CN107367760B - Based on the surface-related multiple and higher-order spectra method and system for accelerating linear Bregman algorithm - Google Patents
Based on the surface-related multiple and higher-order spectra method and system for accelerating linear Bregman algorithm Download PDFInfo
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Abstract
Description
技术领域technical field
本发明涉及地震勘探领域,尤其涉及地震勘探技术中地震信号处理方面,更具体地说,涉及一种基于加速线性Bregman算法的表面多次波和子波估计方法及系统。The invention relates to the field of seismic exploration, in particular to seismic signal processing in seismic exploration technology, and more particularly to a method and system for estimating surface multiples and wavelets based on accelerated linear Bregman algorithm.
背景技术Background technique
多次反射波(多次波)相关问题是反射地震勘探中普遍存在的最突出的问题之一。由于海水表面是一个强反射界面,表面相关多次波问题在海洋地震勘探中尤为严重。当今海上石油天然气可燃冰资源勘探和开发已经成为国内外各大石油能源公司的当务之急。我国南海石油天然气可燃冰资源丰富,是当前海洋勘探的热点和焦点。在目前石油工业生产中,常规的地震数据处理技术的一个基本假设是:输入的反射数据体仅由一次反射波(一次波)组成。多次波会被错误地认为是一次波或者混合在一次波中的一部分。多次波从而对一次波的处理和成像造成强烈干扰,影响资源勘探,所以多次波估计技术具有极好的实际工业应用前景。The problem related to multiple reflections (multiples) is one of the most prominent problems commonly existing in reflection seismic exploration. Because the sea surface is a strong reflection interface, the problem of surface-related multiples is particularly serious in marine seismic exploration. Today, the exploration and development of offshore oil and natural gas combustible ice resources has become the top priority of major oil and energy companies at home and abroad. The South my country Sea is rich in oil and natural gas combustible ice resources, which is the hot spot and focus of current ocean exploration. In the current oil industry production, a basic assumption of conventional seismic data processing technology is that the input reflection data volume is composed of only one reflected wave (primary wave). Multiples can be mistakenly identified as primary waves or as part of a mixture of primary waves. The multiple waves thus cause strong interference to the processing and imaging of the primary waves and affect the resource exploration. Therefore, the multiple wave estimation technology has excellent practical industrial application prospects.
目前工业界采用的多次波估计或压制方法主要分为下面几类:一类利用多次波与一次波的特征差异压制多次波,称为滤波法;一类首先从地震数据中预测出多次波,然后将其从原始数据中自适应减去,称为预测相减法;还有一种逆散射级数法压制多次波。At present, the multiple wave estimation or suppression methods used in the industry are mainly divided into the following categories: one type uses the characteristic difference between multiple waves and primary waves to suppress multiple waves, which is called filtering method; one type is first predicted from seismic data. Multiples are then adaptively subtracted from the original data, known as predictive subtraction; there is also an inverse scattering series method to suppress multiples.
滤波法以多次波和一次波在特定变换域中具有明显的特征差异为前提假设,通过设计各种数学算法来获取这种差异并消除多次波。滤波法利用的主要特征差异包括多次波的周期性和可分离性。滤波类方法在应用于一些复杂构造的多次波衰减时,会遇到多次波和一次波之间的特征差异很小或者是没有差异的情况,这时滤波类方法适用的前提条件得不到满足,多次波压制效果不明显。The filtering method assumes that multiples and primarys have obvious characteristic differences in a specific transform domain, and designs various mathematical algorithms to obtain such differences and eliminate multiples. The main characteristic differences exploited by filtering methods include the periodicity and separability of the multiples. When the filtering method is applied to the attenuation of some complex structures of multiples, the characteristic difference between the multiple and the primary wave is small or no difference. To satisfy, the multiple wave suppression effect is not obvious.
逆散射级数预测多次波也存在一些问题:计算量大、成本高;难以预测远偏移距的多次波;复杂介质中多次波的预测能力也有一定局限。这其中,计算成本高使得这一方法很难应用于实际资料的处理当中。There are also some problems in the prediction of multiples by inverse scattering series: large amount of calculation and high cost; it is difficult to predict multiples at long offsets; the prediction ability of multiples in complex media also has certain limitations. Among them, the high computational cost makes this method difficult to apply to actual data processing.
Berkhout于1982年提出了描述复杂多次波的反馈模型理论,奠定了反馈迭代多次波压制方法的数学物理基础,但消除多次波时需要已知震源子波。为了说明此问题,以及便于后续说明,我们先来介绍与本发明密切相关的反馈模型公式,也即Berkhout proposed a feedback model theory to describe complex multiples in 1982, which laid the mathematical and physical foundation of the feedback iterative multiple suppression method, but to eliminate multiples requires known source wavelets. In order to illustrate this problem and facilitate subsequent descriptions, we first introduce the feedback model formula that is closely related to the present invention, that is,
其中,D为采集到的输入数据的时间域的矩阵表达形式,为D经傅里叶正变换后频率域的矩阵表达式的一个切片,S为待估计的震源子波的时间域的矩阵表达式,为S经傅里叶正变换后频率域的矩阵表达式的一个切片,G为格林函数(也即不含多次波的地下脉冲响应)的时间域的矩阵表达式,为G经傅里叶正变换后频率域的矩阵表达式的一个切片我们用^符号来表示频率域的数据或变量,rsurf为空气与水的接触面的反射系数,假定rsurf=-1,其中和的频率域乘积(也即时域褶积)代表估计的一次波的频率的切片,也即其中为一次波的频率域的一个切片。本发明中所涉及的一次波是指除表面多次波之外的所有波,也即这里的一次波包含了层间多次波(其与表面无关)。表示估计的表面多次波的频率域的一个切片,也即数据作为二次震源向下传播,同地下脉冲响应格林函数的频率域乘积(时域褶积)来预测表面相关多次波频率域的切片。由方程1式可以看出精确的表面多次波估计依赖于估计的震源子波的精准度。Among them, D is the matrix expression form of the collected input data in the time domain, is a slice of the matrix expression in the frequency domain after the forward Fourier transformation of D, S is the matrix expression in the time domain of the source wavelet to be estimated, is a slice of the matrix expression in the frequency domain after the forward Fourier transformation of S, G is the matrix expression in the time domain of the Green's function (that is, the subsurface impulse response without multiples), It is a slice of the matrix expression in the frequency domain after the forward Fourier transformation of G. We use the ^ symbol to represent the data or variables in the frequency domain, r surf is the reflection coefficient of the contact surface between air and water, assuming r surf =-1 ,in and The frequency-domain product of (also called the time-domain convolution) represents a slice of the estimated frequency of the primary wave, namely in is a slice of the frequency domain of the primary wave. The primary waves involved in the present invention refer to all waves except the surface multiples, that is, the primary waves here include the interlayer multiples (which have nothing to do with the surface). represents a slice of the frequency domain of the estimated surface multiples, i.e. the data Propagating downward as a secondary source, the same subsurface impulse responds to the Green's function The frequency-domain product of (time-domain convolution) is used to predict slices in the frequency domain of surface-correlated multiples. It can be seen from Equation 1 that accurate surface multiple estimation depends on the accuracy of the estimated source wavelets.
Verschuur等在1992年提出了表面相关多次波压制技术SRME,其通过引入基于一次波能量最小假设的自适应相减,从实际数据中估计震源子波。为了避免由于求解震源子波而产生的非线性问题,Berkhout和Verschuur在1997年提出迭代SRME方法。一次波能量最小这一前提假设条件并不是在所有的情况下都能够满足。另外,在实际应用中,SRME还存在自适应预测相减损害有效信号的问题。Verschuur et al. proposed the surface correlated multiple suppression technique SRME in 1992, which estimated the source wavelet from the actual data by introducing an adaptive subtraction based on the assumption of minimum primary wave energy. In order to avoid the nonlinear problem caused by solving the source wavelet, Berkhout and Verschuur proposed the iterative SRME method in 1997. The premise of the minimum primary wave energy is not satisfied in all cases. In addition, in practical applications, SRME also has the problem that the effective signal is damaged by adaptive prediction and subtraction.
为了改进SRME存在预测相减损害有效信号的问题,van Groenestijn和Verschuur在2009年提出稀疏反演一次波估计技术,也即EPSI。为了改善EPSI中存在的问题,Lin和Herrmann于2013年提出了稳健的稀疏反演一次波估计技术,也即REPSI。EPSI和REPSI是与本发明较为相关的现有技术,他们的技术方案和存在的问题、缺点将在下面进行详细地阐述。In order to improve the problem that SRME has the problem of predicting subtractive damage to the effective signal, van Groenestijn and Verschuur proposed the sparse inversion primary wave estimation technique, or EPSI, in 2009. In order to improve the existing problems in EPSI, Lin and Herrmann proposed a robust sparse inversion primary wave estimation technique, namely REPSI, in 2013. EPSI and REPSI are the prior art relatively related to the present invention, and their technical solutions, existing problems and shortcomings will be described in detail below.
此外,由于实际野外地震数据采集时,每炮所激发的震源子波不尽相同,而目前所有的多次波估计方法均假设所有的震源子波相同,影响多次波估计精度,而本发明可估计随炮集空间位置变化的震源子波。In addition, when the actual field seismic data is collected, the source wavelets excited by each shot are not the same, and all the current multiple wave estimation methods assume that all the source wavelets are the same, which affects the multiple wave estimation accuracy. The source wavelet can be estimated as a function of the spatial position of the shot collection.
由于多次波估计时每次迭代耗费的计算资源(内存、处理器)较多、计算时间较长,除了提高多次波、震源子波的估计精度外,提高方法的效率、提升算法的收敛速率、简化算法的复杂度、减少方法的调节参数,也是多次波估计技术的发展趋势。Since each iteration consumes a lot of computing resources (memory, processor) and takes a long time to estimate multiples, in addition to improving the estimation accuracy of multiples and source wavelets, the efficiency of the method and the convergence of the algorithm are improved. The rate, the complexity of the simplified algorithm, and the adjustment parameters of the reduction method are also the development trend of multiple estimation technology.
与本发明相关的现有技术介绍如下。The prior art related to the present invention is described below.
