Fine Characterization of Volcanic Rock Morphology by Walkaway VSP Technique

Because the wave impedance of volcanic rocks is not much different from that of surrounding rocks, it is difficult to accurately describe the morphology of special lithologic bodies such as volcanic rocks. In order to solve the problem, the method of accurately describe the morphology of volcanic rocks using Walkaway-VSP data was studied. The volcanic rocks and surrounding rocks of the Walkaway-VSP data have obvious wave impedance interfaces. The processing produce based on the principle of “fidelity” is adopted to protect the effective information of volcanic rock reservoirs and provide a good data foundation for the accurate description of volcanic rocks. Santanghu Basin in Tuha Oilfield in western China is a typical tight oil enrichment area in China. Through fine processing and interpretation of Walkway-VSP data of M68（oil well name）in the area, high-resolution and high-fidelity Walkway-VSP longitudinal wave imaging results are obtained, which not only determine the shape and plane distribution characteristics of source rock and volcanic rock reservoirs, but also finely identify their lithologic interfaces in the longitudinal direction, and achieve good fine characterization effect.