Circuit Design Of Ultrasonic Image Logging Tool For Small Radius Boreholes

In the relevant techniques of coal mine coalbed methane mining and gas emissions,they often match small size drill combinations.Slim hole can not only significantly reduce the cost of exploitation,but also the only way for ultradeep drilling.Development of slim hole technology requires related supporting tools to promote,and various small-size logging instruments are more indispensable.Ultrasonic imaging logging tool use reflected ultrasonic echo as an information carrier,which can be used to detect holes,cracks and lithology of the open hole and can also be used to detect the casing deformation of the Cased well,cementing quality,etc.It is an important research area of coming logging tool.Advanced logging while drilling technology have been monopolized by strong logging companies in foreign countries,while domestic related research is still in its infancy.In the field of coal mine safety production,it is urgent for slim hole to develop Logging While Drilling tools.Therefore,the ultrasonic imaging logging while drilling technique which applied to slim hole is proposed.From the basic principles of ultrasonic imaging,the main components of ultrasonic imaging logging instruments at home and abroad are investigated,select high-efficiency small-size circuit system programs,and finally design a circuit structure of ultrasonic logging instrument suitable for slim hole,which its outer diameter is as low as 89 mm.The article will focus on a series of key technologies in designed circuit system,mainly including the following three aspects: Firstly,on the basis of analyzing the material and excitation principle of the ultrasonic transducer,a simple and reliable high voltage power supply(50v)scheme is finally screened by comparing multiple programs.Secondly,choosing the driver of ultrasonic transducer high pressure pulse.The article research and refer design ideas of other companies and research institutes in the industry,ultimately select a pair of complementary high-speed(60MHz),high pressure(200V),low resistance value(8?)MOS tube switch as a key control chip.Thirdly,analyzing the characteristics of ultrasonic echo signal,designing appropriate signal conditioning scheme,mainly including signal limit,amplification,wave filtering,differential transmission,etc.The ultrasonic echo signal is saved completely and without distortion.Finally,the article designed a set of ultrasonic imaging log circuit system based on STM32H750 was designed,stimulated 250 k Hz Piezoelectric ultrasonic transducer got the clear ultrasonic echo data of the envelope and met the actual logging requirements of coal mine drilling.It have the meaning of engineering application.