现有技术一的技术方案The technical solution of the prior art
van Groenestijn和Verschuur于2009年在SRME的理论基础上提出了稀疏反演一次波估计方法EPSI,该方法在迭代反演过程中,以拟合数据残差为驱动,通过最速下降法交替更新地下脉冲响应G与震源子波S两个未知参数,进而重构一次波及其对应的表面相关多次波与SRME相比,EPSI避免了自适应相减的步骤,更好地保护了一次波有效信号。In 2009, van Groenestijn and Verschuur proposed the sparse inversion primary wave estimation method EPSI based on the theoretical basis of SRME. In the iterative inversion process, the method is driven by the residual of the fitted data and alternately updates the subsurface pulse through the steepest descent method. Response to two unknown parameters G and source wavelet S, and then reconstruct the primary wave and its corresponding surface-correlated multiples Compared with SRME, EPSI avoids the step of adaptive subtraction and better protects the effective signal of primary wave.
van Groenestijn和Verschuur的EPSI方法在进行震源子波估计时,假定所有的震源子波相同,并没有给出随炮集空间位置变化震源子波的估计方案(也即常子波估计)。本发明可估计随炮集空间位置变化震源子波。The EPSI method of van Groenestijn and Verschuur assumes that all source wavelets are the same when estimating source wavelets, and does not provide an estimation scheme for source wavelets that vary with the spatial position of the shot collection (ie, constant wavelet estimation). The invention can estimate the source wavelet which changes with the spatial position of the shot collection.
为了保证地下脉冲响应G在时域的稀疏性,EPSI在更新脉冲响应G的过程中,按照时间由小到大、振幅由强到弱的顺序更新脉冲。也即为了促进地下脉冲响应G的时域稀疏性,EPSI方法设计了众多人为调节参数,比如EPSI需要确定:一个时间窗,用来判定格林函数的更新范围(也即时间窗内的进行更新,时间窗外的置零);每次迭代时格林函数中反射同相轴的个数,等。正如Lin和Herrmann在2013年论文中所指出:即便精确地知道了地下反射界面的个数(实际中我们不可能知道),EPSI方法也并不能充分利用这一先验信息。EPSI的地下脉冲响应更新,容易受到脉冲选取窗口和拾取数量等参数的影响,进而影响多次波估计精度。从本质上来讲,EPSI方法中格林函数的稀疏度是由人为来控制的,而不是由数学优化算法来控制。这一缺点限制了EPSI方法在实际工业中的应用。In order to ensure the sparsity of the subsurface impulse response G in the time domain, EPSI updates the impulses in the order of time from small to large and amplitude from strong to weak in the process of updating the impulse response G. That is to say, in order to promote the time-domain sparsity of the underground impulse response G, the EPSI method has designed many artificial adjustment parameters. For example, EPSI needs to determine: a time window to determine the update range of the Green's function (that is, the update within the time window, zeroing outside the time window); the number of reflection events in the Green's function per iteration, etc. As Lin and Herrmann pointed out in their 2013 paper: Even if the number of subsurface reflecting interfaces is known precisely (which we cannot actually know), the EPSI method cannot fully utilize this prior information. The update of the subsurface impulse response of EPSI is easily affected by parameters such as the pulse selection window and the number of pickups, which in turn affects the estimation accuracy of multiples. Essentially, the sparsity of the Green's function in the EPSI method is controlled by humans rather than by mathematical optimization algorithms. This shortcoming limits the application of EPSI method in practical industry.
与本发明相关的现有技术二Prior art two related to the present invention
基于EPSI相同的理论(也即反馈模型1式),Lin和Herrmann在2013年将EPSI地下脉冲响应的稀疏约束条件修改为一范数约束,并采用谱映射梯度一范数算法来求解得到稀疏的地下脉冲响应格林函数,在一定程度上提高了原始EPSI方法的稳定性。Lin和Herrmann在2013年所提出方法被命名为Robust EPSI(REPSI)。Lin和Herrmann所提出的REPSI方法,同EPSI一样,也是交替更新地下脉冲响应G与震源子波S两个未知参数,进而重构一次波及其对应的表面相关多次波EPSI和REPSI的最大区别在于:EPSI中格林函数的稀疏度多数由人为调节参数来控制,而REPSI则是采用了数学优化算法来求解得到稀疏的地下脉冲响应格林函数。Based on the same theory of EPSI (that is, feedback model 1), Lin and Herrmann in 2013 modified the sparse constraint of EPSI subsurface impulse response to a one-norm constraint, and adopted the spectral mapping gradient one-norm algorithm To solve the sparse underground impulse response Green's function, the stability of the original EPSI method is improved to a certain extent. The method proposed by Lin and Herrmann in 2013 was named Robust EPSI (REPSI). The REPSI method proposed by Lin and Herrmann, like EPSI, also alternately updates the two unknown parameters of the subsurface impulse response G and the source wavelet S, and then reconstructs the primary wave and its corresponding surface-correlated multiples The biggest difference between EPSI and REPSI is that the sparsity of Green's function in EPSI is mostly controlled by artificial adjustment parameters, while REPSI uses Mathematical optimization algorithm to solve the Green's function to obtain the sparse subsurface impulse response.
Lin和Herrmann的REPSI方法在进行震源子波估计时,同样假定所有的震源子波相同,也并没有给出随炮集空间位置变化震源子波的估计方案(也即常子波估计)。本发明可估计随炮集空间位置变化震源子波。此外,REPSI在进行常子波估计时,采用LSQR算法来迭代求解得到震源子波,大大增加了方法的计算量、降低了效率。而本发明一步即可估计得到震源子波。Lin and Herrmann's REPSI method also assumes that all source wavelets are the same when estimating source wavelets, and does not provide an estimation scheme for source wavelets (ie, constant wavelet estimation) that varies with the spatial position of the shot collection. The invention can estimate the source wavelet which changes with the spatial position of the shot collection. In addition, REPSI uses the LSQR algorithm to iteratively solve the source wavelet when estimating the constant wavelet, which greatly increases the computational complexity and reduces the efficiency of the method. In the present invention, the source wavelet can be estimated and obtained in one step.
Lin和Herrmann的REPSI方法的另一个重要缺点是:其依赖一个极为复杂的谱映射梯度一范数算法来求解得到稀疏的地下脉冲响应格林函数。是一个开源的MATLAB程序,可以通过访问https://github.com/mpf/spgl1来下载。算法的复杂度主要体现在:众多调节参数、众多子函数、上千行代码。斯伦贝谢(Schlumberger)油田服务公司曾尝试改编将其在实际工业中应用,但是碍于算法的复杂性,最终并未成功。算法的复杂度也同时降低了REPSI方法的效率、阻碍了REPSI方法在工业中的实际应用。Another important disadvantage of Lin and Herrmann's REPSI method is that it relies on an extremely complex gradient-norm algorithm for spectral mapping to solve the Green's function for the sparse subsurface impulse response. is an open source MATLAB program that can be downloaded by visiting https://github.com/mpf/spgl1. The complexity of the algorithm is mainly reflected in: many adjustment parameters, many sub-functions, and thousands of lines of code. Schlumberger oilfield services tried to adapt apply it in the actual industry, but due to the The complexity of the algorithm was ultimately unsuccessful. The complexity of the algorithm also reduces the efficiency of the REPSI method and hinders the practical application of the REPSI method in the industry.
发明内容SUMMARY OF THE INVENTION
本发明要解决的技术问题在于,针对上述的现有技术中EPSI和REPSI存在的技术缺陷,提供了一种基于加速线性Bregman算法的表面多次波和子波估计方法及系统。The technical problem to be solved by the present invention is to provide a method and system for estimating surface multiples and wavelets based on the accelerated linear Bregman algorithm, aiming at the above-mentioned technical defects of EPSI and REPSI in the prior art.
根据本发明的其中一方面,本发明为解决其技术问题,提供了一种基于加速线性Bregman算法的表面多次波和子波估计方法,包含下述步骤:According to one aspect of the present invention, in order to solve its technical problem, the present invention provides a method for estimating surface multiples and wavelets based on accelerated linear Bregman algorithm, comprising the following steps:
S1、使用下述的步骤S11以及S12交替更新待估计的格林函数与待估计的震源子波直至达到预设次数,其中首次进行步骤S11的待估计的震源子波具有预设的初始值:S1, use the following steps S11 and S12 to alternately update the Green's function to be estimated and the source wavelet to be estimated until reaching a preset number of times, wherein the source wavelet to be estimated that performs step S11 for the first time has a preset initial value:
S11、根据待估计的震源子波以及采集的输入数据,采用加速线性Bregman算法更新待估计的格林函数;S11. According to the source wavelet to be estimated and the collected input data, use the accelerated linear Bregman algorithm to update the Green's function to be estimated;
S12、根据更新后的待估计的格林函数以及所述输入数据,采用下述公式更新待估计的震源子波;S12, according to the updated Green's function to be estimated and the input data, adopt the following formula to update the source wavelet to be estimated;
当待估计的震源子波不随炮集空间位置变化时:When the source wavelet to be estimated does not change with the spatial position of the shot collection:
当待估计的震源子波随炮集空间位置变化时:When the source wavelet to be estimated changes with the spatial position of the shot collection:
S2、根据最终更新后的结果,得出震源子波以及表面多次波中至少一种的估计结果;S2. According to the final updated result, obtain the estimation result of at least one of the source wavelet and the surface multiple waves;
其中,上标est表示待估计,代表震源子波矩阵切片的对角线上的元素,j表示随炮集空间位置或炮集编号,vec()表示将一个矩阵变为列向量,下标代表取一个频率切片矩阵的第j列,下标代表取一个频率切片矩阵的所有列,为输入数据的频率域的矩阵表达式的切片,为震源子波的频率域的矩阵表达式的切片,rsurf为空气与水的接触面的反射系数,为格林函数的频率域的矩阵表达式的切片。Among them, the superscript est means to be estimated, Represents the elements on the diagonal of the source wavelet matrix slice, j represents the spatial position of the shot set or the shot set number, vec() represents the transformation of a matrix into a column vector, and the subscript Represents taking the jth column of a frequency slice matrix, subscript represents taking all columns of a frequency slice matrix, is a slice of a matrix expression in the frequency domain of the input data, is the slice of the matrix expression in the frequency domain of the source wavelet, r surf is the reflection coefficient of the contact surface between air and water, A slice of the matrix expression in the frequency domain for the Green's function.
