Study Of Ultrasonic Flow Measurement Technique

In the process of exploiting oil and gas field, real-time flow measurement has animportant significance for improving the production efficiency and safety. Ultrasonic flowmeasurement technology is very suitable for applications in oil and gas field because of theadvantages of non-contact, high-precision, low-cost and so on. It is a pity that this technologycan’t fully meet the requirement of field-test currently, as a result of the uncertainty of the fluidingredients and the complexity of test environmental affect the measurement accuracyseriously.The research content of this paper is the ultrasonic flow measurement technology, andemphatically analyses the measurement principle, accuracy, temperature characteristics,applicability of the time difference method and Doppler method. Based on this, it determinesthe selection principle of ultrasonic flow measurement method in corresponding conditions,combined with the measurement environment and measuring fluid characteristics of oilproduction process in the drilling, injection well, production well.Through a lot of theoretical analysis, Doppler method ultrasonic flow measuring has thewider application in oilfield, so the flow meter we developed uses ultrasound Doppler flowmeasurement technology. This paper finishes the design and realization of software andhardware of the flow meter. The hardware circuit includes an ultrasonic signal transmittingcircuit, receiving circuit, a demodulation circuit, amplifier circuit, filter circuit, data storageand transmission circuit, and the circuit structure chooses the high performance, low noisedevice in order to improve the anti-interference ability of the circuit. Its data acquisition anddata processing functions are finished by the high performance DSP device TMS320F2812,which uses the12bit A/D converter for data acquisition, and data processing involves themain content including the frequency spectrum analysis, flow calculation, meanwhile DSPdevice also completed some other functions like DDS driver, data storage and transfer.Making a lot of simulating test in laboratory, it shows that the system of the ultrasonicDoppler flow meter works stabile, its accuracy can meet the design requirements, which is the reliable foundation for usi ng extensively in oil field.