An-elastic seismic inverse methods for geological monitoring and energy development

获得准确和高分辨率的地下地质结构图的能力对于加拿大能源的可持续勘探/生产以及对二氧化碳地质封存地点的监测都是至关重要的。这些领域的技术和科学进步在经济、环境和社会领域的影响是巨大的。对从活动震源地震调查收集的数据应用波成像和反演技术是目前提供这些地图的最有效方法。该项目将涉及以下方面的系统研究：(1)有可能提供新的、直接和准确的地震反演程序的数学方法，以及(2)受地震衰减影响的地震数据的建模、成像、参数确定和分辨率增强问题，地震衰减是当地下对地震应力做出弹性响应时在地震数据中观察到的一种现象。将强调(1)和(2)的重叠方面：非弹性地球参数是地震数据与地下孔隙度、渗透率和应力下流体流动的各种指标之间的强大联系。因此，将这两条研究路线合并，为确定这些参数提供改进和可靠的方法，将意味着对含有隔离流体或碳氢化合物资源的地质体积中的应力和流动的性质和状态有更清楚的了解。逆散射理论将构成该项目的基础，以适应非弹性。在发展这一理论的过程中，将寻求非弹性岩性参数的线性和非线性直接估计和吸收补偿的新方法，这两种方法都减少了对先验信息的要求。通过对声学实例的研究，为反散射过程奠定了基础：通过对吸收目标的色散AVA特征的分析，证明了这些逆散射过程是可行的。在勘探相关研究中，这种细微差别类型的数据可变性才刚刚开始被报道。相关的次级项目包括采用类似的方法进行延时监测和探地雷达数据。

The ability to obtain accurate and highly-resolved maps of subsurface geological structure is critical, both for sustainable exploration/production of Canadian energy resources, and for monitoring of sites of geological sequestration of carbon dioxide. The impact, in economic, environmental, and social arenas, of technological and scientific advances in these areas is significant. Techniques of wave imaging and inversion applied to data collected from active-source seismic surveys are currently the most effective approach to providing these maps. This project will involve a systematic study of (1) mathematical methods that have the potential to provide new, direct, and accurate seismic inverse procedures, and (2) problems of modelling, imaging, parameter determination, and resolution enhancement of seismic data affected by seismic attenuation, a phenomenon observed in seismic data when the subsurface responds an-elastically to seismic stresses. Overlapping aspects of (1) and (2) will be emphasized: an-elastic Earth parameters are a strong link between seismic data and subsurface porosity, permeability, and various indicators of fluid flow under stress. Hence, merging the two lines of research, to provide enhanced and reliable methods for determination of these parameters, would mean a clearer picture of the character and state of stress and flow in a geological volume containing sequestered fluids or hydrocarbon resources. Inverse scattering theory, cast to accommodate an-elasticity, will form the foundation of the project. In progressing this theory, new methods for linear and non-linear direct estimation of an-elastic lithological parameters and absorption compensation, both occuring with reduced requirement for prior information, will be sought. Groundwork has been laid through study of the an-acoustic case: it has been shown that these inverse scattering procedures work through analysis of the dispersive AVA signatures of absorbing targets. This nuanced type of data variability is just beginning to be reported in exploration relevant studies. Connected sub-projects include the application of similar methods for time-lapse monitoring and ground-penetrating radar data.