进一步的,在本发明的基于加速线性Bregman算法的表面多次波和子波估计方法中,根据待估计的震源子波以及采集的输入数据,采用加速线性Bregman算法更新待估计的格林函数具体的包括:Further, in the method for estimating surface multiples and wavelets based on the accelerated linear Bregman algorithm of the present invention, according to the source wavelet to be estimated and the collected input data, the accelerated linear Bregman algorithm is used to update the Green's function to be estimated, which specifically includes: :
根据公式 及进行迭代,依次求出y1、x1、y2、x2、y3…、其中,为本次执行步骤S11后的待估计的格林函数的更新结果的时间域的向量表达形式,lmax为本次执行步骤S11时的加速线性Bregman算法的最大迭代次数;According to the formula and Iterate to find y 1 , x 1 , y 2 , x 2 , y 3 …, in, is the vector representation in the time domain of the update result of the Green's function to be estimated after step S11 is executed this time, and lmax is the maximum number of iterations of the accelerated linear Bregman algorithm when step S11 is executed this time;
式中,x0、与y0均等于待估计的格林函数的预设的初始值的时间域的向量表达形式,观测数据向量b为所述输入数据的时间域的向量表达形式,t代表的是步长,其表达式为:In the formula, x 0 , and y 0 are both equal to the vector representation in the time domain of the preset initial value of the Green's function to be estimated, and the observation data vector b is the vector representation in the time domain of the input data, t represents the step size, and its expression is:
映射函数∏σ(Axl-b)的定义为:The mapping function ∏ σ (Ax l -b) is defined as:
软阈值函数shrink(x,μ)定义为:The soft threshold function shrink(x, μ) is defined as:
shrink(x,μ)=max(|x|-μ,0)sign(x),shrink(x,μ)=max(|x|-μ,0)sign(x),
其中,σ代表噪声水平因子,max()函数表示取最大值,||函数表示取绝对值,sign(x)表示符号取值函数;Among them, σ represents the noise level factor, the max() function represents the maximum value, the || function represents the absolute value, and sign(x) represents the sign value function;
矩阵算子A表示进行下述操作的操作集合:将待估计的格林函数由时间域的向量表形式进行傅里叶变换变为频率域的向量表形式,将待估计的格林函数由频率域的向量表形式变为频率域的矩阵表形式,根据公式分别计算输入数据对应的模拟数据的频率域的矩阵表达形式的各个切片根据各个切片进行反傅里叶变换得到输入数据对应的模拟数据的时间域的向量表达形式。The matrix operator A represents a set of operations to perform the following operations: Fourier transform the Green's function to be estimated from a vector table in the time domain to a vector table in the frequency domain, and convert the Green's function to be estimated from the frequency domain. The vector table form becomes the matrix table form in the frequency domain, according to the formula Calculate each slice of the matrix representation of the frequency domain of the analog data corresponding to the input data separately According to each slice Inverse Fourier transform is performed to obtain the vector representation in the time domain of the analog data corresponding to the input data.
进一步的,在本发明的基于加速线性Bregman算法的表面多次波和子波估计方法中,步骤S2中,Further, in the method for estimating surface multiples and wavelets based on the accelerated linear Bregman algorithm of the present invention, in step S2,
震源子波的估计结果根据最后一次更新待估计的震源子波的结果得到;The estimation result of the source wavelet is obtained according to the result of the last update of the source wavelet to be estimated;
表面多次波的估计结果根据m=rsurfg*d得到,m为表面多次波的时间域的向量表达形式,g为格林函数的时间域的向量表达形式,d为输入数据的时间域的向量表达形式。The estimation result of the surface multiples is obtained according to m=r surf g*d, where m is the vector representation in the time domain of the surface multiples, g is the vector representation in the time domain of the Green’s function, and d is the time domain of the input data vector representation of .
进一步的,在本发明的基于加速线性Bregman算法的表面多次波和子波估计方法中,若待估计的格林函数已经达到最大更新次数而待估计的震源子波未达到最大更新次数,则再次进行步骤S11时,lmax被更新为待估计的震源子波的最大更新次数减去已经更新的次数后的差值,且之前每次执行步骤S11时的lmax相等;若待估计的震源子波已经达到最大更新次数而待估计的格林函数未达到最大更新次数,则后续只进行一次步骤S12,且每次执行步骤S11时的lmax相等。Further, in the method for estimating surface multiples and wavelets based on the accelerated linear Bregman algorithm of the present invention, if the Green's function to be estimated has reached the maximum number of updates and the source wavelet to be estimated has not reached the maximum number of updates, then carry out again. In step S11, lmax is updated to the difference between the maximum update times of the source wavelet to be estimated minus the number of times that have been updated, and the lmax when step S11 is executed before each time is equal; if the source wavelet to be estimated If the maximum number of updates has been reached but the Green's function to be estimated has not reached the maximum number of updates, then step S12 is performed only once, and lmax is the same each time step S11 is performed.
本发明为解决其技术问题,还提供了一种基于加速线性Bregman算法的表面多次波和子波估计系统,包含:In order to solve the technical problem, the present invention also provides a surface multiple wave and wavelet estimation system based on accelerated linear Bregman algorithm, including:
交替更新单元,用于使用下述的格林函数更新单元以及震源子波更新单元交替更新待估计的格林函数与待估计的震源子波直至达到预设次数,其中首次调用格林函数更新单元的待估计的震源子波具有预设的初始值:The alternate update unit is used to alternately update the Green's function to be estimated and the source wavelet to be estimated by using the following Green's function update unit and the source wavelet update unit until a preset number of times is reached, wherein the Green's function update unit to be estimated is called for the first time. The hypocenter wavelet has preset initial values:
格林函数更新单元,根据待估计的震源子波以及采集的输入数据,采用加速线性Bregman算法更新待估计的格林函数;The Green's function updating unit adopts the accelerated linear Bregman algorithm to update the Green's function to be estimated according to the source wavelet to be estimated and the collected input data;
震源子波更新单元,根据更新后的待估计的格林函数以及所述输入数据,采用下述公式更新待估计的震源子波;The source wavelet updating unit adopts the following formula to update the source wavelet to be estimated according to the updated Green's function to be estimated and the input data;
当待估计的震源子波不随炮集空间位置变化时:When the source wavelet to be estimated does not change with the spatial position of the shot collection:
当待估计的震源子波随炮集空间位置变化时:When the source wavelet to be estimated changes with the spatial position of the shot collection:
估计结果获取单元,用于根据最终更新后的结果,得出待估计的震源子波以及待估计的表面多次波中的至少一种的估计结果;an estimation result obtaining unit, configured to obtain an estimation result of at least one of the source wavelet to be estimated and the surface multiple to be estimated according to the final updated result;
其中,上标est表示待估计,代表震源子波矩阵切片的对角线上的元素,j表示随炮集空间位置或炮集编号,vec()表示将一个矩阵变为列向量,下标代表取一个频率切片矩阵的第j列,下标代表取一个频率切片矩阵的所有列,为输入数据的频率域的矩阵表达式的切片,为震源子波的频率域的矩阵表达式的切片,rsurf为空气与水的接触面的反射系数,为格林函数的频率域的矩阵表达式的切片。Among them, the superscript est means to be estimated, Represents the elements on the diagonal of the source wavelet matrix slice, j represents the spatial position of the shot set or the shot set number, vec() represents the transformation of a matrix into a column vector, and the subscript Represents taking the jth column of a frequency slice matrix, subscript represents taking all columns of a frequency slice matrix, is a slice of a matrix expression in the frequency domain of the input data, is the slice of the matrix expression in the frequency domain of the source wavelet, r surf is the reflection coefficient of the contact surface between air and water, A slice of the matrix expression in the frequency domain for the Green's function.
进一步的,在本发明的基于加速线性Bregman算法的表面多次波和子波估计系统中,根据待估计的震源子波以及采集的输入数据,采用加速线性Bregman算法更新待估计的格林函数具体的包括:Further, in the surface multiple wave and wavelet estimation system based on the accelerated linear Bregman algorithm of the present invention, according to the source wavelet to be estimated and the collected input data, the accelerated linear Bregman algorithm is used to update the Green's function to be estimated, which specifically includes: :
根据公式及进行迭代,依次求出y1、x1、y2、x2、y3…、其中,为本次执行步骤S11后的待估计的格林函数的更新结果的时间域的向量表达形式,lmax为本次执行步骤S11时的加速线性Bregman算法的最大迭代次数;According to the formula and Iterate to find y 1 , x 1 , y 2 , x 2 , y 3 …, in, is the vector representation in the time domain of the update result of the Green's function to be estimated after step S11 is executed this time, and lmax is the maximum number of iterations of the accelerated linear Bregman algorithm when step S11 is executed this time;
式中,x0、与y0均等于待估计的格林函数的预设的初始值的时间域的向量表达形式,观测数据向量b为所述输入数据的时间域的向量表达形式,tl代表的是步长,其表达式为:In the formula, x 0 , and y 0 are both equal to the vector representation in the time domain of the preset initial value of the Green's function to be estimated, and the observation data vector b is the vector representation in the time domain of the input data, t l represents the step size, and its expression is:
映射函数∏σ(Axl-b)的定义为:The mapping function ∏ σ (Ax l -b) is defined as:
软阈值函数shrink(x,μ)定义为:The soft threshold function shrink(x, μ) is defined as:
shrink(x,μ)=max(|x|-μ,0)sign(x),shrink(x,μ)=max(|x|-μ,0)sign(x),
其中,σ代表噪声水平因子,max()函数表示取最大值,||函数表示取绝对值,sign(x)表示符号取值函数;Among them, σ represents the noise level factor, the max() function represents the maximum value, the || function represents the absolute value, and sign(x) represents the sign value function;
矩阵算子A表示进行下述操作的操作集合:将待估计的格林函数由时间域的向量表形式进行傅里叶变换变为频率域的向量表形式,将待估计的格林函数由频率域的向量表形式变为频率域的矩阵表形式,根据公式分别计算输入数据对应的模拟数据的频率域的矩阵表达形式的各个切片根据各个切片进行反傅里叶变换得到输入数据对应的模拟数据的时间域的向量表达形式。The matrix operator A represents a set of operations to perform the following operations: Fourier transform the Green's function to be estimated from a vector table in the time domain to a vector table in the frequency domain, and convert the Green's function to be estimated from the frequency domain. The vector table form becomes the matrix table form in the frequency domain, according to the formula Calculate each slice of the matrix representation of the frequency domain of the analog data corresponding to the input data separately According to each slice Inverse Fourier transform is performed to obtain the vector representation in the time domain of the analog data corresponding to the input data.
