Fracture Evaluation Using Shock-Induced Borehole Waves

In the oil industry, acoustic techniques are commonly practiced to determine the position and the properties of the reservoir and the overburden. These techniques comprise the use of seismic surveys, cross-well tomography, and borehole logging. In the latter technique, acoustic sources and detectors are installed in a logging tool that is run in the borehole penetrating the potential hydrocarbon reservoir (i.e., a porous rock formation). The acoustic source generates a variety of borehole wave modes among which the Stoneley wave is most prominent [1]. In the field, the borehole is usually intersected by natural reservoir fractures and faults that may extend over several kilometers and dramatically affect the borehole acoustics [2]. Here we use a conventional vertical shock tube to generate and study wave propagation in a borehole intersected by a single horizontal permeable fracture.