CN106125138A - Pre-stack CRP gather frequency broadening processing method - Google Patents

Abstract

A method for frequency extension processing of pre-stack CRP gather. According to the frequency spectrum characteristics of seismic waves, the resolution ratio on a seismic time section is improved, and meanwhile, a good signal-to-noise ratio is kept, so that the seismic time section and the signal-to-noise ratio are combined. The method comprises the following steps: the method comprises the following steps: inverting the target interval by using the logging data and the well-side seismic channel; step two: calculating seismic wavelets according to the number of the destination layers in the step one; step three: calculating the energy and frequency distribution range of the original CRP gather; step four: obtaining a noise type according to the energy and frequency distribution range of the original CRP gather; step five: selecting a typical channel and determining a main energy distribution space of the effective wave; step six: determining a CRP frequency extension operator according to the energy, the frequency distribution range and the main energy distribution space of the active wave of the original CRP gather; step seven: and performing frequency extension processing on the CRP gather according to the seismic wavelets, the noise types and the CRP frequency extension operator. The signal-to-noise ratio with good signal-to-noise ratio can be kept; high reliability, good stability and very obvious effect.

Description

The method that frequency processes opened up by a kind of prestack CRP road collection

Technical field

The invention belongs to oil field prospecting field, relate to a kind of road collection processing method, frequency process side opened up by especially CRP road collection Method, the method that frequency processes opened up by a kind of prestack CRP road collection.

Background technology

Along with the raising of Periphery Oilfield exploration and development degree, seism processing faces object and becomes increasingly complex, especially FY oil-layer, oil water relation is complicated, sand-body distribution is scattered, thickness is thin, the most significantly responds, especially T2 on seismic data Reflecting interface screen " cover effect " should be especially prominent and in terms of seismic properties, be also difficult to portray the spatial feature of thin reservoir, How to improve " bottleneck " problem that the earthquake prediction precision always In Oil Field Exploration And Development of this kind of reservoir faces, for this problem, A lot of association areas have been carried out research of technique, particularly tackling key problem in terms of seismic data processing technology and reservoir prediction and have in succession been opened Exhibition, the research work in terms of therefore the quality of pre stack data quality directly affects latter earthquake attribute and reservoir prediction；

Prestack inversion is as the new tool oil field popularization and application the most at home and abroad of reservoir prediction, the reason of numerous prestack inversions Opinion method is mainly the various different approximate expressions to Zoeppritz equation group, and its basic procedure is to utilize CRP road collection number According to, use conventional processing technique cannot obtain high-quality CRP road collection data, the resolution how improving Prestack seismic data becomes The problem making earnest efforts for current people discussing, the resolution of seismic data is low, shows as the deficiency of radio-frequency component in frequency domain or lacks Lose；Although " spectral whitening " that grown up processes and " blue spectrum correction " processing method can preferably solve seismic data The problem that in " effective frequency range ", some radio-frequency component is not enough, but those frequency contents beyond this frequency range have to pass through certain Method just can compensate；

Traditional CRP road collection treatment technology be cannot solve at all keep signal to noise ratio good on time section of earthquake and Resolution, it is the single signal to noise ratio improved on time section of earthquake that traditional CRP road collection processes, and this way is to have lost ground The a lot of effective radio-frequency component of seismic wave, the result obtained by traditional method is that signal to noise ratio increases, but signal to noise ratio is big Amplitude reduction.

Summary of the invention

In order to solve the problems referred to above, the present invention proposes and a kind of can improve earthquake according to the spectral characteristic of seismic wave Good signal to noise ratio is kept while resolution so that the two processing method be combineding with each other, its concrete technology on time section Scheme is as follows:

The method that frequency processes opened up by a kind of prestack CRP road collection, comprises the following steps:

Step one: utilize well-log information and seismic trace near well, inverting interval of interest；

Step 2: calculate seismic wavelet according to the purpose number of plies in step one；

Step 3: calculate the energy of original CRP road collection, frequency distribution scope；

Step 4: according to energy, the frequency distribution scope of original CRP road collection, draw noise types；

Step 5: select typical track, determine significant wave main energetic distribution space；

Step 6: according to energy, frequency distribution scope and the significant wave main energetic distribution space of original CRP road collection, really Determine CRP and open up frequency operator；

Step 7: open up frequency operator according to seismic wavelet, noise types and CRP, carries out opening up frequency on CRP road collection and processes.

