CN103869369B - Method for correcting interval velocity by using residue curvature - Google Patents

Abstract

The invention provides a method for correcting an interval velocity by using a residue curvature. The method comprises the steps of extracting root-mean-square velocities of m intervals from a vertical speed function, and obtaining the interval velocities of the m intervals before updating according to the extracted root-mean-square velocities of the m intervals; solving the average interval velocity of the m intervals before updating; establishing a general function about the interval velocities of the m intervals and calculating the corresponding interval velocities of the m intervals when the general function is minimal as the interval velocities of the m intervals after updating; solving the average interval velocity of the m intervals after updating; calculating the residue curvature of the m intervals after updating according to the average interval velocity of the m intervals before updating and the average interval velocity of the m intervals after updating; correcting the interval velocities of the m layers before updating by using the residue curvature of the m intervals after updating. The stable interval velocity can be obtained by adopting the method and high-frequency oscillation due to residue curvature updating is prevented.

Description

Method interval velocity being corrected using remaining curvature

Technical field

The invention belongs to oil seismic exploration field, it is mainly used in seismic prospecting data and processes and explain, more specifically Say, be related to a kind of realize stable method interval velocity being corrected using remaining curvature.

Background technology

In process of seismic data processing, interval velocity serves very important effect, the direct shadow of precision of rate pattern Ring the quality of imaging results.

At present, the method for existing correction interval velocity is to extract stack velocity from velocity function spectrum, and will be superimposed speed Degree is converted to root-mean-square（RMS）Speed, then with Dix formula, root mean sequare velocity is converted into interval velocity.In theory, the party Method is only applicable to horizontal layered earth and the situation of little geophone offset, poor anti jamming capability, stack velocity or root mean sequare velocity micro- Little change all will make remaining curvature update and produce the higher-order of oscillation.

Content of the invention

It is an object of the invention to proposing a kind of method interval velocity being corrected using remaining curvature it is achieved that stablizing Reliable instantaneous velocity calculates, it is to avoid the HFO causing because interval velocity is unstable.

An aspect of of the present present invention provides a kind of method interval velocity being corrected using remaining curvature, methods described bag Include：（a）The root mean sequare velocity of m layer is extracted from vertical speed functionWherein,Mean square for the n-th layer in m layer Root speed, n ∈ [1, m], according to the root mean sequare velocity of the m layer extractingThe interval velocity of m layer before being updatedIts In,Interval velocity for the n-th layer in m layer before updating；（b）Interval velocity to m layer before updatingIt is averaging, obtain The average interval velocity of the m layer to before updateWherein,Average layer speed for the n-th layer in m layer before updating Degree；（c）Set up interval velocity V with regard to m layer_nFunctional, wherein, V_nFor the interval velocity of the n-th layer in m layer, calculate Functional is interval velocity V of corresponding m layer during minimum_n, by interval velocity V of calculated m layer_nAs m after updating The interval velocity of layerWherein,Interval velocity for the n-th layer in m layer after updating；（d）To m layer after updating Interval velocityIt is averaging, the average interval velocity of m layer after being updatedWherein,For in m layer after updating N-th layer average interval velocity；（e）Average interval velocity according to m layer before updatingWith update after m layer average Interval velocityCalculate remaining curvature γ of m layer after updating_n, wherein, γ_nFor the n-th layer in m layer after updating Remaining curvature；（f）Remaining curvature γ using m layer after updating_nInterval velocity to m layer before updatingIt is corrected.

Alternatively, step（a）The interval velocity of the n-th layer in the middle m layer calculating before updatingFormula as follows,

Wherein,For the root mean sequare velocity of (n-1)th layer in m layer, t_nFor the time of the n-th layer in m layer, t_n-1For The time of (n-1)th layer in m layer.

Alternatively, step（b）The average interval velocity of the n-th layer in the middle m layer calculating before updatingFormula as follows,

Wherein,For the interval velocity of i-th layer in n layer before updating, z_nLayer locating depth for the n-th layer in m layer Degree, z_n-1Layer bit depth for (n-1)th layer in m layer.

Alternatively, described functional is that data item fitting expression, trend term fitting expression and smooth item matching are expressed The sum of formula.

Alternatively, the interval velocity according to m layer before updatingInterval velocity V with m layer_n, obtain data item matching table Reach formula.

