The Potential of Single-well Acoustic Imaging for Detecting the Direction and Distance to a Target Borehole

A new method to locate nearby boreholes using acoustic imaging is presented. The challenge of locating a nearby well from a borehole is commonly addressed with electromagnetic (EM) or passive magnetic ranging methods, which can suffer from poor resolution and penetration and require the presence of a conductive or magnetic casing. Single-well acoustic imaging has great potential for locating a nearby borehole at higher resolution and with fewer of the limitations of EM-based methods. Acoustic imaging requires only an impedance contrast between the target object and the formation, which is adequately provided by the presence of a fluid-filled borehole. Two tests are shown demonstrating the capabilities of the new method. In the first test, a vertical borehole is located and imaged from a nearby horizontal well, and in the second test, a vertical borehole is imaged from a nearby near-vertical well. In both cases the estimated distances were validated by independent measurements.