进一步的,在本发明的基于加速线性Bregman算法的表面多次波和子波估计系统中,估计结果获取单元中,Further, in the surface multiple and wavelet estimation system based on the accelerated linear Bregman algorithm of the present invention, in the estimation result obtaining unit,
震源子波的估计结果根据最后一次更新待估计的震源子波的结果得到;The estimation result of the source wavelet is obtained according to the result of the last update of the source wavelet to be estimated;
表面多次波的估计结果根据m=rsurfg*d得到,m为表面多次波的时间域的向量表达形式,g为格林函数的时间域的向量表达形式,d为输入数据的时间域的向量表达形式。The estimation result of the surface multiples is obtained according to m=r surf g*d, where m is the vector representation in the time domain of the surface multiples, g is the vector representation in the time domain of the Green’s function, and d is the time domain of the input data vector representation of .
进一步的,在本发明的基于加速线性Bregman算法的表面多次波和子波估计系统中,若待估计的格林函数已经达到最大更新次数而待估计的震源子波未达到最大更新次数,则再次进行步骤S11时,lmax被更新为待估计的震源子波的最大更新次数减去已经更新的次数后的差值,且之前每次执行步骤S11时的lmax相等;若待估计的震源子波已经达到最大更新次数而待估计的格林函数未达到最大更新次数,则后续只进行一次步骤S12,且每次执行步骤S11时的lmax相等。Further, in the surface multiple wave and wavelet estimation system based on the accelerated linear Bregman algorithm of the present invention, if the Green's function to be estimated has reached the maximum number of updates and the source wavelet to be estimated has not reached the maximum number of updates, then carry out again. In step S11, lmax is updated to the difference between the maximum update times of the source wavelet to be estimated minus the number of times that have been updated, and the lmax when step S11 is executed before each time is equal; if the source wavelet to be estimated If the maximum number of updates has been reached but the Green's function to be estimated has not reached the maximum number of updates, then step S12 is performed only once, and lmax is the same each time step S11 is performed.
实施本发明的基于加速线性Bregman算法的估计方法及系统中,具有以下有益效果:本发明的估计方法及系统可估计出随炮集空间位置变化的震源子波,且估计方法及系统的效率高、耗时少、估计出结果的精度高。The estimation method and system based on the accelerated linear Bregman algorithm of the present invention have the following beneficial effects: the estimation method and system of the present invention can estimate the source wavelet that varies with the spatial position of the shot collection, and the estimation method and system have high efficiency , less time-consuming, and high accuracy of the estimated results.
附图说明Description of drawings
下面将结合附图及实施例对本发明作进一步说明,附图中:The present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:
图1是本发明的加速线性Bregman算法求解Ax=b以得到稀疏解x一优选实施例的流程图;1 is a flowchart of a preferred embodiment of the accelerated linear Bregman algorithm of the present invention to solve Ax=b to obtain a sparse solution x;
图2是本发明的估计方法的估计震源子波和表面多次波一优选实施例的流程图;2 is a flowchart of a preferred embodiment of the estimation method of the present invention for estimating source wavelets and surface multiples;
图3是真解、部分算法求出的解以及求出的解与真解之间误差的示意图;3 is a schematic diagram of the true solution, the solution obtained by some algorithms, and the error between the obtained solution and the true solution;
图4是部分算法求出的数据残差随迭代次数的变化曲线的对比图;Figure 4 is a comparison diagram of the variation curve of the data residual obtained by some algorithms with the number of iterations;
图5(a)输入的包含多次波的数据示意图;Figure 5(a) is a schematic diagram of the input data including multiples;
图5(b)为本发明估计的一次波数据示意图;Figure 5(b) is a schematic diagram of primary wave data estimated by the present invention;
图5(c)为本发明估计的表面多次波数据示意图;Figure 5(c) is a schematic diagram of surface multiple data estimated by the present invention;
图6(a)为图5(a)中数据的零炮检剖面示意图;Figure 6(a) is a schematic diagram of the zero-offset cross-section of the data in Figure 5(a);
图6(b)为本发明估计的表面多次波数据示意图;Figure 6(b) is a schematic diagram of surface multiple data estimated by the present invention;
图6(c)为本发明一实施例估计的一次波数据示意图;FIG. 6(c) is a schematic diagram of primary wave data estimated by an embodiment of the present invention;
图6(d)为Lin和Herrmann的REPSI方法估计的一次波数据示意图;Figure 6(d) is a schematic diagram of the primary wave data estimated by Lin and Herrmann's REPSI method;
图7(a)为估计的震源子波的示意图;Figure 7(a) is a schematic diagram of the estimated source wavelet;
图7(b)为本发明一实施例估计的随炮集变化的震源子波的频率域振幅谱示意图;Fig. 7(b) is a schematic diagram of the frequency domain amplitude spectrum of the source wavelet estimated with the shot collection according to an embodiment of the present invention;
图8为Lin和Herrmann的REPSI方法、原始线性Bregman算法、加速线性Bregman算法的反演误差随迭代次数的变化曲线图Fig. 8 is a graph showing the inversion error of Lin and Herrmann's REPSI method, the original linear Bregman algorithm, and the accelerated linear Bregman algorithm with the number of iterations
图9(a)为国际SMAART JV组织公开释放的用于测试多次波压制方法的Pluto 1.5数据示意图;Figure 9(a) is a schematic diagram of the Pluto 1.5 data released by the international SMAART JV organization for testing the multiple-wave suppression method;
图9(b)为本发明估计的一次波数据示意图;Figure 9(b) is a schematic diagram of primary wave data estimated by the present invention;
图9(c)为本发明估计的表面相关多次波数据示意图;Figure 9(c) is a schematic diagram of surface-related multiple data estimated by the present invention;
图10(a)为图9(a)中数据的零炮检剖面示意图;Fig. 10(a) is a schematic diagram of the zero-offset cross-section of the data in Fig. 9(a);
图10(b)为本发明估计的一次波数据示意图;Figure 10(b) is a schematic diagram of primary wave data estimated by the present invention;
图10(c)本发明估计的表面相关多次波数据示意图;Figure 10(c) is a schematic diagram of surface-related multiple data estimated by the present invention;
图11(a)为从Pluto 1.5数据中估计的随炮集变化的震源子波示意图;Figure 11(a) is a schematic diagram of the source wavelet estimated from the Pluto 1.5 data as a function of shot collection;
图11(b)为从Pluto 1.5数据中估计的随炮集变化的震源子波的频率域振幅谱示意图;Figure 11(b) is a schematic diagram of the frequency domain amplitude spectrum of the source wavelet estimated from the Pluto 1.5 data as a function of shot collection;
图12(a)为图9(a)中数据的中间炮的数据剖面示意图;Fig. 12 (a) is the data section schematic diagram of the middle gun of the data in Fig. 9 (a);
图12(b)为本发明估计的一次波数据示意图;Figure 12(b) is a schematic diagram of primary wave data estimated by the present invention;
图12(c)为本发明估计的一阶表面多次波数据示意图;Fig. 12(c) is a schematic diagram of first-order surface multiple data estimated by the present invention;
图12(d)为本发明估计的二阶表面多次波数据示意图;Figure 12(d) is a schematic diagram of second-order surface multiple data estimated by the present invention;
图12(e)为本发明估计的三阶表面多次波数据示意图;Figure 12(e) is a schematic diagram of third-order surface multiple data estimated by the present invention;
图12(f)为本发明估计的四阶表面多次波数据示意图;Figure 12(f) is a schematic diagram of the fourth-order surface multiple data estimated by the present invention;
图12(g)为本发明估计的五阶表面多次波数据示意图;Figure 12(g) is a schematic diagram of fifth-order surface multiple data estimated by the present invention;
图12(h)为图12(b)至图12(g)中数据的累加求和的示意图;Figure 12(h) is a schematic diagram of the accumulation and summation of the data in Figures 12(b) to 12(g);
图12(i)为图12(a)和图12(h)的差的示意图;Figure 12 (i) is a schematic diagram of the difference between Figure 12 (a) and Figure 12 (h);
图13(a)为Pluto 1.5数据中炮号介于701-880的零炮检局剖面的示意图;Figure 13(a) is a schematic diagram of the cross-section of the zero-scanning bureau with shot numbers between 701-880 in the Pluto 1.5 data;
图13(b)为本发明估计的一次波数据示意图;Figure 13(b) is a schematic diagram of primary wave data estimated by the present invention;
图13(c)为本发明估计的表面相关多次波数据示意图。Fig. 13(c) is a schematic diagram of surface-related multiple data estimated by the present invention.
名词说明noun description
一次波(Primaries):是指激发的地震波在地层传播过程中仅在地下界面发生一次反射即被埋置在地表的检波器所接收,称为一次反射波,简称一次波。本发明中所涉及的一次波是指除表面多次波之外的所有波,也即这里的一次波包含了层间多次波(其与表面无关)。Primary wave (Primaries): It means that the excited seismic wave is only reflected once at the subsurface interface during the propagation of the stratum, that is, it is received by the geophone buried on the surface, which is called the primary reflected wave, or the primary wave for short. The primary waves involved in the present invention refer to all waves except the surface multiples, that is, the primary waves here include the interlayer multiples (which have nothing to do with the surface).
多次波(Multiples):是指激发的地震波在传播过程中在地下界面或自由表面(空气与水的接触面)发生多次反射后才被埋置在地表的检波器所接收,称为多次反射波,简称多次波。Multiples: It means that the excited seismic waves are received by the geophone buried on the surface after multiple reflections on the underground interface or free surface (contact surface between air and water) during the propagation process. Secondary reflected waves, referred to as multiple waves.
表面相关多次波(Surface-related multiples)或表面多次波(Surfacemultiples):是指与自由表面(空气与水的接触面)相关的多次反射波,在本发明中简述为表面多次波。Surface-related multiples (Surface-related multiples) or surface multiples (Surfacemultiples): refers to the multiple reflection waves related to the free surface (air and water contact surface), which are briefly described as surface multiples in the present invention Wave.
层间多次波(Internal multiples,IM):是指在地下反射界面之间(地层之间)产生的多次反射波。Interlayer multiples (Internal multiples, IM): refers to the multiple reflection waves generated between the subsurface reflection interfaces (between formations).
震源子波:指的是震源激发产生的波。Source wavelet: refers to the wave generated by the source excitation.
Feedback model:反馈模型。Feedback model: Feedback model.
Surface-Related Multiple Elimination(SRME):表面相关多次波压制。Surface-Related Multiple Elimination (SRME): Surface-Related Multiple Elimination.
