公开(公告)号：US20190017371A1

公开(公告)日：2019-01-17

申请号：US16080600

申请日：2017-03-03

Applicant: XACT Downhole Telemetry Inc.

Inventor： John Godfrey McRory

IPC: E21B47/16 ,  E21B47/06

CPC classification number: E21B47/16 ,  B06B1/0611 ,  E21B47/065 ,  G01V1/22

Abstract: Methods, systems, and techniques for controlling voltage applied across a piezoelectric stack of a downhole acoustic transmitter. At least one of the temperature of the stack and the compressive stress applied to the stack is monitored. At least one of the temperature of the stack and the compressive stress applied to the stack is compared to a temperature threshold and a stress threshold, respectively. When the stack signal is an alternating voltage signal and when at least one of the temperature of the stack and the compressive stress applied to the stack respectively exceeds the temperature threshold and the stress threshold, the stack signal is modified such that a negative polarity portion of the stack signal has a maximum magnitude less than a magnitude of a negative polarity limit.

公开(公告)号：US20150377017A1

公开(公告)日：2015-12-31

申请号：US14766421

申请日：2014-02-07

Applicant: XACT DOWNHOLE TELEMETRY INC.

Inventor： John Godfrey McRory

IPC: E21B47/16

CPC classification number: E21B47/16 ,  B06B1/0215 ,  B06B2201/55 ,  B06B2201/73 ,  E21B47/14

Abstract: An acoustic transmitter for transmitting an acoustic signal through a downhole medium includes a voltage source; a composite load; and switching circuitry that applies voltage from the voltage source across the composite load in response to a drive signal. The composite load includes charge control circuitry, in the form of at least one inductor, connected electrically in series with a piezoelectric transducer that may be electrically modeled as a capacitor.

Abstract translation: 用于通过井下介质发送声信号的声发射器包括电压源; 复合载荷 以及响应于驱动信号，从电压源跨复合负载施加电压的开关电路。 复合负载包括以至少一个电感器的形式的电荷控制电路，该电感器与可被电气建模为电容器的压电换能器电串联连接。

公开(公告)号：US20190301280A1

公开(公告)日：2019-10-03

申请号：US16316848

申请日：2017-07-07

Applicant: XACT Downhole Telemetry Inc.

Inventor： Xiaojun Xiao ,  Dave Whalen ,  John-Peter Van Zelm ,  John Godfrey McRory

IPC: E21B47/16

Abstract: A downhole acoustic transmitter has a pre-loaded piezoelectric transducer, an enclosure in which the piezoelectric transducer is housed, a preload spring that biases the transducer against a first end coupling of the enclosure, and an adjustable preload means mounted to the enclosure such that a selected compressive force is applied to the preload spring, which in turn urges the transducer against a face of the first end coupling such that a mechanical preload is applied to the transducer. The position of the adjustable preload means and the spring compliance are selected so that the level of mechanical preload applied to the transducer compensates for an expected amount of flexing of the acoustic telemetry transmitter due to varying tension and compression applied to the transmitter, thereby maintaining an effective preload on the transducer.

公开(公告)号：US09797241B2

公开(公告)日：2017-10-24

申请号：US14766421

申请日：2014-02-07

Applicant: XACT Downhole Telemetry Inc.

Inventor： John Godfrey McRory

IPC: E21B47/16 ,  E21B47/14 ,  B06B1/02

CPC classification number: E21B47/16 ,  B06B1/0215 ,  B06B2201/55 ,  B06B2201/73 ,  E21B47/14

Abstract: An acoustic transmitter for transmitting an acoustic signal through a downhole medium includes a voltage source; a composite load; and switching circuitry that applies voltage from the voltage source across the composite load in response to a drive signal. The composite load includes charge control circuitry, in the form of at least one inductor, connected electrically in series with a piezoelectric transducer that may be electrically modeled as a capacitor.