Continuously variable steered beam transducers for acoustic well logging

Claim 2

Electroacoustic transducer means for use in a fluid-filled well bore comprising: a plurality of individual piezoelectric transducer elements disposed longitudinally of one another along an axis and sized to permit passage through a well bore; a first plurality of inductors wound over permeable cores and in one-to-one association with said transducer elements; a second plurality of inductors connected in series relationship and in one-to-one association with said first plurality of inductors, said inductors and said transducer elements Forming an electrical delay line the value of inductance of each of said second plurality of inductors when taken together with that of the associated inductor of said first plurality of inductors being such as to optimize the condition for resonance of the inductor-piezoelectric transducer element delay line in a selected frequency range corresponding to the mechanical resonance frequency of said transducer elements; and means for controlling the magnetic permeability of said cores so as to control the value of inductance of said first plurality of inductors.

Claim 3

An electroacoustic transmitting transducer defined as in claim 1, further comprising; means for supplying electrical energy to be stored in said transducer elements; and means for triggering the release of said stored electrical energy from said transducer elements.

Claim 4

The apparatus of claim 1, wherein said means for controlling the magnetic permeability of the cores about which said first plurality of inductors are wound includes control windings about each of said cores and control circuit means for supplying selected DC currents to said control windings thereby providing a controlled magnetic biasing of said cores.

Claim 5

Acoustic well-logging transducer apparatus comprising: a plurality of individual capacitive piezoelectric transducer elements disposed longitudinally of one another along a longitudinal axis and sized to permit passage through a well bore; a first plurality of inductors wound over permeable cores and in one-to-one association with said transducer elements; a second plurality of inductors connected in series relationship and in one-to-one association with said first plurality of inductors so as to provide a delay line for sequentially controlling the activation of said capacitive transducer elements in a manner which cumulatively defines a beam of acoustic energy at an angle relative to said longitudinal axis of the transducer array, the value of inductance of each of said additional plurality of inductors when taken together with that of its associated inductor of said first plurality of inductors being such as to optimize the condition for resonance of the inductor-piezoelectric element delay line in a selected frequency range corresponding to the mechanical resonance frequency of said piezoelectric transducer elements; and remotely operable means for varying the magnetic permeability of said cores so as to vary the relative angle of said beam of acoustic energy with respect to said longitudinal axis.

Claim 6

Acoustic well-logging transducer apparatus comprising: a plurality of individual capacitive piezoelectric transducer elements disposed longitudinally of one another along a longitudinal axis and sized to permit passage through a well bore; a first plurality of inductors wound over permeable cores and in one-to-one association with said transducer elements; a second plurality of inductors connected in series relationship and in one-to-one association with said first plurality of inductors so as to provide a delay line for sequentially controlling the activation of said capacitive transducer elements in a manner which cumulatively defines a beam of acoustic energy at an angle relative to said longitudinal axis of the transducer array, the value of inductance of each of said additional plurality of inductors when taken together with that of its associated inductor of said first plurality of inductors being such as to optimize the condition for resonance of the inductor-piezoelectric element delay line in a selected frequency range corresponding to the mechanical resonance frequency of said piezoelectric transducer elements; and remotely operable means for varying the magnetic permeability of said cores so as to vary the relative angle of said beam of acoustic energy with respect to said longitudinal axis.