CN102359924A - Detection method for coal petrography intensity based on multi-wave seismic data - Google Patents

Abstract

The invention relates to a detection method for the coal petrography intensity based on multi-wave seismic data, which comprises the following steps that: A, vertical and transverse wave speed models and density models are obtained through multi-wave seismic data and logging data, and initial speed models are built through logging speed models; B, synthetic seismic records are generated, and the total residual error of overlapped data and the synthetic seismic records is obtained through calculation; C, the total residual error of a wave impedance model and a logging external push wave impedance model is obtained through calculation; D, the objective function value is calculated, the vertical and transverse wave speed of each layer is modified when the value is judged not to meet the precision requirement, a new vertical and transverse wave speed model is built, the operation returns to the step A, and the continuous iteration is carried out until the objective function value convergence; and E, after the objective function value convergence, the vertical and transverse wave speed data reaching the logging resolution and the density data obtained through calculation are obtained, slices along a coal bed are extracted, and the firmness factor of the objective coal bed on the whole plane can be obtained through calculation. The problem of judgment of coal and gas projection possibility in the coal bed is solved.

Description

A kind of detection method of the coal petrography intensity based on the multi-wave seismic data

Technical field

The present invention relates to the detection range in colliery, relate in particular to a kind of detection method of the coal petrography intensity based on the multi-wave seismic data.

Background technology

Coal and gas are outstanding to be a kind of extremely complicated mine gas dynamic phenomenon that runs in the Coal Production, and its mechanism still is not familiar with by people up to now fully.A large amount of mine field datas and results of laboratory show that the outstanding of coal and gas is the result of various factor comprehensive action such as structure of terrestrial stress, coal petrography intensity, cranny development, coal; Wherein the intensity level of coal petrography and certain mode of texturing (uniaxial compression, stretching, shearing) interrelate, and have reflected the survivability of coal petrography, are one of outstanding important parameters of forecasting coal and gas.

Several kinds of modes below the current existence are judged coal petrography intensity: to U.S.'s type area's coal logging and borehole data, through interval transit time and coal petrography STATISTICAL ANALYSIS OF STRENGTH, set up method and the experimental formula of utilizing SVEL prediction coal petrography intensity.Set up the method for utilizing velocity of longitudinal wave prediction compressive strength through indoor SVEL test and the test of coal petrography uniaxial compressive strength, and be applied to the on-the-spot coal petrography prediction of strength of mining design and down-hole.The compressive strength that has proved the coal containing methane gas rock through numerical simulation experiment is along with the increase of gas pressure is non-linear reduction.Through load test stabilization, tested the wetness degree of coal petrography and the relation between the compressive strength, along with the increase of WS, the compressive strength of coal petrography reduces.Measure the error that exists in view of the frangibility and the compressive strength of coal petrography, can utilize reconstruct coal sample compressive strength to approach the method for former coal sample.Because the measurement more complicated of coal petrography intensity; The intensive parameter of measuring under the single mode of texturing is difficult to reflect the survivability of coal petrography comprehensively; And soundness reflection is the ability of the opposing destruction of rock under the compound action of several kinds of modes of texturing, so generally adopt solid coefficient f to estimate the intensity of coal petrography at home.Usually coal seam solid coefficient f is given prominence to one of detailed rules and regulations single index as coal and gas, and stipulate that its critical value is 0.5, when f＞0.5, coal petrography intensity is higher, and it is dangerous less that coal and gas generation are given prominence to; When f＜0.5, coal and gas take place outstanding dangerous higher, but whether be bound to take place outstanding, also necessary other various factors of analysis-by-synthesis.So, can a favourable evaluate parameter be provided for Safety of Coal Mine Production if can before starting building in new exploiting field, carry out three-dimensional prediction to the coal petrography soundness.

At present, the general method that adopts drill hole sampling to measure of coal petrography soundness prediction is carried out in the colliery.Though this method can directly obtain the strength information of coal body, the quantity of information of single-point is not enough to be used on whole work area, carrying out the outburst prediction of coal and gas; The Changing Pattern that obtains regional upward coal petrography soundness is most important for the safety in production in colliery.Through the dissimilar projecting coal bed coal samples in the whole nation have been carried out laboratory measurement; Drawn the solid coefficient of coal petrography and the general rule between the coal rock deformation modulus, this also provides the rock physics mechanical foundation for the intensity of utilizing seismic exploration technique prediction coal petrography.Deformation modulus and modulus in compression all are the constrictive important indicators of reflection rock, and lateral confinement condition suffered when both difference are the uniaxial compression test is different, but both can set up linear conversion relation through Poisson ratio.The Poisson ratio of rock and modulus in compression can obtain with vertical, shear wave velocity and density conversion; And in three-dimensional three-component (3D3C) seismic prospecting; Inverting through the multi-wave seismic data can obtain vertical, the shear wave velocity and the density parameter of rock in the whole work area, and this makes becomes possibility through coal petrography solid coefficient in the whole work area of multi-wave seismic data inversion.

Current needs are a kind of to detect coal petrography intensity according to multi-wave seismic and log data, and then judges the technical scheme of the possibility that coal and gas in the target coal seam are outstanding, the safety in production in guarantee colliery.

Summary of the invention

Technical matters to be solved by this invention provides a kind of detection method of the coal petrography intensity based on the multi-wave seismic data, to solve the problem of the possibility of judging that coal and gas are given prominence in the target coal seam, has ensured the safety in production in colliery.

