Multi-Azimuth Offset Vertical Seismic Profiles (VSPs) to Enhance Surface Seismic Images of Reservoirs

Zhao, Xiaomin¹, Yingping, Li¹, James Jackson¹, Shuangxi Wang², Guiqing Yao², Danli Zhang², Wenxue Zhang², Zhiren Yang², Yugui Wang², Xiangjie Dong² (1) VSFusion, A Baker Hughes-CGG Company, Houston, TX (2) Daqing Geophysical Exploration Company, Daqing, China

Although three-dimension (3D) surface seismic can provide images of subsurface struc­tures with certain accuracy borehole seismic survey is critical important to improve the images in a reservoir region with high resolution using three-component (3C) geophones placed in a well bore. In this paper, we applied 3C VSP processing techniques to one zero offset and 6 offset VSP (Vertical Seismic Profiling) data at different azimuths to enhance the subsurface structure images from 3D surface seismic.

This VSP survey was acquired from a vertical well in an oilfield in northeastern China. The 3C VSP data were recorded at a station spacing of 10 m to ensure high resolution VSP imaging of the subsurface structures. The zero offset VSP (ZVSP) was processing to obtain accurate velocity measurements and then built a high resolution velocity model for VSP-CDP transform and migration imaging. Offset VSP (OVSP) data were 3C rotated and separated to enhance different modes of reflected waves. The reflected wave fields were CDP trans­formed and migrated to generate high resolution images of subsurface structures. Images from ZVSP and OVSP, logging data, and a 3D surface seismic volume were visually integrat­ed by a 3D visualization system specially designed for VSP solutions. This study demon­strates the power of 3C processing of multifarious VSPs to enhance images of subsurface images in a reservoir region.