory to the data of charging to the primary wave time, order and line spacing parameter by wire size and CMP gather number obtain CMP road collection;

4) do the linear speed match according to the first break time on the CMP gather, obtain the velocity analysis spot speed;

5) to step 2) keep and remember that the geological data that first break time is arranged carries out the space-variant linear speed and proofreaies and correct;

6) first break time of carrying out after the space-variant linear speed is proofreaied and correct is found the solution the residual static correction amount of shot point and acceptance point with Gauss-Sai Deer alternative manner;

7) use shot point and the acceptance point residual static correction amount obtained of step raw data is carried out static correction.

2. method according to claim 1; Characteristics are that the described data analysis of step 1) is that original single big gun data and face of land elevation are together shown, analyze the corresponding relation of elevation and first break time, and elevation change is big; The big data of face of land speed horizontal change; First arrival just changes greatly, and signal to noise ratio (S/N ratio) is low, need do first arrival refraction static correction.

3. method according to claim 1, characteristics are steps 2) described correction and first arrival are picked up is to provide a fixing linear speed linearity correction is carried out in first arrival, and distribute according near the noise the first arrival and confirm the mode that first arrival is picked up.

4. method according to claim 3, characteristics are that the mode that described first arrival is picked up is that noise ratio is less before first arrival, and the primary wave energy is strong, selects the mode of picking up in batches; When noise is big, a little less than the primary wave energy, first arrival is unclear, picks up through interactive means.

5. method according to claim 1, characteristics are that the described CMP gather of step 3) is a big bin road collection.

6. method according to claim 1; Characteristics are that described the picking up in the enterprising line speed match of first break time of step 4) is to choose straight line wantonly at the first arrival position of data; The method of employing fitting a straight line is obtained the linear speed of straight line; Carry out mutual linearity correction then, if smoothing, the speed of preserving each space-variant point.

7. method according to claim 1, characteristics are that the described space-variant linear speed correction of step 5) is to proofread and correct with linear speed updating formula X/V, and X is an offset distance in the formula, and V is the space-variant spot speed after the match of step 4) speed.

8. method according to claim 1, characteristics are that the residual static correction amount that step 6) is found the solution shot point and acceptance point adopts following method:

First break time is: T ' _Ijk=S _i+ R _j+ G _k+ K _kX _Ij

S wherein _iBe the static correction value of i shot point, R _jBe the static correction value of j acceptance point, G _kBeing the structure item value of k CMP, is the DC component of static correction value in the CMP road collection, K _kIt is the residue linear speed of k CMP; Utilize least square method to find the solution this equation, the travel-times of seismic first breaks T that is picked up then _IjkWith model whilst on tour T ' _IjkBetween the quadratic sum of difference minimum, obtain shot point and acceptance point residual static correction amount through iteration.

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