Alternatively, data item fitting expression is,

Wherein, B represents data item fitting expression, Δ t_nFor the time interval of the n-th layer in m layer and (n-1)th layer, Δ t_n=t_n-t_n-1, t_nFor the time of the n-th layer in m layer, t_n-1For the time of (n-1)th layer in m layer,For in m layer The weight coefficient of the data item of n-layer, V_n-1Interval velocity for (n-1)th layer in m layer.

Alternatively, interval velocity V according to m layer_nAnd trend function, obtain trend term fitting expression.

Alternatively, the calculation expression of trend function is,

Wherein, V^trendT () represents trend function, V_aFor the instantaneous velocity on ground top layer, V_∞Instantaneous speed for infinite deep layer Degree, Δ V is the excursion of instantaneous velocity, k_aFor previously given control parameter, t is the time.

Alternatively, wherein, trend term fitting expression is,

Wherein, C represents trend term fitting expression, Δ t_nFor the time interval of the n-th layer in m layer and (n-1)th layer, Δ t_n=t_n-t_n-1, t_nFor the time of the n-th layer in m layer, t_n-1For the time of (n-1)th layer in m layer,For in m layer The weight coefficient of the trend term of n-th layer,Interval velocity V for (n-1)th layer in m layer_n-11- (τ/Δ t_n) power,For in m layer n-th layer interval velocity V_nτ/Δ t_nPower, V^trend(t_n-1+ τ) it is time t=t_n-1Becoming during+τ Potential function.

Alternatively, choose interval velocity V to m layer for the smoothing factor_nIt is smoothed, obtain smooth item matching expression Formula.

Alternatively, smooth item fitting expression is,

Wherein, D represents smooth item fitting expression,For unit characteristic number,Flat for the n-th layer in m layer The sliding factor, Δ t_nFor the time interval of the n-th layer in m layer and (n-1)th layer, Δ t_n=t_n-t_n-1, Δ t_n+1For n-th in m layer + 1 layer of time interval with n-th layer, Δ t_n+1=t_n+1-t_n, t_nFor the time of the n-th layer in m layer, t_n-1For n-th in m layer- 1 layer of time, t_n+1For the time of (n+1)th layer in m layer, V_nFor the interval velocity of the n-th layer in m layer, V_n+1For in m layer (n+1)th layer of interval velocity.

Alternatively, calculate remaining curvature γ of the n-th layer in m layer after updating_nFormula be,

The interval velocity of m layer is carried out using the method that remaining curvature is corrected to interval velocity using of the present invention Correction, makes the interval velocity of m layer after correction more accurate, is conducive to the judgement to subsurface geologic structures and pre- to oil-gas Layer Survey.

Brief description

By the detailed description carrying out below in conjunction with the accompanying drawings, above and other objects of the present invention, feature and advantage will Become more fully apparent, wherein：

Fig. 1 is the flow process of the method illustrating using remaining curvature, interval velocity to be corrected according to an embodiment of the invention Figure.

Specific embodiment

Describe embodiments of the invention next, with reference to accompanying drawing in detail.

Offer following description referring to the drawings is to help the enforcement to the present invention being limited by claim and its equivalent The comprehensive understanding of example.Including various specific detail to help understand, but these details are considered only as being exemplary.Therefore, originally Field skilled artisan will realize that without departing from the scope and spirit of the present invention, can be to reality described herein Apply example to make various changes and modifications.Additionally, for clarity and brevity, omit the description to known function and structure.

Fig. 1 is the flow process of the method illustrating using remaining curvature, interval velocity to be corrected according to an embodiment of the invention Figure.

With reference to Fig. 1, from vertical speed function, in a step 101, extract the root mean sequare velocity of m layerWherein, For the root mean sequare velocity of the n-th layer in m layer, n ∈ [1, m], according to the root mean sequare velocity of the m layer extractingUpdated The interval velocity of m front layerWherein,Interval velocity for the n-th layer in m layer before updating.

For example, various existing methods are can be utilized to extract the root mean sequare velocity of m layer from vertical speed functionWith m The time t of layer_n, t_nFor the time of the n-th layer in m layer, wherein, as n=1, in m layer (n-1)th layer of root mean sequare velocityFor the root mean sequare velocity on ground top layer, the time t of (n-1)th in m layer layer₀For the time on ground top layer, in m layer Layer bit depth z of n-1 layer₀For the layer bit depth on ground top layer, interval velocity V of (n-1)th in m layer layer₀Layer for ground top layer Speed.Here, the root mean sequare velocity on ground top layerTime t with ground top layer₀Can extract from vertical speed function and obtain.

