Sonic Logging Tool Design System

With the development of modern technology, there is more and more demand for oil. It is generally known that oil is a non-renewable energy, and its storage capacity will be less and less, therefore the requirements of the logging instrument are higher and higher. Due to the particularity of the downhole environment, there are many special requirements in the well logging system. The main work of this paper is to study and design for downhole equipment, it consists mainly about electronic circuit module, transducer module and CAN transfer bus module. The design of each module need to consult project indicators in order to achieve improve the performance of the whole instrument as well as reliability and low power consumption. Finally we applied them to actual oil exploration and to improve oil drilling efficiency, to achieve the purpose of saving energy.According to the requirement of the logging instrument in high temperature and high pressure environment and the principle of the reliability and low power consumption, we do a lot of work on the detailed designs of the electronic circuit and acoustic wave transducer, and make many simulation and experimental tests for the performance of the system.The main work of this paper is as follows:(1) According to the actual requirements of acoustic logging, we confirm that acoustic wave transmitting transducer use radial polarized ring transducer and test the frequency characteristic of transmitting transducer, and receiving transducer use mosaic structure tangential polarized transducer, the transducer has six negative poles and six positive poles, and they are isolative by material. It has been proved that the transmitting and receiving transducer meet the requirements of the acoustic velocity logging.(2) According to the systematic design requirements, we divided the function circuit into transmitting circuit, receiving circuit and transport module. The transmitting circuit includes power supply of the whole circuit and the signal generation circuit which can produce a20kHz rectangular impulse wave. Because the signal of the receiving terminal is very weak, therefore the receiving circuit includes amplification and filtering, then the signal is converted to digital signal by analog to digital converter. The main role of the transport module is implementing the data transmission between down hole and ground part, and the transmission mode is CAN transfer bus.(3) We use simulation software NI MultisimlO to accomplish simulation and analysis, and perfect the design of circuit system according to the result. Finally we accomplish the excogitation of acoustic velocity logging system and the full test.