Research On On-line Testing Technology Of Drilling Fluid Density And Solid Content Based On Ultrasonic

Drilling fluid plays a pivotal role throughout the entire drilling process.Density and solid content are two important parameters to measure the performance of drilling fluid,which constantly affect drilling quality and oilfield protection.As drilling operations continue,the density and solid content of drilling fluid can change with the impact of formation properties and the formation environment.Therefore,real-time detection of drilling fluid density and solid content is very important,and is a prerequisite for on-site implementation of drilling fluid allocation and ensuring safe and high-quality drilling,It is of great significance to carry out research on online detection technology for drilling fluid density and solid content.Based on consulting relevant information on ultrasonic testing technology,this paper discusses the basic characteristic parameters and related testing principles of ultrasonic waves,analyzes the propagation and attenuation characteristics of ultrasonic waves in drilling fluid,as well as the structure and working mechanism of ultrasonic transducers.By establishing the internal relationship between drilling fluid density and sound velocity,solid content,and ultrasonic attenuation,an online testing scheme for drilling fluid density and solid content is developed.According to the established detection scheme,using STM32F407ZET6 chip as the main control chip,using a pulse transformer and MOS transistors to convert the DC 24 V signal into an AC signal,the design of the ultrasonic transducer drive circuit is completed;In order to accurately collect the echo signal by the chip,an echo signal processing circuit composed of an amplitude limiting circuit,a filtering circuit,and an amplification circuit is designed;According to the nature of drilling fluid,the selection of electromagnetic valves has been completed,and relevant driving circuits have been designed.Combined with a liquid level sensor,drilling fluid can automatically flow in and out;The data transmission adopts RS232 serial interface,and the detection results are displayed through the LCD12864 module.Through the power circuit design,the entire detection system is powered.Finally,according to the overall circuit schematic diagram,the PCB board is designed and fabricated,and the hardware design of the entire detection system is completed.Based on the hardware design,the universal timer of STM32F407VET6 chip is used as a master slave timer to transmit a certain frequency and a certain number of PWM pulse signals to drive the ultrasonic transducer;In order to accurately obtain the ultrasonic transmission time and the maximum amplitude of the echo signal,the ultrasonic transmission time program and the maximum characteristic wave search program have been developed;Displaying the detected temperature and detection results on the LCD screen through a temperature acquisition program and a LCD display program;The communication of the detection system is realized using RS232 program,and the software design of the detection system is completed.Finally,an experimental platform is built through the designed detection system to carry out experimental research.Take drilling fluid density of 1.12(g/cm3),1.36(g/cm3),1.53(g/cm3),1.71(g/cm3)and 1.89(g/cm3)respectively;The solid content is 5%,10%,15%,20% and 25%,and the transmission experiment is carried out under the ultrasonic probe with the center frequency of 1MHz and 2MHz.The inverse algorithm is used to establish the relationship between the ultrasonic sound velocity,echo amplitude and the density of drilling fluid and the solid content,and the effect of temperature on the sound velocity and amplitude in the ultrasonic transmission process is considered.According to the fitted expression,the density and solid content of drilling fluid are detected by detecting the sound velocity and echo amplitude.