In order to address the above problem, the invention provides a kind of detection method of the coal petrography intensity based on the multi-wave seismic data, comprising:

Steps A, obtain vertical, shear wave velocity model and density model through multi-wave seismic data and log data, and through logging speed modelling initial velocity model;

Step B, generate the theogram of PP ripple and PS ripple respectively, calculate total residual error of superposition of data and theogram according to initial velocity model;

Step C, vertical, shear wave impedance through said initial velocity model and the density calculation initial model that calculates according to vertical, shear wave velocity model that obtains and density model, calculate total residual error of surge impedance model and well logging extrapolation surge impedance model;

Step D, said superposition of data and the said surge impedance model of total residual sum of theogram and total residual error of well logging extrapolation surge impedance model that basis obtains are calculated the target function value that PP ripple and PS ripple well shake joint inversion; Judge if target function value does not satisfy accuracy requirement, then revise vertical, the shear wave velocity value of each layer, set up new vertical, shear wave velocity model, and turn back to said steps A, continue till the convergence of iteration to target function value;

Step e, after the convergence of said target function value, obtain one and reach vertical, the shear wave velocity data volume of well logging resolution and the density data body that calculates, extract section along the coal seam, calculate the solid coefficient that obtains the target coal seam on the whole plane

Further, said method also can comprise: also comprise in the said steps A: PS ripple superposition of data is compressed to longitudinal wave reflection on the time, realizes the coupling fully of layer position; Through the wavelet modulation, the form of the PS rolling land shake wavelet after PP ripple and the compression is identical, obtain the multi-wave seismic data.

Further, said method also can comprise: said step through logging speed modelling initial velocity model comprises: after layer adds a small amount of disturbance with the logging speed model, set up initial velocity model;

Wherein, judge, then after the velocity of longitudinal wave curve calculates, set up initial velocity model through Castagna mode and Gardner mode respectively if the work area of target coal seam does not have shear wave and density logging curve.

Further, said method also can comprise: also comprise among the said step B: calculate PP ripple and PS wave reflection coefficient under the average incident angle according to initial velocity model through following formula, generate the theogram of PP ripple and PS ripple respectively

With

Through the amplitude magnitude adjustment PP ripple of composite traces and the amplitude magnitude of PS wave datum body, make that the PS wave amplitude after PP ripple and the compression has comparability; Calculate total residual error S of superposition of data and composite traces _Raw-S _Syn

Wherein, formula is:

$\left\{\begin{array}{c}{r}_{\mathrm{pp}}\left(\mathrm{\&alpha;}\right)\&ap;a\frac{\mathrm{\&Delta;}{v}_p}{v_p}+b\frac{\mathrm{\&Delta;}{v}_s}{v_s}\\ r_{\mathrm{ps}}\left(\mathrm{\&alpha;}\right)\&ap;c\frac{\mathrm{\&Delta;}{v}_p}{v_p}+d\frac{\mathrm{\&Delta;}{v}_s}{v_s}\\ a=\frac{1}{8}(1-4{\mathrm{\&gamma;}}^2{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000092299420000011.png,HDA0000092299420000021.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\mathrm{\&alpha;}+\frac{4}{{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA0000092299420000011.png,HDA0000092299420000021.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&alpha;}})\\ b=-4{\mathrm{\&gamma;}}^2{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000092299420000011.png,HDA0000092299420000021.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\mathrm{\&alpha;}\\ c=-\frac{\tan \mathrm{\&beta;}}{8\mathrm{\&gamma;}}(1-2{\mathrm{\&gamma;}}^2{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000092299420000011.png,HDA0000092299420000021.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\mathrm{\&alpha;}+2\mathrm{\&gamma;}\cos \mathrm{\&alpha;}\cos \mathrm{\&beta;})\\ d=\frac{\tan \mathrm{\&beta;}}{2\mathrm{\&gamma;}}({4\mathrm{\&gamma;}}^2{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000092299420000011.png,HDA0000092299420000021.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\mathrm{\&alpha;}-4\mathrm{\&gamma;}\cos \mathrm{\&alpha;}\cos \mathrm{\&beta;})\end{array}\right.,$

Wherein, Δ v _p, Δ v _sVertical, the shear wave velocity difference of expression between two-layer up and down respectively, v _p, v _sThe average of vertical, the shear wave velocity of expression between two-layer up and down respectively, vertical, shear wave velocity is than γ=v _s/ v _pα representes the average of incident compressional angle and angle of transmission, and β representes the average of transverse wave reflection angle and angle of transmission; S _Raw-S _SynBe PP ripple stack seismic trace

Obtain synthetic seismic trace with inverting Between residual error and PS ripple stack seismic trace Obtain synthetic seismic trace with inverting

Between residual error with.

Further, said method also can comprise: also comprise among the said step C: vertical, the shear wave impedance of the density calculation initial model that calculates through initial velocity model and Gardner mode

With

Vertical, shear wave velocity model that extrapolation of the log data is obtained multiply each other with density model respectively and obtain

With

And total Residual Z of calculating the inverting surge impedance model that obtains and the extrapolation surge impedance model of logging well _Well-Z _Inv

Wherein, Z _Well-Z _InvThe P wave impedance that the data of extrapolating for logging well obtain

Obtain the P wave impedance with inverting

Between the S wave impedance that obtains of residual error and well logging extrapolation data

Obtain the S wave impedance with inverting Between residual error with.

