DOWNHOLE ACOUSTIC INSTRUMENT Russian patent published in 2007 - IPC E21B43/25 E21B28/00 B06B1/06 

FIELD: oil and gas production, particularly equipment to perform acoustic productive reservoir and perforation zone treatment to increase production from oil and gas wells and to perform remedial cementing.

SUBSTANCE: power is supplied to downhole acoustic instrument from constant current source. Downhole acoustic instrument includes a number of independent sections working on natural resonance section frequencies. Each section is arranged in sealed case and comprises service power source, filter module, protective module, basic frequency generator, automatic frequency adjustment module, summing unit and at least two piezoelectric converters with preselected resonance frequencies. Downhole acoustic instrument section also has phase equalizers to compensate resonance frequency dispersion of piezoelectric converters, power modules, current transformers and feedback probes. Number of phase equalizers is equal to number of piezoelectric converters. Each piezoelectric converter has its own control circuit including feedback probe, phase corrector, power module and current transformer serially connected with each other. Current transformer output is linked to frequency generator through summing unit and automatic frequency adjustment module.

EFFECT: increased acoustic power due to automatic frequency adjustment and phase equalization to compensate resonance frequency dispersion of piezoelectric converters in each section.

2 dwg, 3 cl