For example, calculate the interval velocity of the n-th layer in m layer before updatingFormula as follows,

Formula（1）In,For the root mean sequare velocity of (n-1)th layer in m layer, t_n-1For (n-1)th layer in m layer when Between.

In a step 102, the interval velocity to m layer before updatingBe averaging, m layer before being updated average Interval velocityWherein,Average interval velocity for the n-th layer in m layer before updating.

For example, calculate the average interval velocity of the n-th layer in m layer before updatingFormula as follows

Formula（2）In,For the interval velocity of i-th layer in n layer before updating, z_nLayer for the n-th layer in m layer Bit depth, z_n-1Layer bit depth for (n-1)th layer in m layer.

In step 103, set up interval velocity V with regard to m layer_nFunctional, wherein, V_nFor n-th in m layer The interval velocity of layer, calculates interval velocity V that functional is corresponding m layer during minimum_n, by interval velocity V of calculated m layer_n Interval velocity as m layer after updatingWherein,Interval velocity for the n-th layer in m layer after updating.Here, The minimum of functional can be calculated using various existing methods, for example, calculate the minimum of functional using quasi-Newton method.

For example, functional can be data item fitting expression, trend term fitting expression and smooth item fitting expression With.

For example, can be according to the interval velocity of m layer before updatingInterval velocity V with m layer_n, obtain data item matching table Reach formula.For example, data item fitting expression can be,

Formula（3）In, B represents data item fitting expression, Δ t_nBetween the time for the n-th layer in m layer and (n-1)th layer Every Δ t_n=t_n-t_n-1,For the weight coefficient of the data item of the n-th layer in m layer, V_n-1Layer speed for (n-1)th layer in m layer Degree.

For example, can be according to interval velocity V of m layer_nAnd trend function, obtain trend term fitting expression.For example, trend letter Number calculation expression can be,

Formula（4）In, V^trendT () represents trend function, V_aFor the instantaneous velocity on ground top layer, V_∞Wink for infinite deep layer Shi Sudu, Δ V are the excursion of instantaneous velocity, k_aFor previously given control parameter, t is the time.

For example, trend term fitting expression can be,

Formula（5）In, C represents trend term fitting expression,For the weight coefficient of the trend term of the n-th layer in m layer,Interval velocity V for (n-1)th layer in m layer_n-11- (τ/Δ t_n) power,For in m layer n-th layer Interval velocity V_nτ/Δ t_nPower, V^trend(t_n-1+ τ) it is time t=t_n-1Trend function during+τ.

For example, choose smoothing factor to m layer interval velocity V_nIt is smoothed, obtain smooth item matching expression Formula.For example, smooth item fitting expression is,

Formula（6）In, D represents smooth item fitting expression,For unit characteristic number,For the n-th layer in m layer Smoothing factor, Δ t_n+1For (n+1)th layer of time interval with n-th layer in m layer, Δ t_n+1=t_n+1-t_n, t_n+1For in m layer (n+1)th layer of time, V_n+1Interval velocity for (n+1)th layer in m layer.

The weight coefficient of the data item of the n-th layer in m layerThe weight coefficient of the trend term of the n-th layer in m layerAnd m The smoothing factor of the n-th layer in individual layerValue can artificially be set（For example, ）, only need to meet?.

At step 104, the interval velocity to m layer after updatingBe averaging, m layer after being updated average Interval velocityWherein,Average interval velocity for the n-th layer in m layer after updating.

For example, calculate the average interval velocity of the n-th layer in m layer after updatingFormula as follows,

Formula（7）In,For update after m layer in n-th layer average interval velocity,For m after updating The interval velocity of i-th layer in layer.

In step 105, the average interval velocity according to m layer before updatingAverage layer with m layer after renewal SpeedCalculate remaining curvature γ of m layer after updating_n, wherein, γ_nSurplus for the n-th layer in m layer after updating Remaining curvature.

For example, calculate remaining curvature γ of the n-th layer in m layer after updating_nFormula be,

In step 106, using remaining curvature γ of m layer after updating_nInterval velocity to m layer before updating It is corrected.