Beneficial effects of the present invention: present invention is generally directed to prestack CRP road collection and carry out opening up frequency process, by application the method The CRP road collection resolution obtained and signal to noise ratio all increase substantially, and the various seismic properties for prestack inversion and poststack are ground Study carefully the data volume providing true and reliable；Solve tradition CRP road collection and process asking of both upper signal to noise ratio and resolution mutually restriction Topic；The signal to noise ratio that signal to noise ratio is good can be kept；Reliability height, good stability and effect are the most notable.

Accompanying drawing explanation

Fig. 1 is the original CRP road collection of example；

Fig. 2 be example open up Pin Hou CRP road collection；

Fig. 3 is the original CRP road collection stack result of example；

Fig. 4 be example open up Pin Hou CRP road collection stack result.

Detailed description of the invention

In order to make it easy to understand, below the present invention is further detailed:

Embodiment 1: the method that frequency processes opened up by a kind of prestack CRP road collection, comprises the following steps:

Step one: utilize well-log information and seismic trace near well, inverting interval of interest；

Step 2: calculate seismic wavelet according to the purpose number of plies in step one；

Step 3: calculate the energy of original CRP road collection, frequency distribution scope；

Step 4: according to energy, the frequency distribution scope of original CRP road collection, draw noise types；

Step 5: select typical track, determine significant wave main energetic distribution space；

Step 6: according to energy, frequency distribution scope and the significant wave main energetic distribution space of original CRP road collection, really Determine CRP and open up frequency operator；

Step 7: open up frequency operator according to seismic wavelet, noise types and CRP, carries out opening up frequency on CRP road collection and processes.

CRP road collection is opened up frequency and is based on useful signal and the noise difference at frequency spectrum, and the difference on spatial coherence is carried out SNR estimation and compensation, CRP road collection is opened up the purpose of frequency and is strengthened by useful signal in the range of effective frequency band distribution, simultaneously exactly Abate the noise, provide high-quality CRP road collection data for prestack inversion and poststack attributive analysis；Affect the weight of CRP road collection quality Wanting factor is noise, therefore needs to carry out the collection spectrum sigtral response of CRP road, and noise and useful signal have significantly on spectrum signature Difference, finds out the distribution of noise by analysis；Original CRP road set information is analyzed main in terms of noise, energy, frequency etc. Start with, it is judged that whether original CRP road collection meets the requirement of reservoir prediction and explanation；

If earthquake record has M road, each road to have N number of sampled point, the data of this earthquake record can be with a matrix X table Show:

X=[x_ij], i=1,2 ..., M；J=1,2 ..., N

Wherein i represents that Taoist monastic name, j represent sampled point sequence number；According to matrix theory, any one M × N matrix just can made Hand over and decompose, it may be assumed that

X=U ∑ V^T (1-1)

U and V is respectively M × M and N × N rank orthogonal matrix, and ∑ is M × N matrix；If all row of matrix U are by covariance matrix XX^TEach characteristic vector (M dimension) formed, V is by X^TEach characteristic vector (N-dimensional) composition of X, then ∑ is M × N diagonal matrix, main diagonal angle Element is by singular value σ of X_i(XX^TOr X^TIth feature value λ of X_iNon-negative square root) composition, off-diagonal element is all zero, this Time (2-1) formula be called the singular value decomposition of matrix X；

(1-1) formula can also

$\begin{array}{c}X=U\ΣV^T\\ =\underset{i=1}{\overset{r}{\Σ}}{\mathrm{\σ}}_i{u}_i{v_i}^T\end{array}---\left(1-2\right)$

Here r is the order of matrix X, u_iFor XX^TCorresponding to σ_iCharacteristic vector, v_iFor X^TX corresponds to σ_iCharacteristic vector；A M × N matrix, the ith feature of referred to as X as；Obviously, the singular value decomposition formula of matrix X is not unique, in order to The convenience used, the diagonal element of our regulation diagonal matrix ∑ is by the order arrangement successively decreased, it may be assumed that

σ₁>σ₂>…>σ_r>0

When M road is separate, r=min (M, N), generally, r≤min (M, N)；The Frobenius model of matrix X Number is defined as:

$\left|\right|X|{|}_F={\left(\underset{i,j}{\Σ}|x_{ij}{|}^F\right)}^{1/F}---\left(1-3\right)$

Taking F and be equal to 2, above formula becomes:

$\left|\right|X|{|}_2={\left(\underset{i,j}{\Σ}|x_{ij}{|}^2\right)}^{1/2}---\left(1-4\right)$