Estimation of Primaries by Sparse Inversion(EPSI):稀疏反演一次波估计。Estimation of Primaries by Sparse Inversion (EPSI): Sparse primary wave estimation for inversion.
Robust Estimation of Primaries by Sparse Inversion(EPSI):稳健的稀疏反演一次波估计。Robust Estimation of Primaries by Sparse Inversion (EPSI): Robust sparse inversion primary wave estimation.
:Spectral-Projected 谱映射梯度一范数算法。 : Spectral-Projected Gradient-norm algorithm for spectral mapping.
LSQR:Least-squares QR,最小二乘QR分解算法。LSQR: Least-squares QR, least squares QR decomposition algorithm.
Linearized Bregman(LB):线性Bregman算法。Linearized Bregman (LB): Linearized Bregman algorithm.
Accelerated Linearized Bregman(ALB):加速线性Bregman算法。Accelerated Linearized Bregman (ALB): Accelerated Linearized Bregman algorithm.
MATLAB:是美国MathWorks公司出品的商业数学软件,用于算法开发、数据可视化、数据分析以及数值计算的高级技术计算语言和交互式环境。MATLAB是matrix&laboratory两个词的组合,意为矩阵工厂(矩阵实验室)。MATLAB: It is a commercial mathematical software produced by MathWorks in the United States. It is a high-level technical computing language and interactive environment for algorithm development, data visualization, data analysis, and numerical computing. MATLAB is a combination of the words matrix&laboratory, which means matrix factory (matrix laboratory).
Signal-to-Noise Ratios(SNR):信噪比。Signal-to-Noise Ratios (SNR): Signal-to-Noise Ratio.
具体实施方式Detailed ways
为了对本发明的技术特征、目的和效果有更加清楚的理解,现对照附图详细说明本发明的具体实施方式。为了方便对本发明的理解,现对上述以及下述各表达式字母作如下说明,小写的字母s、g、d、p、m为表示时间域的向量表达形式,S、G、D、P、M为时间域的矩阵表达形式。为S、G、D、P、M的频率域的矩阵表达形式的切片,上标est表示待估计,为s、g、d、p、m的频率域的向量表达形式,S、G、D、P、M为三维矩阵,而其切片则为二维矩阵,每一个三维矩阵可以拆分为多个二维矩阵。任何一个二维矩阵Z=[Z1Z2Z3…Zn]的向量表达形式可以表达为:In order to have a clearer understanding of the technical features, objects and effects of the present invention, the specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the present invention, the above and the following expression letters are now described as follows, the lowercase letters s, g, d, p, m are the vector expressions representing the time domain, S, G, D, P, M is the matrix representation in the time domain. is a slice of the matrix representation of the frequency domain of S, G, D, P, and M, and the superscript est indicates to be estimated, It is the vector expression form of the frequency domain of s, g, d, p, and m. S, G, D, P, and M are three-dimensional matrices, and their slices are two-dimensional matrices. Each three-dimensional matrix can be divided into multiple 2D matrix. The vector representation of any two-dimensional matrix Z=[Z 1 Z 2 Z 3 ... Z n ] can be expressed as:
其中Z1至Zn表示二维矩阵Z的列,反之,由向量表达形式可以得矩阵表达形式。 Among them, Z 1 to Z n represent the columns of the two-dimensional matrix Z. On the contrary, the matrix expression form can be obtained from the vector expression form.
一次波、表面多次波和震源子波估计利用的主要公式是反馈模型的数学物理关系式,也即公式(1)。激发的震源子波s传入地下,同地下脉冲响应格林函数g进行时域褶积(星号*表示褶积),产生一次波p,数学关系表达式为:The main formula used in the estimation of primary waves, surface multiples and source wavelets is the mathematical-physical relational formula of the feedback model, that is, formula (1). The excited source wavelet s is introduced into the subsurface and undergoes time domain convolution with the subsurface impulse response Green's function g (asterisk * indicates convolution) to generate a primary wave p. The mathematical relationship is expressed as:
p=g*s (2)p=g*s (2)
产生的一次波p遇到海水与空气接触面发生反射,向下传播,进而作为震源再次传入地下,同地下脉冲响应g进行时域褶积,产生一阶多次波m1 The generated primary wave p is reflected at the contact surface between seawater and air, propagates downward, and then re-introduces into the ground as a seismic source, where it undergoes time-domain convolution with the underground impulse response g to generate first-order multiple waves m 1
m1=g*rsurfp=rsurfg*g*s (3)m 1 =g*r surf p=r surf g*g*s (3)
产生的一阶多次波m1遇到自由表面发生反射,进而作为震源再次传入地下,同地下脉冲响应g进行时域褶积,产生二阶多次波m2 The generated first-order multiples m 1 are reflected from the free surface, and then re-introduced into the ground as the source, where they are convolved with the subsurface impulse response g in the time domain to generate second-order multiples m 2
m2=g*rsurfm1=(rsurf)2g*g*g*s (4)m 2 =g*r surf m 1 =(r surf ) 2 g*g*g*s (4)
更高阶次的表面相关多次波产生公式以此类推。The higher-order surface-related multiple generation formulas are analogous.
观测得到的总的数据d为一次波p和所有阶次表面相关多次波的总和,其数学表达式为:The total observed data d is the sum of the primary wave p and the surface-related multiples of all orders, and its mathematical expression is:
进而有and then have
上述反馈模型数学物理关系表达式可总结为:The mathematical-physical relationship expression of the above feedback model can be summarized as:
表达式(1)即为表达式7在二维或三维情况下的频率域矩阵表达形式,对于公式7中的参数均修改为其对应的频率域的矩阵表达形式也成立,为便于对比,将其转写于此:Expression (1) is the frequency domain matrix expression form of Expression 7 in the case of two-dimensional or three-dimensional, and the parameters in formula 7 are modified to the corresponding matrix expression form in the frequency domain. It is transcribed here:
本发明的主要目的是:根据表达式7-8,求解未知变量:震源子波s和格林函数g,进而得到估计的一次波p=g*s和表面多次波m=rsurfg*d。The main purpose of the present invention is: according to expressions 7-8, solve the unknown variables: the source wavelet s and the Green's function g, and then obtain the estimated primary wave p=g*s and surface multiples m=r surf g*d .
本发明首先说明给定估计的震源子波情况下,反演稀疏脉冲响应格林函数的方法。The present invention first describes a method for inverting a Green's function of a sparse impulse response given an estimated source wavelet.
在给定估计的震源子波sest的情况下,根据表达式(7)-(8),我们写出反演gest时所用的公式,也即:Given the estimated source wavelet s est , according to expressions (7)-(8), we write the formula used for inversion g est , namely:
这里是一个简化代表性的正演算子,其核心是在计算公式8中的具体的,矩阵算子表示进行下述操作的操作集合:将待估计的格林函数由时间域的向量表形式g进行傅里叶变换变为频率域的向量表形式将待估计的格林函数由频率域的向量表形式变为频率域的矩阵表形式根据公式分别计算输入数据对应的模拟数据的频率域的矩阵表达形式的各个切片根据计算出的输入数据对应的模拟数据的频率域的矩阵表达形式的各个切片进行反傅里叶变换得到输入数据对应的模拟数据的时间域的向量表达形式 here is a simplified and representative forward calculus operator, the core of which is in the calculation formula 8 Specifically, the matrix operator Represents a set of operations that perform the following operations: Fourier transform the Green's function to be estimated from the vector table form g in the time domain into a vector table form in the frequency domain Convert the Green's function to be estimated in the form of a vector table in the frequency domain into a matrix table form in the frequency domain According to the formula Calculate each slice of the matrix representation of the frequency domain of the analog data corresponding to the input data separately Each slice of the matrix representation of the frequency domain of the analog data corresponding to the calculated input data Perform the inverse Fourier transform to obtain the vector representation in the time domain of the analog data corresponding to the input data
为了便于进一步阐述本发明怎么求解得到稀疏格林函数g,将9式改写为下面的标准形式:In order to further explain how the present invention solves and obtains the sparse Green's function g, formula 9 is rewritten into the following standard form:
Ax=b (10)Ax=b (10)
其中,x=g,b=d。in, x=g, b=d.
为了寻求格林函数g的稀疏解,本发明利用加速线性Bregman算法求解10式。加速线性Bregman算法旨在求解:In order to seek the sparse solution of the Green's function g, the present invention uses the accelerated linear Bregman algorithm to solve Equation 10. The accelerated linear Bregman algorithm is designed to solve:
表示求解出x使得表达式取得最小值,subject to表示在限定条件下。 Indicates that x is solved so that the expression achieves the minimum value, and subject to is under limited conditions.
其中,μ≥0为稀疏度控制因子,||x||1和||x||2分别代表向量的范数和范数,σ代表数据中的噪声水平因子。下面的算法1给出了加速线性Bregman算法的详细迭代步骤。Among them, μ≥0 is the sparsity control factor, ||x|| 1 and ||x|| 2 represent the vector norm sum norm, σ represents the noise level factor in the data. Algorithm 1 below gives the detailed iterative steps to speed up the linear Bregman algorithm.
参考图1,图1是本发明的加速线性Bregman算法求解Ax=b以得到稀疏解x的流程图,也即算法1的流程图,算法1具体的包含下述步骤:Referring to FIG. 1, FIG. 1 is a flowchart of the accelerated linear Bregman algorithm of the present invention to solve Ax=b to obtain a sparse solution x, that is, a flowchart of Algorithm 1, and Algorithm 1 specifically includes the following steps:
a)获取下述参数:正演算子A,观测数据向量b,初始值向量x0,阈值μ,最大迭代次数lmax。a) Obtain the following parameters: forward operator A, observation data vector b, initial value vector x 0 , threshold μ, maximum number of iterations l max .
b)初始化:迭代变量l=0,将x0赋值给y0 b) Initialization: iterative variable l=0, assign x 0 to y 0
c)重复进行下述各d至g步骤lmax次c) Repeat steps d to g below for 1 max times
d)计算 d) Calculate
e)计算 e) calculation
f)计算 f) calculation
g)将l更新为l+1g) update l to l+1
h)得出稀疏解该稀疏解x即为本次进行加速线性Bregman算法的更新gest后结果。h) get a sparse solution The sparse solution x is the result after the update of the accelerated linear Bregman algorithm this time.
