Patent ID: 6850462

Claim:
A method for detecting the characteristics of a cement annulus between a casing in a borehole and the surrounding earth formations in a slickline cement bond logging operation, the method comprising the steps of: lowering an acoustic logging tool within the borehole to a desired depth, the acoustic logging tool having at least an acoustic transmitting transducer, a primary acoustic receiving transducer and a longitudinally spaced secondary acoustic receiving transducer, the acoustic logging tool being suspended within the borehole by means of a slickline extending to the well surface; generating a pulse of acoustic energy from the transmitting transducer at a first point along said casing and transmitting said energy along said casing; receiving the acoustic energy transmitted along the casing with the primary receiving transducer at a second point along the borehole longitudinally spaced from the first point and producing an electrical signal representative thereof; receiving the acoustic energy transmitted along the casing with the secondary receiving transducer at a third point along the borehole longitudinally spaced from the first and second points and producing an electrical signal representative thereof; collecting amplitude and variable density data based upon the electrical signals and storing the data so collected in memory in a time amplitude matrix, the memory carried down hole by the logging tool; generating additional pulses of acoustic energy at timed intervals as the acoustic logging tool is moved within the borehole between known depths and storing the data collected in memory; retrieving the logging tool to the well surface and producing a cement bond log based upon the memorized data.