Walkaway VSP多次波成像技术研究

Multiple reflection imaging by using Walkaway VSP data

北京大学地球与空间科学学院,北京100871

Wu Shiping, School of Earth and Space Sciences,Peking University,Beijing 100871,China

Walkaway VSP多次波成像是将地震相干应用于VSP中。首先讨论了Walkaway VSP多次波成像的基本原理。对比了传统VSP与Walkaway VSP多次波成像的照明区域之后,通过对模拟资料进行成像,讨论了影响成像的因素。模拟数据与实际数据的多次波成像结果表明,Walkaway VSP 多次波成像能够对井附近的结构较好地成像,从而拓宽VSP成像区域。应用过程中发现,多次波成像的深度和质量受地表反射能力以及检波器埋深的影响。地表反射能力越强,成像深度越深,成像的质量越高;检波器埋藏越深,成像结果对复杂地表的敏感度越小,成像的深度也将减小。

Multiple reflection imaging by using Walkaway VSP data is the application of seismic coherence to VSP data processing.Firstly,the basic principles of Walkaway VSP multiple reflection imaging was discussed.After analyzing the illumination region of traditional VSP and Walkaway VSP multiple reflection imaging,a synthetic example is modeled to discuss the factors affecting imaging.The multiple reflection imaging results of synthetic and actual VSP data indicate that multiple reflection imaging can give a good imaging of the side of the borehole,so as to improve the illumination region of the VSP imaging.During the processing,it is showed that the reflect ability of the surface and the depth of the receivers in the borehole affect the depth and the quality of the imaging.The stronger the reflecting ability of the surface,the imaging will be deeper and better.The deeper the depth of the receivers,the data will be less sensitive to the complex overburden,but the depth of the imaging will be shallower.