塔里木盆地巴麦地区的地震资料受复杂地震地质条件的影响,层间多次波广泛发育,识别和压制难度大,导致奥陶系碳酸盐岩断控缝洞型储层成像不准确,制约了该地区油气勘探部署。通过模型正演及邻区VSP波组特征标定分析,明确了层间多次波产生的必要条件、发育特征及对有效反射信号的影响,并有效识别出二叠系火成岩巴楚组标准灰岩、二叠系不整合面小海子组灰岩等多套产生层间多次波的“源镜”组合,形成了“两步法”层间多次波叠后压制技术:首先利用多次波分布规律,采用匹配追踪法压制层间多次波;然后基于剖面频率特征,利用优势频率信息提取技术,压制高频层间多次波并增强资料信噪比。研究区实际资料处理结果表明,该方法能够有效压制奥陶系内幕层间多次波,提升目的层断控碳酸盐岩缝洞型储层成像质量。

<p>&nbsp;In the Bamai area of the Tarim Basin,internal multiples are widely developed due to the complex seismic geological conditions.These multiples are difficult to identify and suppress,which leads to inaccurate imaging of fault-controlled carbonate fractured vuggy reservoirs and restricts the deployment of oil and gas exploration.Based on the analysis of the forward modeling method and the calibration of the wave characteristics of drilling VSP data,this study defines the prerequisite for the formation of internal multiples.The development characteristics and their influence on the effective reflection signal were determined.Multiple sets of &ldquo;source mirror&rdquo; combinations were effectively identified,such as the Permian igneous rock-Bachu Formation standard limestone and Permian unconformity surface-Xiaohaizi limestone formation.A &ldquo;two-step&rdquo; poststack internal multiple suppression method was formed.First,based on the understanding of the multiple distribution law,the matching pursuit method was used to suppress internal multiples; second,based on the frequency characteristics,the dominant frequency band was extracted to suppress the high-frequency internal multiples and enhance the SNR of the data.The field data results show that this method can effectively suppress Ordovician internal multiples and improve the imaging quality of fault-controlled carbonate fractured vuggy reservoirs.</p>

复杂的火成岩或膏岩层强反射界面产生的层间多次波对一次波有强烈的干涉效应, 精准识别层间多次波并对其进行预测和压制是地震资料处理的技术瓶颈之一。常规的叠前数据驱动的层间多次波预测与压制方法需要预测每个反射界面产生的多次波, 效果不佳且运算量非常大。为此, 提出基于层控数据驱动的层间多次波预测与压制方法, 从层间多次波正演模拟出发, 分析了对目的层有影响的层间多次波的产生来源和形成的地质条件, 再利用井标定的井震匹配情况和构造模型多次波正演模拟记录进行对比确定, 将产生多次波的主要反射界面作为层控模型层, 从而减少对所有多次波进行预测的运算量, 再采用逐层预测和压制的思路, 保证预测的层间多次波的有效性, 最后, 采用保护指定有效地层的最小二乘自适应匹配相减技术进行层面多次波的压制。模拟数据和实际资料的处理结果表明, 该方法能够有效预测和压制有影响的层间多次波, 从而消除假构造, 提高了地层构造、断裂和缝洞型储层的成像精度。

Internal multiples generated by the strong reflection interface of complex igneous rock or gypsum rock strongly interfere with the primary reflection.Accurate identification, prediction, and suppression of these internal multiples are technical bottlenecks in seismic data processing.The conventional pre-stack data-driven method for predicting and suppressing the internal multiples generated by each reflector is inefficient and computationally expensive.Therefore, a layer-controlled data-driven method was proposed to predict and suppress the internal multiples.First, based on internal multiple forward modeling, the generating source and geological conditions of the formation of internal multiples that affect the target zone were analyzed and obtained.Second, the source of the internal multiples was further determined by comparing the calibrated seismic matching conditions with the forward modeled internal multiple.Third, the main generating reflectors of the multiples were considered as a layer-controlled model, and a layer-by-layer prediction and suppression process was adopted to predict the internal multiples and reduce computational cost.Finally, the protected least-squares adaptive subtraction method was used to suppress the multiples.The synthetic and field data test results showed that this method can effectively predict and suppress internal multiples that strongly interfere with the target.This can eliminate false structures and improve the imaging accuracy of stratigraphic structures, fractures, and fracture-vuggy reservoirs.

逆散射级数法在有效预测层间多次波的同时,面临着一次波和多次波叠加的干扰,为解决压制多次波时保护有效信号不被损伤的问题,开展了逆散射级数层间多次波压制方法的研究。首先从理论上推导并阐述了逆散射级数层间多次波压制方法的物理机制,然后改进常规层间多次波压制处理流程,在逆散射级数法预测层间多次波前、后去除和补偿子波来提高层间多次波预测的准确性,从而降低对自适应相减的依赖度。该方法完全由数据驱动,无需人工干预和先验信息,适用于复杂地形和地质情况的层间多次波压制。模型数据和实际数据应用结果证明了方法的有效性和适用性。

In seismic exploration,due to the interference and overlay of primaries and internal multiples,it is difficult to remove internal multiples,and sometimes,subtracting internal multiples will damage the effective signals.Hence,based on the scattering theory,the inverse scattering series internal multiple attenuation method is discussed,with a detailed demonstration of its physical and mathematical foundations.Moreover,the processing flow is modified by accommodating the source wavelet effect to improve the accuracy of the prediction of the internal multiple and reduce dependence on the adaptive subtraction.This method is completely data-driven and does not require any subsurface information.It is applicable to complex topography and geology.The numerical and field data tests show the validity and applicability of the inverse scattering series internal multiple attenuation method.

