Abstract:
As fine-scale exploration of unconventional oil and gas reservoirs advances, the need for high-resolution imaging of complex structures, such as fractures and cavities, near boreholes has become increasingly critical. To address the limited resolution of conventional acoustic logging tools, this paper presents a collaborative imaging method based on shear wave transformation and Kirchhoff integral migration. The approach is tailored for complex reservoirs and leverages a newly developed eight-directional acoustic logging instrument. The proposed method features multi-scale sparse representation capabilities, enabling effective extraction of weak reflected wave signals within the borehole environment and accurate imaging and localization of reflected wave energy. Its ability to identify karst cave systems and double-inclined interfaces has been validated through both theoretical simulations and real well data analysis. Results demonstrate that the method enhances the accuracy of reflected wave identification and improves the resolution of structural imaging. These findings offer technical support for the application of eight-directional logging instruments in geologically complex reservoir settings.