Specifically, remaining curvature γ of m layer after being updated according to method of the present invention_n, typically recognize It is the interval velocity of m layer after the renewal being obtained using method of the present inventionFor the interval velocity of accurate m layer, count Remaining curvature γ of m layer after the renewal obtaining_nAverage interval velocity for m layer before updatingWith the m after renewal The average interval velocity of individual layerRatio, therefore can be utilized this ratio to update before m layer interval velocityCarry out school Just, specifically, by the interval velocity of m layer before updatingIt is multiplied by the remaining curvature of m layer after respective renewal respectively γ_nInverse, the interval velocity V ' of m layer after being corrected_n.For example, calculate the interval velocity of the n-th layer in m layer after correction V′_nFormula as follows：

Through formula（9）The interval velocity V ' of the m layer obtaining after correction_nMore stable reliability, it is to avoid oscillatory occurences.For example, As γ 5=0.5, after correction the 5th layer of interval velocity

According to the interval velocity of m layer after the renewal that method of the present invention obtains, can be with m layer before updating Interval velocity keeps less deviation, the value of functional can be made less, such interval velocity is more reliable and more stable again.

After the interval velocity of m layer before updating being corrected using remaining curvature using method of the present invention, right Answer the layer bit depth on time point also can be adjusted, for example, due to the time of interval velocity and this layer that layer bit depth is this layer Product, therefore, after interval velocity changes, corresponding layer bit depth also can change, can according to correction after m layer interval velocity and The product of the time of m layer corrected after m layer layer bit depth, m layer after remaining curvature correction layer speed The layer bit depth of degree and m layer is more accurate, is conducive to the judgement to subsurface geologic structures and the prediction to oil-gas Layer.

Method of the present invention obtains reliable and stable instantaneous velocity based on the root mean sequare velocity of pickup, by belt restraining Optimal way realize stable remaining curvature speed and update.

Although be particularly shown and described the present invention, those skilled in the art with reference to its exemplary embodiment It should be understood that in the case of the spirit and scope of the present invention being limited without departing from claim, can be so that form be carried out to it With the various changes in details.

Claims (11)

1. a kind of method interval velocity being corrected using remaining curvature, methods described includes：

A () extracts the root mean sequare velocity of m layer from vertical speed functionWherein,Mean square for the n-th layer in m layer Root speed, n ∈ [1, m],

Root mean sequare velocity according to the m layer extractingThe interval velocity of m layer before being updatedWherein,For updating The interval velocity of the n-th layer in m front layer；

(b) interval velocity to m layer before updatingIt is averaging, the average interval velocity of m layer before being updatedIts In,Average interval velocity for the n-th layer in m layer before updating；

C () sets up interval velocity V with regard to m layer_nFunctional, wherein, V_nFor the interval velocity of the n-th layer in m layer, count Calculate interval velocity V that functional is corresponding m layer during minimum_n, by interval velocity V of calculated m layer_nAs the m after updating The interval velocity of individual layerWherein,Interval velocity for the n-th layer in m layer after updating；

(d) interval velocity to m layer after updatingIt is averaging, the average interval velocity of m layer after being updatedIts In,Average interval velocity for the n-th layer in m layer after updating；

E () is according to the average interval velocity of m layer before updatingAverage interval velocity with m layer after renewalCalculate more Remaining curvature γ of m layer after new_n, wherein, γ_nRemaining curvature for the n-th layer in m layer after updating；

F () is using remaining curvature γ of m layer after updating_nInterval velocity to m layer before updatingIt is corrected,

Wherein, calculate the average interval velocity of the n-th layer in m layer before updating in step (b)Formula as follows,

$\stackrel{\‾}{V_n^{old}}=\frac{z_n}{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\frac{z_n-z_{n-1}}{V_i^{old}}},$

Wherein, V_i ^oldFor the interval velocity of i-th layer in n layer before updating, z_nFor the layer bit depth of the n-th layer in m layer, z_n-1 Layer bit depth for (n-1)th layer in m layer.

2. method according to claim 1, wherein, calculates the layer speed of the n-th layer in m layer before updating in step (a) DegreeFormula as follows,

$V_n^{old}=\sqrt{\frac{{\tilde{V}}_n^2{t}_n-{\tilde{V}}_{n-1}^2{t}_{n-1}}{t_n-t_{n-1}}},$

Wherein,For the root mean sequare velocity of (n-1)th layer in m layer, t_nFor the time of the n-th layer in m layer, t_n-1For m layer In (n-1)th layer of time.

3. method according to claim 1, wherein, described functional is data item fitting expression, trend term matching table Reach formula and the sum of smooth item fitting expression.