Further, said method also can comprise: said step D is the objective function T that calculates PP ripple and PS ripple well shake joint inversion through following formula;

Wherein, formula is:

$\left\{\begin{array}{c}T={\mathrm{\&lambda;}}_1\&CenterDot;(S_{\mathrm{raw}}-S_{\mathrm{syn}})+{\mathrm{\&lambda;}}_2\&CenterDot;(Z_{\mathrm{well}}-Z_{\mathrm{inv}})\\ {\mathrm{\&lambda;}}_1+{\mathrm{\&lambda;}}_2=1\\ S_{\mathrm{raw}}-S_{\mathrm{syn}}=(S_{\mathrm{raw}}^{\left(\mathrm{pp}\right)}-S_{\mathrm{syn}}^{\left(\mathrm{pp}\right)})+(S_{\mathrm{raw}}^{\left(\mathrm{ps}\right)}-S_{\mathrm{syn}}^{\left(\mathrm{ps}\right)})\\ Z_{\mathrm{well}}-Z_{\mathrm{inv}}=(Z_{\mathrm{well}}^{\left(p\right)}-Z_{\mathrm{inv}}^{\left(p\right)})+(Z_{\mathrm{well}}^{\left(s\right)}-Z_{\mathrm{inv}}^{\left(s\right)})\end{array}\right.,$

Wherein, weights λ ₁, λ ₂The weight of seismic trace and logging module effect of contraction in the corresponding inverting of difference.

Further; Said method also can comprise: also comprise in the said step e: after said target function value convergence; Obtain one and reach vertical, the shear wave velocity data volume of well logging resolution and the density data body that calculates through the Gardner mode; Extraction is along the section in coal seam, and obtains the solid coefficient f of the target coal seam on the whole plane through following formula

Wherein, formula is:

$f=\exp ((\mathrm{\&rho;}(v_p^2-2v_s^2)\&CenterDot;(1-\frac{{2\mathrm{\&sigma;}}^2}{1-\mathrm{\&sigma;}})-530.88)/207.19),$

Wherein, ρ is a density, and σ is a Poisson ratio, σ and vertical, shear wave velocity v _pWith v _sBetween relation following:

$\mathrm{\&sigma;}=\frac{0.5{(v_p/v_s)}^2-1}{{(v_p/v_s)}^2-1}.$

Compared with prior art, use the present invention, judge the soundness of coal petrography through the joint inversion quantification of multi-wave seismic and log data, and then the possibility that coal and gas are given prominence in the decidable target coal seam, the safety in production in colliery ensured.

Description of drawings

Fig. 1 is vertical a, shear wave velocity of the present invention than the change curve that is 1.5,2.0,3.0 o'clock Coefficient m, n;

Fig. 2 is the process flow diagram of the detection method of the coal petrography intensity based on the multi-wave seismic data of the present invention;

Fig. 3 is the modulus in compression planimetric map in 11-2 coal seam in the instance of the present invention;

Fig. 4 is the solid coefficient planimetric map in 11-2 coal seam in the instance of the present invention.

Embodiment

The present invention mainly is based on the soundness, deformation modulus of coal petrography and the rock mechanics rule between vertical, the shear wave velocity, proposes to predict with the joint inversion quantification of multi-wave seismic and log data the soundness of coal petrography.According to the characteristics that the three-dimensional 3-component earthquake in coalfield is gathered, set up the well constrained inversion flow process of PP ripple and the equal incident angle partial stack of PS popin road collection; Utilize the solid coefficient and the conversion relation between the deformation modulus of coal petrography that the solid coefficient spatial variations rule of target coal seam is predicted, and coal and the outstanding zone of gas possibly take place in division.Result of practical application shows that this method can provide favourable evaluating for the safety in production in colliery.

It should be noted that: method of the present invention will be in concrete the realization through system between each equipment information interaction carry out the collection of information and/or data; And (can be that CPU etc. carries out control and treatment information and/or data through the controller in it; The present invention does not do any qualification to this); Can also carry out the storage and the transmission of information and/or data through various storeies (can be internal memory, hard disk or other memory devices) therebetween, the present invention does not do any qualification to this.

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

In order to explain method of the present invention, take a sample the relation of the solid coefficient that obtains the target coal petrography and vertical, shear wave velocity and density to the coal sample of target coal seam.

Obtaining the solid coefficient of coal petrography and the relation of mechanics parameter need take a sample to projecting coal bed, and projecting coal bed coal sample powdered basically, the difficulty that this just causes soundness to be measured.Through to a large amount of projecting coal bed samplings; Coal dust is pressed into the moulding coal sample of different soundnesses; And single shaft resistance to compression measurement result carried out regretional analysis, draw coal petrography solid coefficient f (dimensionless) and deformation modulus E (unit: the relation Mpa) satisfies:

E＝530.88+207.19ln(f)， (1)

Can be known by following formula: the soundness of coal petrography can strengthen along with the increase of modulus in compression, and the outstanding possibility of coal and gas reduces; Otherwise then the outstanding danger of coal and gas strengthens.Because it is the most representative projecting coal bed that the experiment coal sample is taken from collieries such as Huainan, Lu Ling respectively, can represent dissimilar projecting coal bed in the whole nation, so that this formula goes for is general projecting coal bed; And non-projecting coal bed for hard coal etc., the applicability of this formula then needs verify through further experiment.