在上述算法1中,步骤d的tl代表的是步长,其表达式为:In the above algorithm 1, t l of step d represents the step size, and its expression is:
其中,上标H代表复共轭转置。映射函数∏σ(Axl-b)是为考虑数据中存在的噪声,其定义为:where the superscript H stands for complex conjugate transpose. The mapping function ∏ σ (Ax l -b) is to consider the noise existing in the data, which is defined as:
而软阈值函数shrink(x,μ)定义为:The soft threshold function shrink(x, μ) is defined as:
shrink(x,μ)=max(|x|-μ,0)sign(x) (14)shrink(x,μ)=max(|x|-μ,0)sign(x) (14)
其中,max(·)函数表示取最大值,|·|函数表示取绝对值,sign(x)表示符号取值函数。Among them, the max(·) function represents the maximum value, the |·| function represents the absolute value, and the sign(x) represents the sign value function.
在上述算法1中,αl的定义表达式为:In the above Algorithm 1, the definition expression of α l is:
本方法通过加权系统αl来加速算法的收敛速率。This method accelerates the convergence rate of the algorithm by weighting the system α l .
本发明下述将说明在反演得到稀疏脉冲响应格林函数的情况下,估计震源子波。The following description of the present invention will describe the estimation of the source wavelet under the condition that the Green's function of the sparse impulse response is obtained by inversion.
当反演得到gest后,根据公式8,我们估计震源子波时要解决的问题为:When g est is obtained by inversion, according to Equation 8, the problem to be solved when estimating the source wavelet is:
此时为待求解的未知数。我们用一个简单的推导来阐释本发明进行震源子波估计的方案。估计震源子波,即要估计震源子波频率域的傅里叶频谱。假定两个复值向量a和b满足下面的关系:at this time is the unknown to be solved. We illustrate the scheme of the present invention for source wavelet estimation with a simple derivation. To estimate the source wavelet, that is, to estimate the Fourier spectrum of the source wavelet in the frequency domain. Suppose two complex-valued vectors a and b satisfy the following relationship:
ac=b (17)ac=b (17)
其中c为待求的震源子波傅里叶变换谱复系数。进而我们有:where c is the complex spectral coefficient of the Fourier transform of the source wavelet to be obtained. Then we have:
aHac=aHb (18)a H ac = a H b (18)
进而得到,to get,
本发明即根据上面的推导来估计随炮集空间位置变化的震源子波。根据公式16和公式19,当估计的震源子波不随炮集空间位置变化时(也即常子波估计),有:According to the above derivation, the present invention estimates the source wavelet which changes with the spatial position of the shot collection. According to Equation 16 and Equation 19, when the estimated source wavelet does not change with the spatial position of the shot collection (that is, constant wavelet estimation), there are:
当估计的震源子波随炮集空间位置变化时(也即变子波估计),有:When the estimated source wavelet changes with the spatial position of the shot collection (that is, the variable wavelet estimation), there are:
其中,S(j,j)代表震源子波矩阵对角线上的元素,j表示随炮集空间位置或炮集编号变化,vec(·)表示将一个矩阵变为列向量,H代表复共轭转置,下标代表取一个频率切片矩阵的第j列,下标代表取一个频率切片矩阵的所有列。在进行震源子波估计时,本发明不需要任何假设条件,也即不需要对子波的相位做任何假设。另外,相比于传统不考虑多次波的子波估计问题,本发明进行子波估计时的多次波项有助于克服传统子波估计存在的(振幅和相位)非唯一性问题。Among them, S (j, j) represents the element on the diagonal of the source wavelet matrix, j represents the change with the spatial position of the shot set or the shot set number, vec( ) represents the transformation of a matrix into a column vector, and H represents the complex common yoke transpose, subscript Represents taking the jth column of a frequency slice matrix, subscript Represents taking all columns of a frequency slice matrix. When estimating the source wavelet, the present invention does not require any assumptions, that is, it does not need to make any assumptions about the phase of the wavelet. In addition, compared with the traditional wavelet estimation problem that does not consider multiples, the multiple-wave term in the present invention helps to overcome the (amplitude and phase) non-uniqueness problems existing in the traditional wavelet estimation.
图2是本发明的估计方法的一优选实施例的流程图,该估计方法包括如下步骤:FIG. 2 is a flowchart of a preferred embodiment of the estimation method of the present invention, and the estimation method includes the following steps:
a)获取下述数据:数据d,阈值μ,gest的最大迭代更新次数kmax,加速线性Bregman算法内部迭代次数lmax,sest的最大迭代更新次数mmax。a) Obtain the following data: data d, threshold μ, maximum iteration update times k max of g est , internal iteration times l max of the accelerated linear Bregman algorithm, and maximum iteration update times m max of s est .
b)初始化:迭代变量k=0,m=0,b=d,gest及sest初始化为0。b) Initialization: the iteration variables k=0, m=0, b=d, gest and sest are initialized to 0.
c)判断k<kmax是否成立,若成立,则重复执行步骤c-i,否则执行步骤j。c) Determine whether k<k max is established, if so, repeat step ci, otherwise execute step j.
d)根据x0=gest、sest以及b=d,调用算法1来更新得到gest。d) According to x 0 =g est , s est and b=d, call Algorithm 1 to update to obtain g est .
e)将k更新为k+lmax。e) Update k to k+l max .
f)判断m<mmax是否成立,若成立,则执行步骤g-i。f) Determine whether m<m max is established, if so, execute step gi.
g)根据b及更新后的gest,调用公式20或21式来更新得到sest。通过公式20或21算出每一个对角矩阵中的对角线上每一个元素,根据计算出的所有的更新sest。g) According to b and the updated g est , call formula 20 or 21 to update to obtain s est . Calculate each diagonal matrix by Equation 20 or 21 For each element on the diagonal in , according to the calculation of all Update s est .
h)判断m=mmax-1是否成立,若成立则将kmax-k赋值给lmax。h) Determine whether m=m max -1 is established, and if so, assign k max -k to l max .
i)将m+1赋值给m。i) Assign m+1 to m.
j)根据最终更新后的结果,得出震源子波以及表面多次波的估计结果。j) According to the final updated results, the estimation results of source wavelets and surface multiples are obtained.
上述过程中有两个未知数:震源子波的切片sest和格林函数的切片gest,在求解反问题流程上类似于传统的盲反褶积方法,即固定sest,来反演gest;接着固定gest,来估计sest。在反演gest时,每次迭代更新都用到了前一次的反演结果。在反演稀疏gest解时,往往需要迭代几次,因为根据稀疏恢复理论,往往需要迭代几次才能收敛得到一个最优稀疏解。在得到一个稀疏解gest后,再进行震源子波估计。估计得到的sest即刻用于反演更新gest。整个迭代主循环在满足某个停止准则后退出结束。交替更新gest与sest的预设次数决定于kmax、以及mmax,当gest达到最大更新次数后kmax而sest没有达到最大更新次数时,在执行gest的最后一次更新后,执行一次sest的更新即完成了gest与sest的交替更新,其中每次进行加速线性Bregman算法的lmax相等;当sest达到最大更新次数后kmax而gest没有达到最大更新次数时,在执行sest的最后一次更新后,只执行最后一次加速线性Bregman算法,最后一次执行加速线性Bregman算法的lmax被赋值为gest的最大更新次数与已经更新的次数的差值,而之前的每次执行加速线性Bregman算法的lmax相等。其中每次进行加速线性Bregman算法的lmax相等最后一次更新gest即g的估计结果,最后一次更新sest即为s的估计结果,下述采用gest表示g的估计结果,sest表示s的估计结果。There are two unknowns in the above process: the slice s est of the source wavelet and the slice g est of the Green's function. The process of solving the inverse problem is similar to the traditional blind deconvolution method, that is, fixing s est to invert g est ; Then fix g est to estimate s est . When inverting g est , each iteration update uses the previous inversion results. When inverting the sparse gest solution, it often needs several iterations, because according to the sparse recovery theory, it often takes several iterations to converge to obtain an optimal sparse solution. After a sparse solution g est is obtained, the source wavelet estimation is performed. The estimated s est is immediately used for inversion to update g est . The entire iterative main loop exits after satisfying a certain stopping criterion. The preset times of alternately updating g est and s est are determined by k max and m max . When g est reaches the maximum number of updates and k max but s est does not reach the maximum number of updates, after the last update of g est is performed, Executing the update of s est once completes the alternate update of g est and s est , in which the l max of the accelerated linear Bregman algorithm is equal each time; when s est reaches the maximum number of updates, k max and g est does not reach the maximum number of updates , after the last update of s est , only the last accelerated linear Bregman algorithm is executed, and the l max of the last accelerated linear Bregman algorithm is assigned as the difference between the maximum number of updates of g est and the number of times that have been updated, and before The lmax of each execution of the accelerated linear Bregman algorithm is equal. Among them, the lmax of the accelerated linear Bregman algorithm is equal each time. The last update g est is the estimated result of g, and the last update of s est is the estimated result of s. The following uses g est to represent the estimated result of g, and s est to represent s estimated results.
在得到gest和sest后,计算获得一次波p=gest*sest。After the g est and s est are obtained, the primary wave p=g est *s est is obtained by calculation.
由gest和输入数据获得表面相关多次波m=rsurfgest*d。by g est and input data Obtain surface correlated multiples m=r surf g est *d.
根据二次震源原理,在得到格林函数gest和获得的一次波p后,由反馈迭代模型计算得到不同阶次的表面相关多次波时域的切片,比如,一阶表面多次波m1的计算公式为:According to the principle of the secondary source, after obtaining the Green function g est and the obtained primary wave p, the time domain slices of the surface-related multiples of different orders are calculated by the feedback iterative model, for example, the first-order surface multiples m 1 The calculation formula is:
m1=rsurfgest*p=rsurfgest*gest*uest (22)m 1 =r surf g est *p=r surf g est *g est *u est (22)
二阶表面多次波的时域的切片m2的计算公式为:The formula for calculating the slice m2 in the time domain of the second-order surface multiple is:
m2=rsurfgest*m1=(rsurf)2gest*gest*gest*sest (23)m 2 =r surf g est *m 1 =(r surf ) 2 g est *g est *g est *s est (23)
其它阶次的表面相关多次波的计算公式以此类推。The calculation formulas of surface-related multiples of other orders are analogous.