4. method according to claim 3, wherein, according to the interval velocity of m layer before updatingLayer speed with m layer Degree V_n, obtain data item fitting expression.

5. method according to claim 4, wherein, data item fitting expression is,

$B=\frac{1}{2}\underset{n=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{\Δt}}_n\·w_n^B{\[\sqrt{\frac{V_n^2-V_{n-1}^2}{2ln(V_n/V_{n-1})}}-V_n^{old}\]}^2,$

Wherein, B represents data item fitting expression, Δ t_nFor the time interval of the n-th layer in m layer and (n-1)th layer, Δ t_n= t_n-t_n-1, t_nFor the time of the n-th layer in m layer, t_n-1For the time of (n-1)th layer in m layer,For n-th in m layer The weight coefficient of the data item of layer, V_n-1Interval velocity for (n-1)th layer in m layer.

6. method according to claim 3, wherein, according to interval velocity V of m layer_nAnd trend function, obtain trend term and intend Close expression formula.

7. method according to claim 6, wherein, the calculation expression of trend function is,

$V^{trend}\left(t\right)=\frac{V_a\·V_{\mathrm{\∞}}}{V_a+\mathrm{\Δ}V\·\exp (-k_{a}t\·V_{\mathrm{\∞}}/\mathrm{\Δ}V)},$

Wherein, V^trendT () represents trend function, V_aFor the instantaneous velocity on ground top layer, V_∞For the instantaneous velocity of infinite deep layer, Δ V is the excursion of instantaneous velocity, k_aFor previously given control parameter, t is the time.

8. method according to claim 7, wherein, trend term fitting expression is,

$C=\frac{1}{2}\underset{n=1}{\overset{m}{\mathrm{\Σ}}}\underset{0}{\overset{{\mathrm{\Δt}}_n}{\∫}}{w}_n^C{\[V_{n-1}^{1-(\mathrm{\τ}/{\mathrm{\Δt}}_n)}\·V_n^{\mathrm{\τ}/{\mathrm{\Δt}}_n}-V^{trend}(t_{n-1}+\mathrm{\τ})\]}^{2}d\mathrm{\τ},$

Wherein, C represents trend term fitting expression, Δ t_nFor the time interval of the n-th layer in m layer and (n-1)th layer, Δ t_n= t_n-t_n-1, t_nFor the time of the n-th layer in m layer, t_n-1For the time of (n-1)th layer in m layer,For n-th in m layer The weight coefficient of the trend term of layer,Interval velocity V for (n-1)th layer in m layer_n-11- (τ/Δ t_n) power, For in m layer n-th layer interval velocity V_nτ/Δ t_nPower, V^trend(t_n-1+ τ) it is time t=t_n-1Trend letter during+τ Number.

9. method according to claim 3, wherein, chooses interval velocity V to m layer for the smoothing factor_nIt is smoothed, Obtain smooth item fitting expression.

10. method according to claim 9, wherein, smooth item fitting expression is,

$D=\frac{\stackrel{\‾}{V^2\mathrm{\Δ}t}}{2}\underset{n=1}{\overset{m}{\mathrm{\Σ}}}{w}_n^D\·{\mathrm{\Δt}}_n\·{\mathrm{\Δt}}_{n+1}{\[\frac{ln(V_{n+1}/V_n)}{{\mathrm{\Δt}}_{n+1}}\·\frac{ln(V_n/V_{n-1})}{{\mathrm{\Δt}}_n}\]}^2,$

Wherein, D represents smooth item fitting expression,For unit characteristic number,For the smoothing factor of the n-th layer in m layer, Δt_nFor the time interval of the n-th layer in m layer and (n-1)th layer, Δ t_n=t_n-t_n-1, Δ t_n+1For (n+1)th layer in m layer with The time interval of n-th layer, Δ t_n+1=t_n+1-t_n, t_nFor the time of the n-th layer in m layer, t_n-1For (n-1)th layer in m layer Time, t_n+1For the time of (n+1)th layer in m layer, V_nFor the interval velocity of the n-th layer in m layer, V_n+1For n-th in m layer + 1 layer of interval velocity, V_n-1Interval velocity for (n-1)th layer in m layer.

11. methods according to claim 1, wherein, calculate remaining curvature γ of the n-th layer in m layer after updating_n's Formula is,

${\mathrm{\γ}}_n=\frac{\stackrel{\‾}{V_n^{old}}}{\stackrel{\‾}{V_n^{new}}}.$