The deformation modulus E and the relation between the modulus in compression λ of rock are following:

$E=(1-\frac{{2\mathrm{\&sigma;}}^2}{1-\mathrm{\&sigma;}})\mathrm{\&lambda;},---\left(2\right)$

Wherein, σ is a Poisson ratio, itself and vertical, shear wave velocity v _pWith v _sBetween relation following:

$\mathrm{\&sigma;}=\frac{0.5{(v_p/v_s)}^2-1}{{(v_p/v_s)}^2-1},---\left(3\right)$

Modulus in compression can pass through v _p, v _sAnd density p converts, and relational expression is following:

$\mathrm{\&lambda;}=\mathrm{\&rho;}(v_p^2-2v_s^2),---\left(4\right)$

Composite type (1-4), the reduction formula that can obtain the coal petrography solid coefficient is:

$f=\exp ((\mathrm{\&rho;}(v_p^2-2v_s^2)\&CenterDot;(1-\frac{{2\mathrm{\&sigma;}}^2}{1-\mathrm{\&sigma;}})-530.88)/207.19),---\left(5\right)$

Vertical, the shear wave velocity and the density parameter in solid coefficient and coal seam that can find out coal petrography from following formula is closely related, and these elastic parameters then can obtain through the inverting of multi-wave seismic data.Because the coal seam is a thin layer; Utilize geological data to be difficult to obtain the elastic parameter of thin layer separately; Need improve the resolution of multi-wave seismic data inversion through the constraint of log data, so the joint inversion of multi-wave seismic and log data is the key link of coal petrography soundness prediction.

Further specify the principle that multi-wave seismic and log data joint inversion obtain the solid coefficient of target coal seam below.

Send from focus, partway, still be called the PP ripple after once with what the compressional wave form propagated into measurement point at earth surface reflection with longitudinal wave propagation.Send from focus, partway, behind earth surface reflection, be called the PS ripple with what the shear wave form propagated into measurement point with longitudinal wave propagation.

Different with exploration of oil and gas field, multiwave multicomponent earthquake exploration in coalfield is owing to receive the restriction of aspects such as fund, acquisition condition, and three-dimensional three-component (3D3C) earthquake-capturing is often arranged weak point, the position angle is narrow, degree of covering is less; The interval prestack inversion technology of angles of azimuth commonly used in the data inversion of oil gas field multi-wave seismic is used for coalfield multi-wave seismic data deficiency current conditions.Can be under average incident angle hypothesis from many ripples partial stack data inversion elastic parameter of average incident angle, this also provides thinking for the inverting of coalfield multi-wave seismic data.At first, the average incident angle of many ripples partial stack data is carried out match.In many ripples AVO (amplitude is with the variation of offset distance) inverting, the Gardner algorithm often is used to characterize between sedimentogeneous rock density and the velocity of longitudinal wave and concerns, the relation that has drawn on this basis between P ripple, S wave reflection coefficient and the speed is:

$\left\{\begin{array}{c}{r}_{\mathrm{pp}}\left(\mathrm{\&alpha;}\right)\&ap;a\frac{\mathrm{\&Delta;}{v}_p}{v_p}+b\frac{\mathrm{\&Delta;}{v}_s}{v_s}\\ r_{\mathrm{ps}}\left(\mathrm{\&alpha;}\right)\&ap;c\frac{\mathrm{\&Delta;}{v}_p}{v_p}+d\frac{\mathrm{\&Delta;}{v}_s}{v_s}\\ a=\frac{1}{8}(1-4{\mathrm{\&gamma;}}^2{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000092299420000011.png,HDA0000092299420000021.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\mathrm{\&alpha;}+\frac{4}{{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA0000092299420000011.png,HDA0000092299420000021.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&alpha;}})\\ b=-4{\mathrm{\&gamma;}}^2{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000092299420000011.png,HDA0000092299420000021.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\mathrm{\&alpha;}\\ c=-\frac{\tan \mathrm{\&beta;}}{8\mathrm{\&gamma;}}(1-2{\mathrm{\&gamma;}}^2{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000092299420000011.png,HDA0000092299420000021.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\mathrm{\&alpha;}+2\mathrm{\&gamma;}\cos \mathrm{\&alpha;}\cos \mathrm{\&beta;})\\ d=\frac{\tan \mathrm{\&beta;}}{2\mathrm{\&gamma;}}({4\mathrm{\&gamma;}}^2{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000092299420000011.png,HDA0000092299420000021.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\mathrm{\&alpha;}-4\mathrm{\&gamma;}\cos \mathrm{\&alpha;}\cos \mathrm{\&beta;})\end{array}\right.,---\left(6\right)$

In the formula (6), Δ v _p, Δ v _sVertical, the shear wave velocity difference of expression between two-layer up and down respectively, v _p, v _sThe average of vertical, the shear wave velocity of expression between two-layer up and down respectively, vertical, shear wave velocity is than γ=v _s/ v _pα representes the average of incident compressional angle and angle of transmission, and β representes the average of transverse wave reflection angle and angle of transmission.Draw through the inversion error analysis: even the compressional wave or the shear wave velocity difference on stratum reach 40% up and down at the interface; Carry out the AVO joint inversion with formula (6) and also can inversion error be controlled in 10%, so the AVO inverting of carrying out the coal seam with formula (6) can reach accuracy requirement.

