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Yuanqiang Li Jingye Li Xiaohong Chen Jian Zhang Xin Bo 《Geophysical Prospecting》2020,68(7):2009-2026
The conventional impedance inversion method ignores the attenuation effect, transmission loss and inter-layer multiple waves; the smooth-like regularization approach makes the corresponding impedance solution excessively smooth. Both fundamentally limit the resolution of impedance result and lead to the inadequate ability of boundary characterization. Therefore, a post-stack impedance blocky inversion method based on the analytic solution of viscous acoustic equation is proposed. Based on the derived recursive formula of reflections, the 1D viscous acoustic wave equation is solved analytically to obtain zero-offset full-wave field response. Applying chain rule, the analytical expression of the Fréchet derivative is derived for gradient-descent non-linear inversion. Combined with smooth constraints, the blocky constraints can be introduced into the Bayesian inference framework to obtain stable and well-defined inversion results. According to the above theory, we firstly use model data to analyse the influence of incompleteness of forward method on seismic response, and further verify the effectiveness of the proposed method. Then the Q-value sensitivity analysis of seismic trace is carried out to reduce the difficulty of Q-value estimation. Finally, the real data from Lower Congo Basin in West Africa indicate that the proposed approach provide the high-resolution and well-defined impedance result. As a supplement and development of linear impedance inversion method, the non-linear viscous inversion could recover more realistic and reliable impedance profiles. 相似文献
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随着石油勘探难度的进一步加大,地震数据往往存在采样不规则、地震道缺失等现象,如果不对其进行处理,会对后续的地震成像产生影响,引入成像噪音.针对这一问题,一般是通过地震道插值或数据规则化对叠前数据进行处理,然后采用常规的偏移方法进行成像,本文则是将地震成像看作最小二乘反演问题,在共成像点道集引入平滑算子,在共偏移距/角度道集引入平面波构造算子(PWC)进行约束,通过预条件共轭梯度法使得反偏移后数据与输入数据之间的误差达到最小,最终得到信噪比更高、振幅属性更为可靠的成像结果.理论模型和实际资料处理表明,本文方法不仅可以有效压制数据不规则对成像产生的噪音,而且具有更高的成像精度. 相似文献
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Inversion for seismic impedance is an ill-posed and band-limited problem so that inversion results are non-unique and unstable and low and high frequency components of inversion results are missed. Combining regularization with constraints of sonic log data and geological structure information can help to alleviate these problems. To achieve this, we developed an inversion method by constructing a new objective function which includes edge-preserving regularization and soft constraint based on Markov random field (MRF). The method directly introduces absolute constraints with prior impedance and sonic log data in the objective function and indirectly achieves relative constraints with geologic structures of layer interfaces and faults by adjusting the regularization parameter which is the scaling parameter δ. Moreover, we improved the inversion result using anisotropic diffusion smoothing method. Optimization approach utilized in inversion is a fast simulated annealing (FSA). We test the method on both synthetic and field data examples. Tests on 2-D synthetic data indicate that aspects of the discontinuity in the inversion results are significantly improved by adding δ values in faults and layer interfaces. We obtained better results by combining the first-order neighborhood and the third-order neighborhood of MRF. The inversion results of the field data provide more detailed information of the layers. The results of nearby faults were improved by introducing the geological structure constraints. 相似文献
