The Design And Implementation Of High-Performance Ultrasonic Reflection Logging Instrument

Ultrasonic reflection logging is a classic method, there are a lot of application in current oil and gas exploration. With the increase of the difficulty of solving geological problems, ultrasonic instrument requires higher performance, main features:increase the dynamic range and improve the accuracy; compensate the attenuation of ultrasonic wave from well fluid automatically to meet the logging requirements of different proportion of mud; enhance the level of integration further to adapt to different well radius; further reduce the power consumption, and improve the temperature characteristics of the instrument; combine ultrasonic TV and ultrasonic detection of cementing quality into one instrument to improve the work efficiency.According to these requirements, this paper based on the principle of ultrasonic reflection, discusses the basic method of ultrasonic reflection of borehole image and cementing quality inspection, carried out experimental studies of the ultrasonic echo signal with different wave impedance, different proportion of mud, provides the basis for the design of instrument. On this basis, demonstrates the design scheme of ultrasonic reflection logging instrument. Focusing on the requirements of high-performance, use the latest levels of military or automotive integrated electronic devices, design the new ultrasonic excitation circuit and the module of ultrasonic attenuation conpensation, and choose higher integrated A/D quantizer with the greater dynamic range, use the low voltage power supply as far as possible. Through the above scheme and measures, the instrument will be with higher integration, lower power consumption, better temperature performance, more precise data recording, more adaptable to different proportion of well diameter. After development, debugging and experiment, results show that, the instrument can meet expected design requirements.The main innovation of this paper lies in:in view of the high power consumption of high vlotage narrow pulse ultrasonic excitation circuit,large volume, and the frequency offset caused by temperature in conventional ultrasonic reflection wireline logging, design the new ultrasonic excitation circuits based on CMOS integrated switch, meet the requirements of low power consumption, high efficiency, small volume, stable performance; focusing on the problem of ultrasonic attenuation, design the voltage controlled gain amplifier, compensate the attenuation of ultrasonic echo signal in the mud, to improve the accuracy and reliability of the echo arrival time detection; combine the ultrasonic TV imaging logging instrument and ultrasonic cementing quality detection instrument into one, to make a set of apparatus which can be used for not only borehole television imaging but also evaluating the first interface cementing quality by obtaining the full wave echo information.In summary, the study of this paper solves several key problems of ultrasonic reflection logging instrument at present, the result has important practical value to improve the performance of the instrument and engineering application.