Being known by (1-4) formula, the F norm (as F=2) of matrix actually reflects the gross energy of M road earthquake record；Permissible Prove:

$\left|\right|X|{|}_2^2=\underset{i=1}{\overset{r}{\Σ}}{\mathrm{\σ}}_i^2---\left(1-5\right)$

This shows the gross energy of M road earthquake record, covariance matrix eigenvalue equal to X (or the singular value of X square) Sum；

If M < N, when M Seismic Traces linear independence, σ_j(j=1,2 ..., M) all it is not zero, so X's is the heaviest Structure need all of feature as；When M the Seismic Traces linear correlation of X, the most only σ₁Being not zero, the Perfect Reconstruction of X only needs Want first feature picture；Seismic channel dependency is the best, reconstruct this record required for feature as the fewest；

If being only recorded as X by front P feature as approximate reconstruction X, the earthquake of reconstruction_P, then:

$X_P=\underset{i=1}{\overset{P}{\&Sigma;}}{\mathrm{\&sigma;}}_i{u}_i{v}^T---\left(1-6\right)$

X_PGross energy be:

$\left|\right|X_P|{|}_2^2=\underset{i=1}{\overset{P}{\&Sigma;}}{\mathrm{\&sigma;}}_i^2---\left(1-7\right)$

Reconstruction error is:

$\mathrm{\&epsiv;}=\underset{i=P+1}{\overset{r}{\&Sigma;}}{\mathrm{\&sigma;}}_i^2---\left(1-8\right)$

Wherein (1-6) is CRP road collection and opens up frequency operator.

Along with going deep into of degree of prospecting, microstructures, lithological reservoir exploration become to be the theme, hold up poplar river channel sand identification Problem day by day highlights, and the resolution that common seismic processes is the most inadequate, and earthquake is opened up frequency technology and is thus lifted to the most highly carry out Exploratory development, the present invention proposes CRP road collection and opens up frequency treatment technology, it is therefore an objective to, thing little for middle-shallow strata reservoir sand body scope Property change is fast, resource potential greatly, the difficult feature of oil reservoir identification, put the difficult point of High Resolution Seismic Technology in order, explore guarantor's panel height and divide Resolution opens up frequency treatment technology, Study of Thin alternating layers identification and description technique, improves the seismic technology identification ability to thin reservoir, is formed Counter-techniques scheme, services fine granularing scalability developmental research, provides high-quality for prestack AVO inverting, poststack attributes research Shake data.

Specific embodiment: combine Fig. 1, in certain road, work area collection data, its Reservoir Section be mainly distributed on 1000ms-1200ms it Between, in terms of original road set analysis, its vertical, horizontal energy coincidence is preferable, but the lineups layering near main purpose layer is relatively Difference, especially signal to noise ratio and resolution all ratios are relatively low, have some random noises, these Ye Shi roads concentrate the phenomenon that generally exists because of This, improve being critical that lineups level as far as possible and suppressing noise as far as possible of road collection quality；Dao Jite according to this area Levying, window size and maximum upper and lower time shift amount during definition contrast, it is that crucial process of collection level can that suitable parameter adjusts repeatedly To improve resolution and the signal to noise ratio of CRP road collection to a certain extent.In conjunction with Fig. 2, it it is the result CRP road after processing by the present invention Collection, and collection contrast in original road is it is apparent that the reflected energy of prestack road collection substantially presents the feature of horizontal distribution, differentiates Rate and signal to noise ratio are all greatly improved.

Beneficial effect: can keep the signal to noise ratio that signal to noise ratio is good, reliability height, good stability and effect are the most notable. The signal to noise ratio keeping good on time section of earthquake while resolution can improved according to the spectral characteristic of seismic wave, making It is combined with each other both.

Claims (1)

1. the method that frequency processes opened up by a prestack CRP road collection, it is characterised in that comprise the following steps:

Step one: utilize well-log information and seismic trace near well, inverting interval of interest；

Step 2: calculate seismic wavelet according to the purpose number of plies in step one；

Step 3: calculate the energy of original CRP road collection, frequency distribution scope；

Step 4: according to energy, the frequency distribution scope of original CRP road collection, draw noise types；

Step 5: select typical track, determine significant wave main energetic distribution space；

Step 6: according to energy, frequency distribution scope and the significant wave main energetic distribution space of original CRP road collection, determine CRP Open up frequency operator；

Step 7: open up frequency operator according to seismic wavelet, noise types and CRP, carries out opening up frequency on CRP road collection and processes.