Borehole Acoustic Reflection Survey in Horizontal Wells: High Resolution Reservoir Structure to Guide Properties Distribution

Abstract

The article discusses the method of borehole acoustics reflection survey for detecting the presence and reconstructing the position of various reflecting surfaces, such as of large fractures, faults, bed-boundaries, in the near-well space at a distance up to 30m or more. The measurement principles, data processing, visualization and interpretation workflow developed by us based on the best published practices and supplemented by our solutions that significantly improve the quality and usability of the images are explained. A study of fractured zones identification and characterization in three horizontal wells based on the electrical microimager and the reflected acoustic survey is presented. Possibility of imaging the bed-boundaries of the host layers above and below the wellbore and specifying their position relative to the well's trajectory is demonstrated. Confinement of rocks with different reservoir quality within certain sub-layers of the target productive strata, identified with acoustic reflected survey, brings possibility to populate these properties more accurately in a refined structural model.