Because dv _s=γ dv _pSo, can set up following approximation relation:

$\frac{\mathrm{\&Delta;}{v}_p}{v_p}\&ap;\frac{\mathrm{\&Delta;}{v}_s}{v_s},---\left(7\right)$

Therefore formula (6) can further be approximately:

$\left\{\begin{array}{c}{r}_{\mathrm{pp}}\left(\mathrm{\&alpha;}\right)\&ap;m\frac{\mathrm{\&Delta;}{v}_p}{v_p}\\ r_{\mathrm{ps}}\left(\mathrm{\&alpha;}\right)\&ap;n\frac{\mathrm{\&Delta;}{v}_s}{v_s}\\ m=\frac{1}{8}(1-36{\mathrm{\&gamma;}}^2{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000092299420000011.png,HDA0000092299420000021.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\mathrm{\&alpha;}+\frac{4}{{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA0000092299420000011.png,HDA0000092299420000021.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&alpha;}})\\ n=-\frac{1}{8}\frac{\tan \mathrm{\&beta;}}{\mathrm{\&gamma;}}(1-18{\mathrm{\&gamma;}}^2{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000092299420000011.png,HDA0000092299420000021.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\mathrm{\&alpha;}+18\mathrm{\&gamma;}\cos \mathrm{\&alpha;}\cos \mathrm{\&beta;})\end{array}\right.,---\left(8\right)$

Formula (8) has provided the approximation relation between PP ripple, PS wave reflection coefficient and the speed, and visible Coefficient m, n have determined the Changing Pattern of PP ripple and PS wave reflection coefficient.

Can be converted by angle [alpha] and γ with the Snell theorem owing to angle beta from formula (8), the value of Coefficient m, n is determined than γ by angle [alpha] and vertical, shear wave velocity.At vertical, shear wave velocity ratio is 1.5,2.0,3.0 o'clock; Obtain Coefficient m shown in Figure 1, n change curve; It is thus clear that for the PP wave datum, near the nearly zero-offset and incident angle less than a segment limit of 500 within, Coefficient m changes mild; M value during basically around zero incident angle changes, and has reflected that PP wave reflection index variation is less; In this segment limit, PP wave propagation distance is short, and the stratum is little to the attenuation by absorption effect of energy, and frequency band is the wideest, and reflected energy is strong and the nmo stretching distortion is minimum, is the topmost energy ingredient of superposition of data.Though increase comparatively fast greater than 500 o'clock PP wave reflection coefficients in incident angle, the distortion of the nmo stretching of this moment can be bigger, the energy absorption decling phase generally can excise the energy of this part to seriously when data processing; So it is more reasonable that the PP ripple selects nearly zero-offset partial stack data to carry out inverting.For the PS wave datum, reflection coefficient is less during nearly zero-offset, but is near 300 in incident angle, and especially in 200～400 intervals, the absolute value of n value is bigger, reflects the bigger reflection coefficient of PS ripple.The energy that the PS wave datum of this fragment position is participated in stack is the strongest; Take into account the attenuation by absorption on nmo stretching distortion and stratum, the PS ripple selects the medium offset distance partial stack data of average incident angle 300 relatively to be applicable to the collection inverting of road, angle.Can find out that from the Changing Pattern of Fig. 1 Coefficient m, n curve variation vertical, the shear wave velocity ratio is less to the selection influence of average incident angle.Because vertical, shear wave velocity can be distinguished corresponding speed than minimum, moderate and very big three kinds of situation than value 1.5,2.0,3.0, has feasibility so under average incident angle hypothesis, carry out the inverting of multi-wave seismic data.

In order to obtain the lithological information of thin seam, the joint inversion of PP ripple and PS ripple need be carried out under the constraint of log data to improve the resolution of inverting.PP ripple and PS wavelength-division are not carried out inverting with the partial stack data of zero degree and the average incident angle of 30 degree, obtain vertical, shear wave velocity and density, and the objective function T of foundation is following:

$\left\{\begin{array}{c}T={\mathrm{\&lambda;}}_1\&CenterDot;(S_{\mathrm{raw}}-S_{\mathrm{syn}})+{\mathrm{\&lambda;}}_2\&CenterDot;(Z_{\mathrm{well}}-Z_{\mathrm{inv}})\\ {\mathrm{\&lambda;}}_1+{\mathrm{\&lambda;}}_2=1\\ S_{\mathrm{raw}}-S_{\mathrm{syn}}=(S_{\mathrm{raw}}^{\left(\mathrm{pp}\right)}-S_{\mathrm{syn}}^{\left(\mathrm{pp}\right)})+(S_{\mathrm{raw}}^{\left(\mathrm{ps}\right)}-S_{\mathrm{syn}}^{\left(\mathrm{ps}\right)})\\ Z_{\mathrm{well}}-Z_{\mathrm{inv}}=(Z_{\mathrm{well}}^{\left(p\right)}-Z_{\mathrm{inv}}^{\left(p\right)})+(Z_{\mathrm{well}}^{\left(s\right)}-Z_{\mathrm{inv}}^{\left(s\right)})\end{array}\right.,---\left(9\right)$

