Excitation circuit of transducer array of three-dimensional acoustic wave downhole instrument

Abstract

The invention provides an excitation circuit of a transducer array of a three-dimensional acoustic wave downhole instrument. The circuit comprises a plurality of sealed multi-channel high-voltage electronic units positioned in a transmission sonic system, and each multi-channel high-voltage electronic unit comprises a bus interface circuit, a command receiving and transmitting control circuit and a plurality of excitation channels, wherein the bus interface circuit is connected with a transmission master control electronic unit in the three-dimensional downhole instrument and used for receiving a control command sent by the transmission master control electronic unit; the command receiving and transmitting control circuit is connected with the bus interface circuit and used for decoding the received control command and generating a transmission control logic signal according to the received control command; and the plurality of excitation channels are connected between the command receiving and transmitting control circuit and the transmission transducer array in parallel and used for generating a driving signal to realize excitation of the transducer array. The excitation circuit disclosed by the invention can solve the connection between a three-dimensional acoustic logging excitation electronic system and the transmission transducer array under downhole high temperature and narrow space conditions and further solve the problem of a command interface with the transmission master control electronic unit.

Description

technical field [0001] The invention relates to an excitation circuit of a transducer array, in particular to an excitation circuit for a transducer array of a three-dimensional acoustic wave instrument in an oil well. Background technique [0002] Three-dimensional acoustic logging can more accurately describe the downhole formation in the radial, circumferential and axial directions, and the use of phased array acoustic emission and array receiving sensors with arbitrary directivity is the key technology to achieve three-dimensional detection capabilities . The phased array acoustic wave transmitting transducer unit used for three-dimensional acoustic logging is composed of multiple transducers (such as 8 transducers distributed at 45 degrees), and multiple sets of transmitting transducer units (3 or more), so that the energy of the acoustic radiation can be controlled in the circumferential and axial directions, thereby enhancing the useful signal and improving the signa...

AI Technical Summary

Problems solved by technology

Compared with the existing multi-pole acoustic instruments with more complex functions, the excitation circuit of the emission sound system of the three-dimensional acoustic logging will have the characteristic of multi-channel (such as 24-channel : 3x8) multiple emission excitation leads are required (such as 48: 24x2), and these leads transmit high-voltage signals (up to 500V or higher), which requires that the terminals of these leads need to withstand high voltage (greater than 100MPa) and It has good high-voltage insulation properties, which has not been realized in the field of petroleum logging technology today

[0003] At present, the maximum number of lead wires allowed for the pressure-bearing electrical connections between sub-joints of the acoustic logging instrument is less than 70, and when there are many lead wires, it is only used for the electrical connection of logic signals and acoustic wave receiving transducer array signals. At this time, there is no need to consider Insulation performance at high voltage, and the number of leads between the emission excitation circuit and the emission sound system is less than or equal to 32, so it is impossible to complete the connection between the three-dimensional emission transducer array and the emission electronic system according to the conventional method

At the same time, using a large number of long-distance connections to transmit high-voltage signals with a large instantaneous rate of change will inevitably introduce interference, which may cause errors in the downhole instrument system bus and local bus, and even cause serious damage to other circuits

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