由于多次波估计时的计算量大部分耗在每个频率切片在做矩阵-矩阵乘积,也即计算8式,所以为了进一步减少多次波估计的运算耗时,本发明根据地震数据的带限特性(也即地震数据的频率成分主要集中在某一有限长度的频带范围内),本发明在多次波、震源子波估计时仅利用了地震数据可信度和信噪比高的优势频带,大大减少了方法的计算耗时,这不同于传统方法利用了所有的(包括可信度和信噪比低的)频率成分。Since most of the calculation amount in multiple wave estimation is spent in each frequency slice doing matrix-matrix product, that is, calculating Equation 8, in order to further reduce the computational time consuming of multiple wave estimation, the present invention uses seismic data according to the (that is, the frequency components of seismic data are mainly concentrated in a frequency band of a limited length), the present invention only utilizes the advantages of high reliability and high signal-to-noise ratio of seismic data when estimating multiples and source wavelets frequency bands, which greatly reduces the computational time of the method, which is different from the traditional method which utilizes all (including low reliability and signal-to-noise ratio) frequency components.
在求出一次波或者表面多次波后,就可以利用它们分别得出地下结构图。After the primary wave or the surface multiple waves are obtained, the underground structure map can be obtained by using them respectively.
我们这里给出了以下几个具体实例来说明本发明技术方案的可行性、有效性和优越性。We provide the following specific examples to illustrate the feasibility, effectiveness and superiority of the technical solution of the present invention.
(1)稀疏恢复数值例子,以说明本发明加速线性Bregman算法的优越性。(1) Numerical example of sparse restoration to illustrate the superiority of the accelerated linear Bregman algorithm of the present invention.
(2)盐丘模型数据例子。该数据由荷兰代尔夫特理工大学的DELPHI多次波研究小组所模拟生成,是国际上用于公开测试多次波算法的标志性数据之一。其曾在vanGroenestijn和Verschuur的2009年论文、Lin和Herrmann的2013年论文中出现并用于多次波估计方法的测试。(2) Example of salt dome model data. The data was simulated and generated by the DELPHI multiples research group at Delft University of Technology in the Netherlands, and it is one of the landmark data used for public testing of multiples algorithms in the world. It has appeared in van Groenestijn and Verschuur's 2009 paper, and Lin and Herrmann's 2013 paper and used to test multiple estimation methods.
(3)Pluto 1.5数据例子。该数据由国际上Subsalt Multiples Attenuation andReduction Team Joint Venture(SMAART JV)组织模拟生成并公开释放,也是国际上用于公开测试多次波算法的标志性数据之一。(3) Pluto 1.5 data example. This data is simulated and released by the international Subsalt Multiples Attenuation and Reduction Team Joint Venture (SMAART JV) organization, and it is also one of the landmark data used for public testing of multiple wave algorithms in the world.
稀疏恢复数值例子Numerical example of sparse recovery
本数值例子中的真实模型和模拟的数据均为随机产生。我们首先随机产生了一个稀疏向量,其长度为512,在512个点中有30个非零值。对于512个未知数,我们随机产生了450个观测数据,也即:对512个未知数,建立了450个方程组,此方程组系统是欠定的,因为方程个数小于未知数个数。对于所有参与对比的方法,我们设定最大迭代次数为20。由于模拟数据不含噪声,可以隔离噪声对所有算法的影响。对算法我们采用了其开发者所推荐默认的参数。这里我们用信噪比SNR和运行时间来评价参与对比的算法,其中信噪比的计算公式为:The real model and simulated data in this numerical example are generated randomly. We first randomly generated a sparse vector of length 512 with 30 non-zero values in 512 points. For the 512 unknowns, we randomly generated 450 observational data, that is, for the 512 unknowns, 450 equations were established. This system of equations is underdetermined because the number of equations is less than the number of unknowns. For all participating methods, we set the maximum number of iterations to 20. Since the simulated data is noise free, the effects of noise on all algorithms can be isolated. right For the algorithm, we adopted the default parameters recommended by its developers. Here we use the signal-to-noise ratio (SNR) and the running time to evaluate the algorithms involved in the comparison. The calculation formula of the signal-to-noise ratio is:
这里x代表真实解,代表求得的解。Here x represents the true solution, represents the solution obtained.
从图3(第一行代表的是真实的稀疏模型,也即真解;第二行代表的是由最小二乘QR分解法求解得到的结果;第三行代表的是由算法求解得到的结果;第四行代表的是算法求解得到的结果同真实解的误差;第五行代表的是线性Bregman算法求解得到的结果;第六行代表的是本发明加速线性Bregman算法求解得到的结果;第七行代表的是本发明加速线性Bregman算法求解得到的结果同真实解的误差)中我们可以看出最小二乘QR分解算法求得的解存在很多随机噪声。算法求得解的精度远不如线性Bregman算法和本发明加速线性Bregman算法。算法求得解的误差要比本发明加速线性Bregman算法的误差大很多。本发明加速线性Bregman算法求得的解具有最高的信噪比SNR。图3同时表明了本发明加速线性Bregman算法的运行时间要比算法的运行时间少很多(约减少了90%)。From Figure 3 (the first row represents the real sparse model, that is, the true solution; the second row represents the result obtained by the least squares QR decomposition method; the third row represents the The result obtained by the algorithm solution; the fourth row represents the The error between the result obtained by the algorithm and the real solution; the fifth row represents the result obtained by the linear Bregman algorithm; the sixth row represents the result obtained by the accelerated linear Bregman algorithm of the present invention; the seventh row represents the acceleration of the present invention From the error between the result obtained by the linear Bregman algorithm and the real solution), we can see that there is a lot of random noise in the solution obtained by the least squares QR decomposition algorithm. The accuracy of the solution obtained by the algorithm is far inferior to that of the linear Bregman algorithm and the accelerated linear Bregman algorithm of the present invention. The error of the solution obtained by the algorithm is much larger than that of the accelerated linear Bregman algorithm of the present invention. The solution obtained by the accelerated linear Bregman algorithm of the present invention has the highest signal-to-noise ratio SNR. Fig. 3 also shows that the running time of the accelerated linear Bregman algorithm of the present invention is higher than The running time of the algorithm is much less (about 90% reduction).
从图4中(黑色细实线代表的是最小二乘QR分解算法的数据残差随迭代次数的变化曲线;黑色细虚线代表的是算法的数据残差随迭代次数的变化曲线;黑色粗虚线代表的是线性Bregman算法的数据残差随迭代次数的变化曲线;黑色粗实线代表的是本发明加速线性Bregman算法的数据残差随迭代次数的变化曲线)展示的求解过程中数据匹配误差随迭代次数的变化趋势来看,线性Bregman算法的收敛速度要优于最小二乘QR分解算法和算法。而本发明加速线性Bregman算法的收敛速度要进一步优于线性Bregman算法。From Figure 4 (the black thin solid line represents the change curve of the data residual of the least squares QR decomposition algorithm with the number of iterations; the black thin dashed line represents the The change curve of the data residual of the algorithm with the number of iterations; the black thick dashed line represents the change curve of the data residual of the linear Bregman algorithm with the number of iterations; the black thick solid line represents the data residual of the accelerated linear Bregman algorithm of the present invention. The variation curve of the number of iterations) shows that the data matching error changes with the number of iterations in the solution process, the convergence speed of the linear Bregman algorithm is better than that of the least squares QR decomposition algorithm and algorithm. However, the convergence speed of the accelerated linear Bregman algorithm of the present invention is further superior to that of the linear Bregman algorithm.
图3和图4中的数值实例证实了本发明中加速线性Bregman算法的有效性和优越性,即算法简单、收敛速率高。The numerical examples in Fig. 3 and Fig. 4 demonstrate the effectiveness and superiority of the accelerated linear Bregman algorithm in the present invention, that is, the algorithm is simple and the convergence rate is high.
盐丘模型数据例子Salt Dome Model Data Example
荷兰代尔夫特理工大学的DELPHI多次波研究小组模拟生成的数据见图5a,该数据由速度模型和密度模型为输入,采用有限差分正演模拟,时间采样间隔是4ms。正演模拟时所用的震源子波是Ricker子波,每炮子波一样,也即常子波。模型的浅层为约200米深的水层。为了同Lin和Herrmann的REPSI方法做对比,在处理过程中设定总的迭代次数为71。REPSI方法的结果由Lin和Herrmann所提供。本发明在处理时所用的频带范围为0-70Hz(原始整个频带范围为0-125Hz)。Figure 5a shows the data generated by the DELPHI multiple wave research group at Delft University of Technology in the Netherlands. The data is input by the velocity model and the density model, and is simulated by finite difference forward modeling with a time sampling interval of 4ms. The source wavelet used in the forward modeling is the Ricker wavelet, which is the same for every shot, that is, the constant wavelet. The shallow layer of the model is about 200 meters deep in water. In order to compare with Lin and Herrmann's REPSI method, the total number of iterations is set to 71 during processing. The results of the REPSI method are provided by Lin and Herrmann. The frequency band range used in the present invention is 0-70 Hz (the original whole frequency band range is 0-125 Hz).
从图5到图6中本发明处理结果来看,本发明得到了较好的效果。在原始输入数据图6a中,多次波同一次波混杂在一起、相互干扰、分辨不清。经本发明方法处理后,多次波和一次波得以精确地分离。在图6a原始数据中属于断层的弱同相轴很难识别,经本发明处理后,在图6c中得以清晰识别、显现。由于本发明旨在处理与表面相关的多次波,进而层间多次波会被包含在处理后得到的一次波中,见图6c。From the processing results of the present invention in FIGS. 5 to 6 , the present invention has obtained better effects. In the original input data in Figure 6a, the multiple waves and the primary waves are mixed together, interfere with each other, and cannot be distinguished clearly. After being processed by the method of the present invention, the multiples and the primary are precisely separated. In the original data of Fig. 6a, the weak event axis belonging to the fault is difficult to identify, but after being processed by the present invention, it can be clearly identified and displayed in Fig. 6c. Since the present invention aims to deal with the multiples related to the surface, the interlayer multiples will be included in the primary wave obtained after processing, see Fig. 6c.
通过对比本发明结果(图6c)、Lin和Herrmann的REPSI方法结果(图6d),不难发现,本发明处理得到的一次波更加精确,多次波得以较好的估计、压制;而Lin和Herrmann的REPSI方法结果(图6d)中仍可看到一些多次波同相轴,见图6d箭头所示。By comparing the results of the present invention (Fig. 6c) and the results of the REPSI method of Lin and Herrmann (Fig. 6d), it is not difficult to find that the primary wave processed by the present invention is more accurate, and the multiple waves can be better estimated and suppressed; Some multiple events are still visible in Herrmann's REPSI method results (Fig. 6d), as indicated by the arrows in Fig. 6d.
