Abstract: The invention is a device and related method of finding from at least one receiver the location of a source of a transmitted acoustic signal. Both signal source and signal receiver are downhole. The invention uses either or both the triangulation method and the holographic method to determine signal location.The triangulation technique uses the relationships existing in Pythagorean's theorem to find source location. In contrast, the holographic technique uses a known velocity structure to assign propagation velocities to volume cells surrounding the receiver. By variational calculus, a ray path and start time may be assigned to a hypothetical source location for a particular receiver position. This is repeated for each receiver position. Where the hypothetical source locations and start times match for multiple receiver locations, the likely position of a source has been found.

Abstract: A transducer configuration of an acoustic sensing tool for determining the consistency of a first medium disposed between a layer having a greater acoustic reflectivity than the first medium and a second medium, the sensing tool including a rotating head, wherein the tool comprises first, second and third transducer pairs in a spaced apart configuration, each pair comprising a transmitting transducer for transmitting an acoustic radiation signal in an insonified zone, and receiving transducer having a receiving radiation pattern in a insonified zone, wherein the space between the transmitting and receiving transducers in each pair is constructed and arranged to allow the transmitting and receiving insonified zones to intersect behind but not in the acoustically reflective layer to null reverberation energy therefrom.

Abstract: A transducer configuration disposed within a wellbore sonde for acoustically imaging a target region behind an acoustically reflective layer includes a transmitting transducer for producing a transmitted acoustic beamspread pattern defined by a insonified zone having a width approximately equal to a width of the transmitting transducer and a transmitting main lobe beyond the transmitting collimated zone. The transducer configuration also includes a receiving transducer disposed adjacent the transmitting transducer. The receiving transducer includes an acoustic signal reception pattern defined by a insonified zone having a width approximately equal to a width of the receiving transducer and a receiving main lobe beyond the receiving insonified zone. A beamspread angle defines an amplitude contour forming an outer periphery of the transmitting and receiving main lobes.

Abstract: A system for acoustically imaging a target region behind an acoustically reflective layer includes a transducer configuration for acquiring acoustic image data from the reflective layer and target region, wherein the reflective layer and target region are divided into voxels circumferentially disposed about a central point. The system includes a mechanism for processing the data comprising a transmitting transducer for transmitting a first acoustic pulse, a receiving transducer for detecting a first arrival of a first acoustic reflection signal associated with the first acoustic pulse, and a mechanism for suppressing multiple reflected signals from the acoustic reflection signal associated with the first acoustic pulse, wherein the suppressing mechanism facilitates the acquisition of image data from the target region.

Abstract: A multi-part logging tool that allows measurement of several distinct independent parameters, which are in turn used to solve for secondary parameters that give information about the properties of the cement outside the casing. Secondary parameters affecting the measured signals are: casing thickness, bond of cement to casing, cement acoustic impedance, cement thickness, channel size and channel material. The present invention comprises a rotating tool that supports a plurality of specifically configured transducers that interrogate a region behind casing having a 10 degree azimuthal resolution and a depth of investigation of at least 0.75 inches behind casing. The transducers on the rotating tool include an array of angled beam transducers, a single-housing pitch-catch transducer and a radial, pulse echo transducer.

Abstract: A LWD tool is disclosed for detecting the existence of and distance to adjacent bed boundaries. A transmitter assembly generates either a short acoustic pulse or a swept frequency signal that is detected by an associated receiver assembly. The received signal(s) are conditioned and converted to high precision digital signals by an A/D converter. The digitized signals are accumulated and transferred to a digital signal processor via a high speed data bus. The digital signal processor also receives a digital signal representing the transmission signal and compares the transmission signal and the received signals together to enable a downhole microprocessor to derive a time lag for the received signals.