Wherein, S _Raw-S _SynBe PP ripple stack seismic trace

Obtain synthetic seismic trace with inverting

Between residual error and PS ripple stack seismic trace

Obtain synthetic seismic trace with inverting

Between residual error with; S when carrying out the independent inverting of PP ripple _Raw-S _SynThe residual error of having only the compressional wave part, but research shows: compare with utilizing compressional wave separately, consider simultaneously that in objective function the residual error of compressional wave and converted shear wave can increase substantially the precision of inverting.In the formula (9), Z _Well-Z _InvThe P wave impedance that the data of extrapolating for logging well obtain

Obtain the P wave impedance with inverting

Between the S wave impedance that obtains of residual error and well logging extrapolation data Obtain the S wave impedance with inverting

Between residual error with.Weights λ ₁, λ ₂The weight of seismic trace and logging module effect of contraction in the corresponding inverting of difference, λ ₁+ λ ₂=1, when respectively getting 50%, log data and the geological data constraint weight in refutation process respectively accounts for half the; Work as λ ₁Showed the complete constrained inversion result of geological data at=1 o'clock, log data does not play effect of contraction; Work as λ ₂=1 o'clock, show the complete constrained inversion result of log data, geological data does not play effect of contraction, is equivalent to logging module is extrapolated.If the reliability of a certain data is lower, weight that can corresponding its constraint of reduction.

As shown in Figure 2, the detection method of the coal petrography intensity based on the multi-wave seismic data of the present invention may further comprise the steps:

Step 210, system are compressed to longitudinal wave reflection on the time with PS ripple superposition of data, realize the coupling fully of layer position; Through the wavelet modulation, that the form of the PS rolling land shake wavelet after PP ripple and the compression is identical;

Step 220, system obtain high-resolution vertical, shear wave velocity and density model through log data, and along layer the logging speed model are added a small amount of disturbance (as ± 1%) extrapolation as initial velocity model;

Wherein, judge, then can convert from the velocity of longitudinal wave curve with Castagna formula and Gardner algorithm respectively if the work area of target coal seam does not have shear wave and density logging curve;

Step 230, system calculate PP ripple and PS wave reflection coefficient under the average incident angle according to initial velocity model with formula (6), make the theogram of PP ripple and PS ripple respectively

With Through the amplitude magnitude adjustment PP ripple of composite traces and the amplitude magnitude of PS wave datum body, make that the PS wave amplitude after PP ripple and the compression has comparability; Calculate total residual error S of superposition of data and composite traces _Raw-S _Syn

Wherein, S _Raw-S _StnBe PP ripple stack seismic trace

Obtain synthetic seismic trace with inverting

Between residual error and PS ripple stack seismic trace

Obtain synthetic seismic trace with inverting

Between residual error with.

Step 240, system are through initial velocity model and Gardner algorithm convert vertical, the shear wave impedance of the density calculation initial model that obtains

With Vertical, shear wave velocity model that extrapolation of the log data is obtained multiply each other with density model respectively and obtain

With

And total Residual Z of calculating the inverting surge impedance model that obtains and the extrapolation surge impedance model of logging well _Well-Z _Inv

The objective function T of PP ripple and PS ripple well shake joint inversion calculates in step 250, system through formula (9);

Step 260, system are judged if objective function T does not satisfy the precision prescribed requirement, then revise vertical, the shear wave velocity value of each layer, set up new vertical, shear wave velocity model, and return step 220, continue till the convergence of iteration to objective function T value;

Step 270, system are after said target function value convergence; Obtain one and reach vertical, the shear wave velocity data volume of well logging resolution and the density data body that converts and obtain through the Gardner algorithm; Extraction is calculated the solid coefficient that obtains the target coal seam on the whole plane along the section in coal seam.

When above-mentioned inversion step finishes; One be can obtain and vertical, the shear wave velocity data volume of well logging resolution and the density data body that obtains with the conversion of Gardner algorithm reached; Extraction is along the section in coal seam, and is updated to the solid coefficient that formula (5) just can obtain the coal seam on the whole plane.Some rock physics experimental datas show that the velocity of longitudinal wave of coal petrography and the Changing Pattern between the density still satisfy exponential relationship; And it is similar with the form of Gardner algorithm; But this also can cause finding the solution of follow-up coal petrography solid coefficient to have certain error, but the regional relative Changing Pattern of going up the coal petrography soundness can not change; The joint inversion of many wave datum simultaneously improves precision vertical, S-wave velocity inversion to a great extent, the error that is caused by the Gardner algorithm when this also can remedy the calculating of coal petrography solid coefficient to a certain extent.

Through instance the present invention is described further below.

For the feasibility of the inventive method flow process is described, test through the three-dimensional three-component seismic data of Gu Qiao colliery, Huainan block.The target coal seam of research is the 11-2 coal, and it is main with powder coal, fragment coal that boring discloses the coal body structure, is local area master mining coal seam.