对比图7a中本发明估计的震源子波、Lin和Herrmann的REPSI方法估计的结果(图7(a)中黑色实线代表的是本发明估计的震源子波,虚线代表的是Lin和Herrmann的REPSI方法估计的震源子波),可以看出两者的结果保持一致,这从侧面验证了本发明方法的正确性。由于此数据模拟生成时用的是不随炮集变化的常子波,所以本发明进行变子波估计时产生的结果较为一致,见图7b。Comparing the source wavelet estimated by the present invention in Fig. 7a, the results estimated by Lin and Herrmann's REPSI method (the black solid line in Fig. 7(a) represents the source wavelet estimated by the present invention, and the dashed line represents the source wavelet estimated by Lin and Herrmann. The source wavelet estimated by the REPSI method), it can be seen that the results of the two are consistent, which verifies the correctness of the method of the present invention from the side. Since the constant wavelet that does not change with the shot collection is used in the simulation and generation of this data, the results generated when the variable wavelet is estimated in the present invention are relatively consistent, as shown in Fig. 7b.
从图8(黑色实线代表的是Lin和Herrmann的REPSI方法的反演误差随迭代次数的变化;灰色实线代表的是采用原始线性Bregman算法时(常子波估计情况下)反演误差随迭代次数的变化;黑色虚线代表的是采用原始线性Bregman算法时(变子波估计情况下)反演误差随迭代次数的变化;灰色虚线代表的是加速线性Bregman算法时(变子波估计情况下)反演误差随迭代次数的变化)中迭代过程中数据匹配误差变化来看,本发明方法的收敛速度要快于Lin和Herrmann的REPSI方法。常子波估计时的收敛速度和变子波估计时的收敛速度基本一致。本发明加速线性Bregman算法的收敛速度要优于原始线性Bregman算法的收敛速度。From Figure 8 (the black solid line represents the inversion error of Lin and Herrmann's REPSI method with the number of iterations; the gray solid line represents the inversion error when the original linear Bregman algorithm is used (in the case of constant wavelet estimation) The change of the number of iterations; the black dotted line represents the change of the inversion error with the iteration number when the original linear Bregman algorithm is used (in the case of variable wavelet estimation); the gray dotted line represents the acceleration of the linear Bregman algorithm (in the case of variable wavelet estimation) ) The variation of inversion error with the number of iterations), the convergence speed of the method of the present invention is faster than that of the REPSI method of Lin and Herrmann from the point of view of the variation of the data matching error in the iterative process. The convergence speed of constant wavelet estimation is basically the same as that of variable wavelet estimation. The convergence speed of the accelerated linear Bregman algorithm of the present invention is better than the convergence speed of the original linear Bregman algorithm.
下表中的运行时间数据表明:在同样的计算环境和计算资源下,本发明方法的运行时间要远远小于Lin和Herrmann的REPSI方法运行时间。变子波估计时的计算耗时要比常子波估计时的计算耗时稍微多一些。本发明方法的运行时间要远远小于Lin和Herrmann的REPSI方法运行时间的主要原因如下:The running time data in the following table shows that: under the same computing environment and computing resources, the running time of the method of the present invention is far less than the running time of the REPSI method of Lin and Herrmann. The calculation time of variable wavelet estimation is slightly more than that of constant wavelet estimation. The main reason why the running time of the method of the present invention is far less than the running time of the REPSI method of Lin and Herrmann is as follows:
(1)本发明加速线性Bregman算法步骤的简单性,这同Lin和Herrmann采用的算法的复杂性形成鲜明对比;(1) The present invention accelerates the simplicity of the steps of the linear Bregman algorithm, which is the same as that adopted by Lin and Herrmann. The complexity of the algorithms contrasts sharply;
(2)本发明在进行震源子波估计时,仅需要计算公式20或21这简单高效的一步;而Lin和Herrmann的REPSI方法在进行震源子波估计时,调用最小二乘QR分解算法,需要多次迭代;(2) The present invention only needs to calculate the simple and efficient step of formula 20 or 21 when estimating the source wavelet; while the REPSI method of Lin and Herrmann calls the least squares QR decomposition algorithm when estimating the source wavelet, which requires multiple iterations;
(3)本发明根据地震数据的带限特性,在多次波、震源子波估计时仅利用了地震数据可信度和信噪比高的优势频带0-70Hz(见图6b);而Lin和Herrmann的方法用到了整个频带0-125Hz,产生了大量没有必要的计算耗时。(3) According to the band-limited characteristics of seismic data, the present invention only utilizes the dominant frequency band 0-70 Hz (see Fig. 6b), which has high reliability of seismic data and high signal-to-noise ratio, in the estimation of multiples and source wavelets (see Fig. 6b); And Herrmann's method uses the entire frequency band 0-125Hz, resulting in a lot of unnecessary computational time.
综上,我们利用同一数据、同样的计算资源环境,同Lin和Herrmann在2013年所提出REPSI方法做对比,展示了本发明的优点。In summary, we use the same data and the same computing resource environment to compare with the REPSI method proposed by Lin and Herrmann in 2013, and demonstrate the advantages of the present invention.
Pluto 1.5数据例子Pluto 1.5 data example
为了进一步展示本发明的有效性,我们将其应用于另一个具有说服力的Pluto1.5数据。此数据由国际上SMAART JV组织模拟生成并公开释放,是国际上用于公开测试多次波算法的标志性数据之一。该数据正演模拟时所用的震源子波是Ricker子波,每炮子波一样,也即常子波。时间采样间隔是8毫秒。我们直接利用了SMAART JV组织公开释放的原始数据,除切除直达波之外,并未对原始数据做任何预处理。从图6a和图7a中的原始输入数据来看,该数据中存在大量的多次波能量。在本发明处理过程中所用的频带范围为0-50Hz。To further demonstrate the effectiveness of the present invention, we apply it to another convincing Pluto1.5 data. This data is simulated and released by the international SMAART JV organization, and it is one of the landmark data used for public testing of multiple wave algorithms in the world. The source wavelet used in the forward modeling of the data is the Ricker wavelet, which is the same for each shot, that is, the constant wavelet. The time sampling interval is 8 ms. We directly used the raw data publicly released by the SMAART JV tissue, and did not do any preprocessing of the raw data except for the removal of direct waves. From the raw input data in Figures 6a and 7a, there is a large amount of multiple energy in this data. The frequency band used in the process of the present invention is 0-50 Hz.
从图9和图10中处理结果来看,在原始输入数据图9a和图10a中,多次波同一次波混杂在一起、相互干扰、分辨不清,而本发明实现了精确的一次波、多次波估计与分离(尤其是图7中箭头所指之处)。由于此数据模拟生成时所用的震源子波是不随炮集变化的,所以本发明进行变子波估计时产生的结果较为一致,见图11。From the processing results in Fig. 9 and Fig. 10, in the original input data Fig. 9a and Fig. 10a, the multiple waves and the same primary wave are mixed together, interfere with each other, and are indistinguishable, while the present invention realizes accurate primary wave, Multiple estimation and separation (especially where the arrows in Figure 7 point to). Since the source wavelet used in the generation of the data simulation does not change with the shot collection, the results generated when the variable wavelet estimation is performed in the present invention are relatively consistent, as shown in Fig. 11 .
图12展示了另外一种评价多次波估计技术有效性的方案。图12产生的本质是反馈迭代模型,即:本发明估计的一次波(图12b)作为二次震源传入地下来预测一阶表面相关多次波(图12c),一阶表面相关多次波(图12c)作为二次震源传入地下来预测二阶表面相关多次波(图12d),二阶表面相关多次波(图12d)作为二次震源传入地下来预测三阶表面相关多次波(图12e),三阶表面相关多次波(图12e)作为二次震源传入地下来预测四阶表面相关多次波(图12f),四阶表面相关多次波(图12f)作为二次震源传入地下来预测五阶表面相关多次波(图12g),等等以此类推。对于此数据,所预测的不同阶次的表面相关多次波(图12c至图12g)在原始输入数据(图12a)中可以被轻易地辨认识别出。本发明所估计的一次波、不同阶次的表面相关多次波的累加求和产生的总的数据(图12h)同原始输入数据(图12a)近乎完全一致,两者之间的差异(图12i)很小。Figure 12 shows another scheme for evaluating the effectiveness of multiple estimation techniques. The essence of Fig. 12 is a feedback iterative model, that is: the primary wave (Fig. 12b) estimated by the present invention is introduced into the ground as a secondary source to predict the first-order surface-related multiples (Fig. 12c), and the first-order surface-related multiples (Fig. 12c). (Fig. 12c) As a secondary source, the second-order surface correlated multiples (Fig. 12d) were introduced underground to predict the second-order surface-related multiples (Fig. 12d), and the second-order surface-related multiples (Fig. 12d) were introduced underground as a secondary source to predict the third-order surface correlated multiples. Secondary waves (Fig. 12e), third-order surface-related multiples (Fig. 12e) are transmitted underground as secondary sources to predict fourth-order surface-related multiples (Fig. 12f), and fourth-order surface-related multiples (Fig. 12f) The fifth-order surface-related multiples (Fig. 12g) are predicted to be transmitted underground as a secondary source, and so on. For this data, the predicted surface-correlated multiples of different orders (Figs. 12c to 12g) can be easily identified in the raw input data (Fig. 12a). The total data (Fig. 12h) generated by the cumulative summation of the primary wave and surface-related multiples of different orders estimated by the present invention is almost identical to the original input data (Fig. 12a), and the difference between the two (Fig. 12a) 12i) is very small.
图13进一步展示了本发明应用于Pluto 1.5数据中其它炮集的处理结果,可以看出一次波和多次波得以较精确的估计与分离。Fig. 13 further shows the processing results of the present invention applied to other shot sets in the Pluto 1.5 data. It can be seen that the primary and multiple waves are more accurately estimated and separated.
上面结合附图对本发明的实施例进行了描述,但是本发明并不局限于上述的具体实施方式,上述的具体实施方式仅仅是示意性的,而不是限制性的,本领域的普通技术人员在本发明的启示下,在不脱离本发明宗旨和权利要求所保护的范围情况下,还可做出很多形式,这些均属于本发明的保护之内。The embodiments of the present invention have been described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative rather than restrictive. Under the inspiration of the present invention, without departing from the scope of protection of the present invention and the claims, many forms can be made, which all belong to the protection of the present invention.
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