基于地震干涉法的波场重构及成像方法研究

The surface interferometry method is introduced into conventional reflection and refraction seismic exploration. This method retrieves surface waves with high signal-to-noise, we can obtain accurate velocity model by analysis and inversion of surface waves. The surface wave exploration technique is widely used in seismology and engineering geological exploration, however, under the scale of conventional oil and gas exploration, surface waves always are eliminated in conventional exploration seismic data processing. In this work, we utilized surface waves to solve the problem caused by complex near-surface because the high resolution of the surface-wave inversion at shallower levels, therefore, we provide a novel line of thought. The refraction interferometry theory is introduced into processing and analysis of passive seismic data set. Analysis of virtual refracted waves can be used to improve coverage of conventional refraction surveys and depth of investigation, enhance the signal-to-noise ratio the refractions at the far-offset traces and obtain characteristics of subsurface structure. This property of virtual refractions can be used for time-lapse monitoring to obtain time-lapse velocity variations. We establish a set of processing schedule and technical thought of passive seismic data set for obtaining good imaging of subsurface structure and details of shallow structure. Combined with processing results of active seismic data set, we also provide a technical thought of joint application of passive seismic exploration and active seismic exploration.

提出将面波干涉方法引入到常规反射波及折射波地震勘探中，构建出高精度面波响应，通过面波分析和反演获得准确的地下速度模型。面波勘探技术广泛用于天然地震学及工程地质勘探，鉴于面波对浅层地质构造的高分辨率，我们在常规油气勘探尺度下，利用数据处理中常作为干扰而被消除的面波响应，为解决复杂近地表异常面临的挑战提供一种新的技术思路。将折射干涉理论引入到被动源地震数据的处理和分析中，虚拟折射分析能够改善常规折射测量的地下覆盖范围和探测深度，提高远偏移距处折射波的信噪比，获得更准确的地质构造特征。将折射干涉理论进一步用于被动源时移地震测量，监测地下速度场的变化。利用地震干涉理论建立一套被动源地震勘探的有效处理流程和技术路线，既能获得较好的地下地质构造的成像结果，又能细化浅层地质构造的信息；同时通过与主动源数据处理结果相结合，也为被动源勘探与主动源勘探的联合应用提供一种有实用价值的技术思路。