PP ripple and PS rolling land shake data to the 3D3C earthquake-capturing have been carried out structure elucidation and well constrained inversion; (wherein 10m * 10m) can find out that the modulus in compression from major fault zone coal seam far away generally concentrates between the 400-900Mpa to obtain the modulus in compression planimetric map in 11-2 shown in Figure 3 coal seam; But in the bottle green indicating range near distributed fault, the modulus in compression of coal petrography is less than 200Mpa, intensity relatively a little less than.Fig. 4 is the convert solid coefficient planimetric map (10m * 10m) wherein in the 11-2 coal seam obtain of through type (3).The solid coefficient that can find out coal petrography in the work area between 0.2-0.6, shows that the intensity of coal petrography is generally not high mostly, has the outstanding possibility of coal and gas.On the east-west F87 distributed fault of Fig. 4 black arrow indication and the local location of F119 distributed fault because the tectonic denudation effect, the coal seam disappearance takes place but filling a large amount of sand shale chips lay equal stress on new glued, so the f value is higher.Near the both sides, north and south of major fault F87 distributed fault and near the east side of the major fault F119 distributed fault of arrow indication; Especially oval frame indicating positions; Owing to receive the effect of tectonic stress, coal petrography is broken, f value on a large scale occurs less than 0.1 zone; These zone very possible structure coals are comparatively grown, and it is dangerous higher that coal and gas generation are given prominence to.Two square frame indicating positions are because of having laid the tunnel in Fig. 4, and the coal seam lacks, and main medium is an air, so the f value is also lower.According to the feedback result of ore deposit side's downhole production, the coal seam is broken near F87 and F119 tomography, and the structure coal is relatively grown, and it is bigger that the outstanding possibility of coal and gas takes place, and predicts the outcome identical with this.

In sum, draw to draw a conclusion through this instance:

(1) there is correlationship between the deformation modulus of coal petrography and the solid coefficient; Utilize the average incident angle partial stack road collection of multi-wave seismic data to carry out inverting; Can obtain quantitative coal seam parameters such as wave impedance, speed, density in length and breadth simultaneously; And then be converted into the solid coefficient of reflection coal petrography intensity, for the safety in production in colliery provides favourable evaluating; And also being conventional longitudinal wave earthquake exploration engineering, this point is difficult to realize.

(2) multi-wave seismic data inversion result shows, higher from the modulus in compression and the solid coefficient of the major fault zone general coal petrography in zone far away, it is less that the outstanding possibility of coal and gas takes place; And near distributed fault, especially in the zone that some tectonic stresses are comparatively concentrated, the solid coefficient of coal petrography is less, and it is also big more that the outstanding possibility of coal and gas takes place; On some big distributed faults; Because the coal seam lacks because of tectonization; Again it is glued that compacting can take place sand shale chip stuff, thus the high high soundness that does not reflect coal petrography unusually of the subregional solid coefficient in big distributed fault top, but the high soundness of stuff.

(3) the coal petrography soundness Forecasting Methodology that proposes of this paper is that the decipher of coalfield multi-wave seismic data provides new thinking; But reach the outstanding exact evaluation of coal and gas; Single parameter is not enough; Also need from the multi-wave seismic data, separate and translate more formation parameter,, thereby provide safeguard for the safety in production in colliery like fracture development density, anisotropy, factor of porosity, permeability etc.

The above; Be merely the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, anyly is familiar with this technological people in the technical scope that the present invention disclosed; The variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection domain of claim.

Claims (7)

1. the detection method based on the coal petrography intensity of multi-wave seismic data is characterized in that, comprising:

Steps A, obtain vertical, shear wave velocity model and density model through multi-wave seismic data and log data, and through logging speed modelling initial velocity model;

Step B, generate the theogram of PP ripple and PS ripple respectively, calculate total residual error of superposition of data and theogram according to initial velocity model;

Step C, vertical, shear wave impedance through said initial velocity model and the density calculation initial model that calculates according to vertical, shear wave velocity model that obtains and density model, calculate total residual error of surge impedance model and well logging extrapolation surge impedance model;

Step D, said superposition of data and the said surge impedance model of total residual sum of theogram and total residual error of well logging extrapolation surge impedance model that basis obtains are calculated the target function value that PP ripple and PS ripple well shake joint inversion; Judge if target function value does not satisfy accuracy requirement, then revise vertical, the shear wave velocity value of each layer, set up new vertical, shear wave velocity model, and turn back to said steps A, continue till the convergence of iteration to target function value;

Step e, after the convergence of said target function value, obtain one and reach vertical, the shear wave velocity data volume of well logging resolution and the density data body that calculates, extract section along the coal seam, calculate the solid coefficient that obtains the target coal seam on the whole plane.

2. the method for claim 1 is characterized in that,

Also comprise in the said steps A: PS ripple superposition of data is compressed to longitudinal wave reflection on the time, realizes the coupling fully of layer position; Through the wavelet modulation, the form of the PS rolling land shake wavelet after PP ripple and the compression is identical, obtain the multi-wave seismic data.

3. the method for claim 1 is characterized in that,

Said step through logging speed modelling initial velocity model comprises: after layer adds a small amount of disturbance with the logging speed model, set up initial velocity model;

Wherein, judge, then after the velocity of longitudinal wave curve calculates, set up initial velocity model through Castagna mode and Gardner mode respectively if the work area of target coal seam does not have shear wave and density logging curve.

