走向精确地震勘探的道路

Pathway toward accurate seismic exploration

勘探地震领域已扩展到复杂地表、复杂构造、复杂油藏和深层目标等。地震数据采集技术发展到了宽方位、高密度、宽频带(“两宽一高”)地震数据采集阶段;地震波成像技术发展到了贝叶斯(Bayes)参数估计理论下的全波形反演(FWI)和最小二乘逆时深度偏移成像(LS_RTM);油藏描述发展到了综合信息利用和最佳判定阶段;地震勘探技术已经发展至全新的阶段。横向缓变的层状介质假设、地表一致性假设、射线理论波传播和Zoeppritz方程界定了上一代精确地震勘探的方法技术及其适用性,上一代精确地震勘探以高分辨率地震子波作为成像处理的核心目标,并据此开展薄层油气藏的识别、描述与评价。而描述任意介质中地震波传播的波动理论和贝叶斯参数估计理论构成了新一代高精度地震勘探的理论基础。“两宽一高”的地震数据采集技术和更高精度的子波处理;基于高维、字典基和稀疏特征表达的信号处理技术(解决去噪、数据规则化、数据压缩、去混叠等问题)、建立更精确速度和Q值模型以及估计宽带反射系数的特征波反演成像技术、宽带波阻抗成像技术和基于信息综合的人工智能油藏描述技术代表了走向精确地震勘探的未来方向。

The domain of seismic exploration has expanded to cover complex topographies,complex subsurface structures,complex reservoirs,and deep geological targets.The new generation of accurate seismic exploration methods entail wide-azimuth,wide-frequency band,and high-density seismic data acquisition.In these methods,full-wave inversion,and least-square reverse time migration methods based on Bayes estimation theory have become the standard for imaging,and reservoir characterization is implemented with integrated information utilization and optimal inference.Evidently,seismic exploration has entered a new era.For the last-generation accurate seismic exploration,the assumption of consistence for layers and surfaces,the ray-theory wave propagation,and Zoeppritz equations define the scope of seismic data processing and its applicability.A high-resolution seismic wavelet is the key objective of seismic data acquisition and imaging methods,based on which the identification,characterization,and evaluation of thin reservoirs is carried out.In new-generation methods,the theoretical basis is enriched by a number of tools,namely:the Bayesian estimation theory and wave equations that describe wave propagation in complex media.The seismic data acquisition with wide-azimuth,wide-frequency band,and high-density sampling;accurate seismic wavelet processing;amplitude and phase preserving signal processing based on high dimension,dictionary bases and sparse representation;characteristic wave inversion for accurate velocity model building;Q model building and wideband reflectivity estimation;wideband impedance model building;and reservoir characterization with integrated information utilization and artificial intelligence,all of these methods provide novel pathways for accurate seismic exploration.