层间多次波给地震成像和解释带来极大挑战,单独使用基于波动方程预测或基于滤波的方法压制层间多次波效果都不理想,前者对数据的品质要求高且运算量大,而后者则很难处理规律性较差的层间多次波。基于此,提出了一种将逆散射级数法与抛物线Radon变换相结合的层间多次波压制新策略。首先在抛物线Radon域采用自适应非线性滤波对CRP数据中的一次波进行保护处理,将未受多次波干扰的一次波和含有部分一次波的多次波能量进行分离,然后在曲波域对滤波分离出的多次波能量和逆散射级数预测的层间多次波模型数据进行匹配相减,最后将相减得到的剩余一次波和滤波分离出的一次波相融合得到层间多次波压制后的结果。实际资料测试表明该策略能高效高精度压制层间多次波,使地层结构特征更为清楚,地震成像质量显著改善,从而为油藏解释提供更可靠的地震数据。

相比于传统匹配相减方法,模式学习方法将多次波衰减分成多次波模式学习和自适应相减的两个独立过程,因而能够更好地保护一次波。然而,由于多次褶积的影响,预测多次波模型存在相位、频带、振幅误差。为了在不损伤一次波的基础上,尽可能减少多次波残留,提出了基于伪地震数据的模式学习方法。利用预测地震道,得到其Hilbert变换道以及预测道和Hilbert变换道的一阶导数,作为伪地震数据的4个分量,补充预测多次波模型中相位和高频信息。模式学习阶段利用主成分分析法分别学习伪地震数据4个分量的多次波字典矩阵,然后按列拼接得到联合字典矩阵;自适应相减阶段基于学习到的联合字典矩阵,利用裂步Bregman算法从原始地震数据中重构多次波,实现一次波和多次波的分离。模拟数据和实际资料处理结果表明,该方法在保护一次波的同时,能有效压制多次波,模型数据的一次波信噪比提升了1dB。

Diffracted multiples are a major problem in which zones are characterized by steep slopes and rugged seafloors.It is difficult to predict out-of-plane diffracted multiples via SRME owing to insufficient near-offset and negative-offset information,which results in phase,frequency,and amplitude errors in the predicted multiples.To suppress multiples without damaging the primaries,we propose an alternative method that applies pattern learning to pseudo-seismic data.Compared with traditional matching filter methods,pattern-learning methods suppress multiples via pattern coding and adaptive suppression,which better protects the primaries.Pseudo-seismic data,also known as mathematical adjoints of a predicted trace,include its first derivative,the Hilbert transform,and the derivative of the Hilbert transform,which provide additional phase and high-frequency information.Specifically,the proposed method was implemented in a two-stage process.First,in the pattern-coding stage,the pattern dictionary was obtained using principal component analysis for each component of the pseudo-seismic data,and the joint dictionary matrix consisted of all sets of key patterns from the pseudo-seismic data.Second,in the adaptive attenuation stage,the joint dictionary matrix from the pseudo-seismic data was utilized to estimate the multiples in the recorded data to separate the primaries and multiples,using the split Bregman algorithm.The proposed method,on the one hand,inherits the advantages of the pattern-learning method and protects the primaries better.On the other hand,additional phase and high-frequency information from the pseudo-seismic data can be utilized to suppress the residual diffracted multiples.We validated this approach using synthetic and field datasets.Our method yielded an SNR improvement of 1dB for synthetic data.In addition,for the field data,the residual diffracted multiples were substantially reduced using the proposed method.

层间多次波的存在严重影响地震资料品质,造成合成地震记录与实际资料不匹配,对油气勘探开发造成许多负面影响。由于层间多次波来自表层以下的反射位置,因而与一次波差异小,且多源叠加造成多次波周期性特征复杂,目前还没有非常有效的压制方法可以借鉴。针对层间多次波&ldquo;识别难,压制难&rdquo;问题,在广泛技术调研的基础上,改变思路,提出了一种处理解释一体化的层间多次波识别与压制技术方案,以四川盆地高石梯&mdash;磨溪地区灯影组为例,介绍其实际应用效果。首先,研发了基于反射率法的多次波正演模拟技术,通过含与不含多次波正演模拟结果与实际资料对比分析,结合其它多种手段论证了高石梯&mdash;磨溪地区井震不匹配主要是由层间多次波造成的,并得到VSP资料的验证。其次,利用剥层法多次波正演模拟与周期性分析,明确了灯影组层间多次波主要来源于其上覆4组速度反转层。其后,在层间多次波模拟与来源层位指导下,通过多次波压制试验优选技术,建立了偏移前、偏移后和叠后分步组合迭代的多次波压制技术流程,并通过层控剩余速度分析与叠加速度优化,以及层控Radon变换解决了层间多次波与一次波速度差异小的瓶颈问题。最后,基于速度谱上速度展度,研发了多次波发育强度平面预测技术,形成了点、线、面完整的多次波压制处理质控技术,保障了在压制多次波的同时不伤及有效波。该技术方案在高石梯&mdash;磨溪地区已经得到规模化应用,落实了超深层地层结构,取得了显著地质效果;在GS1井区应用中提高了井震匹配程度,储层预测符合率提高了20%以上;在GS19井区应用中首次在灯影组内幕发现了大量弱&ldquo;串珠&rdquo;反射,它们是未来重要的资源接替区;在高石梯东地区应用中消除了台缘带假像,降低了井位部署风险。