4. the method for claim 1 is characterized in that,

Also comprise among the said step B: calculate PP ripple and PS wave reflection coefficient under the average incident angle according to initial velocity model through following formula, generate the theogram of PP ripple and PS ripple respectively

With

Through the amplitude magnitude adjustment PP ripple of composite traces and the amplitude magnitude of PS wave datum body, make that the PS wave amplitude after PP ripple and the compression has comparability; Calculate total residual error S of superposition of data and composite traces _Raw-S _Syn

Wherein, formula is:

$\left\{\begin{array}{c}{r}_{\mathrm{pp}}\left(\mathrm{\&alpha;}\right)\&ap;a\frac{\mathrm{\&Delta;}{v}_p}{v_p}+b\frac{\mathrm{\&Delta;}{v}_s}{v_s}\\ r_{\mathrm{ps}}\left(\mathrm{\&alpha;}\right)\&ap;c\frac{\mathrm{\&Delta;}{v}_p}{v_p}+d\frac{\mathrm{\&Delta;}{v}_s}{v_s}\\ a=\frac{1}{8}(1-4{\mathrm{\&gamma;}}^2{\sin }^2\mathrm{\&alpha;}+\frac{4}{{\cos }^2\mathrm{\&alpha;}})\\ b=-4{\mathrm{\&gamma;}}^2{\sin }^2\mathrm{\&alpha;}\\ c=-\frac{\tan \mathrm{\&beta;}}{8\mathrm{\&gamma;}}(1-2{\mathrm{\&gamma;}}^2{\sin }^2\mathrm{\&alpha;}+2\mathrm{\&gamma;}\cos \mathrm{\&alpha;}\cos \mathrm{\&beta;})\\ d=\frac{\tan \mathrm{\&beta;}}{2\mathrm{\&gamma;}}({4\mathrm{\&gamma;}}^2{\sin }^2\mathrm{\&alpha;}-4\mathrm{\&gamma;}\cos \mathrm{\&alpha;}\cos \mathrm{\&beta;})\end{array}\right.,$

Wherein, Δ v _p, Δ v _sVertical, the shear wave velocity difference of expression between two-layer up and down respectively, v _p, v _sThe average of vertical, the shear wave velocity of expression between two-layer up and down respectively, vertical, shear wave velocity is than γ=v _s/ v _pα representes the average of incident compressional angle and angle of transmission, and β representes the average of transverse wave reflection angle and angle of transmission; S _Raw-S _SynBe PP ripple stack seismic trace

Obtain synthetic seismic trace with inverting

Between residual error and PS ripple stack seismic trace

Obtain synthetic seismic trace with inverting

Between residual error with.

5. the method for claim 1 is characterized in that,

Also comprise among the said step C: vertical, the shear wave impedance of the density calculation initial model that calculates through initial velocity model and Gardner mode

With

Vertical, shear wave velocity model that extrapolation of the log data is obtained multiply each other with density model respectively and obtain

With

And total Residual Z of calculating the inverting surge impedance model that obtains and the extrapolation surge impedance model of logging well _Well-Z _Inv

Wherein, Z _Well-Z _InvThe P wave impedance that the data of extrapolating for logging well obtain

Obtain the P wave impedance with inverting

Between the S wave impedance that obtains of residual error and well logging extrapolation data

Obtain the S wave impedance with inverting

Between residual error with.

6. method as claimed in claim 5 is characterized in that,

Said step D is the objective function T that calculates PP ripple and PS ripple well shake joint inversion through following formula;

Wherein, formula is:

$\left\{\begin{array}{c}T={\mathrm{\&lambda;}}_1\&CenterDot;(S_{\mathrm{raw}}-S_{\mathrm{syn}})+{\mathrm{\&lambda;}}_2\&CenterDot;(Z_{\mathrm{well}}-Z_{\mathrm{inv}})\\ {\mathrm{\&lambda;}}_1+{\mathrm{\&lambda;}}_2=1\\ S_{\mathrm{raw}}-S_{\mathrm{syn}}=(S_{\mathrm{raw}}^{\left(\mathrm{pp}\right)}-S_{\mathrm{syn}}^{\left(\mathrm{pp}\right)})+(S_{\mathrm{raw}}^{\left(\mathrm{ps}\right)}-S_{\mathrm{syn}}^{\left(\mathrm{ps}\right)})\\ Z_{\mathrm{well}}-Z_{\mathrm{inv}}=(Z_{\mathrm{well}}^{\left(p\right)}-Z_{\mathrm{inv}}^{\left(p\right)})+(Z_{\mathrm{well}}^{\left(s\right)}-Z_{\mathrm{inv}}^{\left(s\right)})\end{array}\right.,$

Wherein, weights λ ₁, λ ₂The weight of seismic trace and logging module effect of contraction in the corresponding inverting of difference.

7. method as claimed in claim 6 is characterized in that,

Also comprise in the said step e: after said target function value convergence; Obtain one and reach vertical, the shear wave velocity data volume of well logging resolution and the density data body that calculates through the Gardner mode; Extraction is along the section in coal seam; And obtain the solid coefficient f of the target coal seam on the whole plane through following formula

Wherein, formula is:

$f=\exp ((\mathrm{\&rho;}(v_p^2-2v_s^2)\&CenterDot;(1-\frac{{2\mathrm{\&sigma;}}^2}{1-\mathrm{\&sigma;}})-530.88)/207.19),$

Wherein, ρ is a density, and σ is a Poisson ratio, σ and vertical, shear wave velocity v _pWith v _sBetween relation following:

$\mathrm{\&sigma;}=\frac{0.5{(v_p/v_s)}^2-1}{{(v_p/v_s)}^2-1}.$

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