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Time-lapse monitoring is a powerful tool for observing dynamic changes in the subsurface. In particular it offers the potential for achieving inversion results with increased fidelity through the inclusion of complementary information from multiple time-steps. This inclusion of complementary information can reduce the need for spatial smoothing, without adding inversion artifacts to the resulting images. Commonly used time-lapse inversion methods include the ratio method, cascaded time-lapse inversion, difference inversion and differencing independent inversions. We introduce two additional methods in which both time-lapse data sets are inverted simultaneously. In the first, called temporally constrained time-lapse inversion, inversion of both datasets is done under a single optimization procedure and constraints are added to the regularization to ensure that the changes from one time to another are smooth. In the second method, called simultaneous time-lapse inversion, the inversions at time 1 and time 2 are performed simultaneously and constraints of smoothness and closeness to a reference model are applied to the difference image produced at each iteration, and subsequently, the constraints are updated at each iteration. Through both a numerical and a field example we compare the results of common time-lapse inversion methods as well as the introduced approaches. We found that of the commonly used time-lapse inversion methods the difference inversion method produced the best resolution of time-lapse changes and was the most robust in the presence of noise. However, we found that the alternative approach of simultaneous time-lapse inversion produced the best reconstruction of modeled EC changes in the numerical example and easily interpretable high resolution difference images in the field example. Moreover, there was less tailoring of regularization parameters with our simultaneous time-lapse approach, suggesting that it will lend itself well to an automated inversion code. 相似文献
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Inversion for seismic impedance is an inherently complicated problem. It is ill‐posed and band‐limited. Thus the inversion results are non‐unique and the process is unstable. Combining regularization with constraints using sonic and density log data can help to reduce these problems. To achieve this, we developed an inversion method by constructing a new objective function, including edge‐preserving regularization and a soft constraint based on a Markov random field. The method includes the selection of proper initial values of the regularization parameters by a statistical method, and it adaptively adjusts the regularization parameters by the maximum likelihood method in a fast simulated‐annealing procedure to improve the inversion result and the convergence speed. Moreover, the method uses two kinds of regularization parameter: a ‘weighting factor’λ and a ‘scaling parameter’δ. We tested the method on both synthetic and field data examples. Tests on 2D synthetic data indicate that the inversion results, especially the aspects of the discontinuity, are significantly different for different regularization functions. The initial values of the regularization parameters are either too large or too small to avoid either an unstable or an over‐smoothed result, and they affect the convergence speed. When selecting the initial values of λ, the type of the regularization function should be considered. The results obtained by constant regularization parameters are smoother than those obtained by adaptively adjusting the regularization parameters. The inversion results of the field data provide more detailed information about the layers, and they match the impedance curves calculated from the well logs at the three wells, over most portions of the curves. 相似文献
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通过地震海洋学联合调查航次,获得了同时采集的高分辨率多道地震数据与水文数据（XBT）联合调查数据.通过针对性处理获得了清晰的海洋水体反射地震剖面,捕捉到南海东北部次表层涡旋,证明了该调查方法的有效性.利用背景场约束反演方法得到海水的波阻抗、声速、密度、温度和盐度剖面,揭示了涡旋具有相对低速、高密、低温与高盐特征.处理和反演结果表明,在浅部和部分噪声较强和无约束反演区域,结果误差较大,可靠性较低.调查结果说明,获得较高信噪比的原始高分辨率地震资料采集技术方法、联合约束数据的获取、针对性的特殊处理方法和有效的反演方法是地震海洋学资料有效分析利用的重要保证. 相似文献
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通过把地层格架信息作用于立体层析Fréchet导数矩阵,使得更新后的速度模型呈现出符合地质规律的块状特征.地层格架信息基于立体层析反演中得到的反射点位置进行非规则B样条插值拟合得到,因此在反演中它将会随着反射点位置的更新自然得到更新.与前人提出的保边缘层析算法或多层立体层析算法相比,本文提出的地层格架正则化无需引入混合正则化项或定义某种复杂的混合速度格式,更为直接也更容易实现.理论和实际数据算例证实了该正则化技巧的稳健性和可靠性,能够得到与实际地质构造特征更为一致的地质一致性反演结果. 相似文献
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地震反演是储层定量描述和地震油气识别的关键技术,反演结果在复杂构造区域的横向连续性和保真性是影响地震资料定量解释精度的重要因素.基于此,本文发展了地震数据互相关驱动的多道反演方法.考虑地层反射系数与地震数据在结构上具有相似性的特点,基于地震数据互相关描述地层反射系数的结构特征,并将其作为多道地震反演的横向约束条件;此外,为改善地震数据本身横向连续性差对反演结果的影响,在目标泛函的惩罚项中引入局部优化算子,构建了一个易于求解的多道地震反演目标泛函.与常规多道地震反演方法相比,本文方法能够设计更合理、更符合实际情况的横向约束算子,提高反演结果的横向连续性,并且能有效降低地震资料质量对反演结果的影响.模型测试和实际应用验证了本方法的可靠性和稳定性. 相似文献
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基于模型的波阻抗(速度)反演中,约束是不可缺少的,它可以有效地减少反演多解性和提高运算效率.国内外大量学者均详细论述了一些反演的约束手段,但对于地震道与地震道之间的约束,除了采用测井外推模式之外,就鲜有介绍,相同的约束条件直接应用于全部的地震道,不再变化,这样势必会增加运算时间和影响反演效果.针对这些问题,本文描述了一种地震相关性分段约束速度反演的方法,其目的在于增加内在的道与道之间的约束,主要采用了地震道的相关特征去优化约束条件与减少反演计算量.本文先分析了地震反演的不同内在约束方法,并利用地震的相关性去分段自动选择约束的强弱与范围大小,而不是在全部地震道反演中采用相同的约束参数,即可大大优化运算效率;其次设计两个数学模型进行反演验证,在反演效果比较符合实际的基础上,运算时间大大减少;最后引入中国东部某地区的实例对该方法进行检验,反演剖面上可以清楚观察出冲积扇的沉积特点,各期砂体清晰可见,便于追踪解释与储层预测,具有较高的分辨率与可信度.结果表明该方法是一种有利于提高反演效果和效率的方法. 相似文献
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针对目标区下第三系储层横向变化快,沉积特征不明显等特点,为提高滚动探井、开发井的钻探成功率,本文研制形成一套具有针对性的油气藏勘探预测研究方法.即运用多井约束波阻抗地震反演方法来预测砂体展布,同时对生成的地震波阻抗反演数据体中的振幅、厚度等暗含的有效信息进行提取,对砂体的分布范围及厚度变化进行准确而精细的描述和预测,最终依据此法优选有利相带,部署井位,取得了很好的勘探开发效果. 相似文献
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The travel time and amplitude of ground-penetrating radar (GPR) waves are closely related to medium parameters such as water content, porosity, and dielectric permittivity. However, conventional estimation methods, which are mostly based on wave velocity, are not suitable for real complex media because of limited resolution. Impedance inversion uses the reflection coefficient of radar waves to directly calculate GPR impedance and other parameters of subsurface media. We construct a 3D multiscale stochastic medium model and use the mixed Gaussian and exponential autocorrelation function to describe the distribution of parameters in real subsurface media. We introduce an elliptical Gaussian function to describe local random anomalies. The tapering function is also introduced to reduce calculation errors caused by the numerical simulation of discrete grids. We derive the impedance inversion workflow and test the calculation precision in complex media. Finally, we use impedance inversion to process GPR field data in a polluted site in Mongolia. The inversion results were constrained using borehole data and validated by resistivity data. 相似文献
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有别于传统基于梯度信息的反演方法在正则化约束中用总梯度逼近海塞逆矩阵的技术,本文将正则化约束问题的数据拟合项和模型光滑项分开考虑,只利用数据拟合函数的梯度信息对数据拟合项的海塞矩阵进行逼近,通过求解类高斯牛顿下降方向方程得到不依赖前几次迭代正则化因子的更精确下降方向,在求解当前迭代下降方向的过程中,通过保证右端项中两个向量的二范数在同一数量级的原则,实现了正则化因子的自动更新.对理论模型的试算表明这种自适应正则化反演方案可以在拟牛顿反演框架下基本达到OCCAM的算法稳定性,反演结果对初始模型依赖性较小,同时又无需在一次迭代中多次搜索最佳正则化因子.本文还基于此算法讨论了大地电磁各参数对于反演结果的影响,由于本文的反演结果能得到充分的正则化约束,因而在此框架下讨论阻抗和倾子在反演中的作用相对更为客观. 相似文献
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本文针对蒸汽辅助重力泄油(SAGD)生产中开发监测问题,发展了综合应用地震及重力数据反演储层密度的联合反演算法.通过测井数据建立纵波阻抗与密度的直接关系,并推导出这种关系下重力与纵波阻抗数据联合反演的计算方法,从而计算出蒸汽腔体密度分布规律.文中应用密度反演后验约束正则化方法,采用Tikhonov正则化模型,通过波阻抗数据作为约束进行联合反演,在算法上提高了稳定性,同时得到较高的反演精度.文中对SAGD生产中的理论模型进行了方法试算,并分析了算法的误差,最终应用于SAGD生产的实际数据中,通过最终反演结果分析,该方法取得了很好的应用效果. 相似文献
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In this paper, we develop a general approach to integrating petrophysical models in three-dimensional seismic full-waveform inversion based on the Gramian constraints. In the framework of this approach, we present an example of the frequency-domain P-wave velocity inversion guided by an electrical conductivity model. In order to introduce a coupling between the two models, we minimize the corresponding Gramian functional, which is included in the Tikhonov parametric functional. We demonstrate that in the case of a single-physics inversion guided by a model of different physical type, the general expressions of the Gramian functional and its gradients become simple and easy to program. We also prove that the Gramian functional has a non-negative quadratic form, so it can be easily incorporated in a standard gradient-based minimization scheme. The developed new approach of seismic inversion guided by the known petrophysical model has been validated by three-dimensional inversion of synthetic seismic data generated for a realistic three-dimensional model of the subsurface. 相似文献
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针对利用地震道进行相对波阻抗反演中遇到的横向连续性难以保持、初始子波容错度差以及随机噪声干扰影响反演结果等问题,提出了一种基于矩阵Toeplitz稀疏分解的相对波阻抗反演方法.该方法将地震数据剖面的Toeplitz稀疏分解问题分解为两个子反演问题,其一以Toeplitz子波矩阵元素为待反演的参数,用Fused Lasso方法求解,可保证子波具有紧支集且是光滑的;其二以稀疏反射系数矩阵元素为待反演参数,用基于回溯的快速萎缩阈值迭代算法求解,大大降低了目标函数中参数选择的难度.通过交替迭代求解上述两个子反演问题可将地震数据剖面因式分解为一个Toeplitz子波矩阵和一个稀疏反射系数矩阵;然后由反射系数矩阵递推反演可以得到高分辨率的相对波阻抗剖面;利用测井资料加入低频分量后,也可得到高分辨率的绝对波阻抗剖面.Marmousi2模型生成的合成记录算例和实际地震资料算例均表明:本文方法可以从带限地震数据中有效地反演相对波阻抗,反演结果分辨率高并且能够很好地保持地震数据的横向连续性;即使在初始估计子波存在误差和地震数据被随机噪声污染的情况下也能取得较好的效果. 相似文献
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深部储层地震资料通常照明度低、信噪比低、分辨率不足,尤其是缺乏大角度入射信息,对深部储层流体识别存在较大影响.Gassmann流体项是储层流体识别的重要参数,针对深层地震资料的特点,本文首先在孔隙介质理论的指导下,推导了基于Gassmann流体项与剪切模量的两项AVO近似方程.通过模型分析,验证了该方程在小角度时与精确Zoeppritz方程误差很小,满足小角度入射条件下的近似精度要求.然后借助Connolly推导弹性阻抗的思想,推导了基于Gassmann流体项与剪切模量的两项弹性阻抗方程.针对深部储层地震资料信噪比差的特点,利用奇偶反射系数分解实现了深部储层基追踪弹性阻抗反演方法,最后提出了基于基追踪弹性阻抗反演的Gassmann流体项与剪切模量的求取方法,并将提取的Gassmann流体项应用于深部储层流体识别.模型测试和实际应用表明该方法稳定有效,具有较好的实用性. 相似文献