| Sand production in production wells is one of the inevitable universal problems in the process of oil and natural gas production.Sand production within a reasonable range is inevitable,but explosive or excessive sand production will cause equipment damage and oil wells stop production.On-line monitoring technology for sand production in oil and gas wells can be intuitionist and can reflect downhole sand production in real time.It has been paid more and more attention by more and more researchers.It is a frontier research topic at home and abroad in recent years.In this paper,the on-line monitoring technology of sand production wells is studied.The main tasks are as follows:(1)on the basis of analyzing the characteristics of vibration signals produced by sand particles impacting the bend of wellhead,a theoretical model of sand production monitoring in gas wells is established.(2)according to the spectrum and propagation characteristics of sand production signals,the performance parameters of sand production monitoring sensors are optimized,and a reasonable acoustic wedge structure is designed.The sand-producing monitoring sensor with complete function has been developed,and tested and verified,which has achieved good results.(3)Analyzed the flow characteristics of sand carrying in gas wells.Combined with the pipeline structure,the FLUENT software was used to simulate the pressure field of the pipeline,and the optimal installation position of the sand monitoring sensor was determined.(4)The field programmable gate array Field Programmable Gate array(FPGA)is used as the core.The signal output of the sensor is adjusted and collected by using the ultra-high speed A / D conversion chip and signal amplifying and filtering circuits.The dual channel 16 bit ultra high speed data acquisition is realized.The noise caused by pipeline vibration and fluid flow is eliminated and the sand output signal is extracted from the noise.The effectiveness of sand production signal processing is verified by experiments and the monitoring prototype of sand production signal is formed.(5)The software of upper computer is developed.On the basis of processing such as filtering and amplifying in hardware circuit,the received sensor signal is further filtered and de-noised by LabVIEW software,and the instantaneous sand output is calculated by using the established theoretical model.The results of quantitative calculation are given.The on-line monitoring data can be observed in real time and stored,and the historical data can be replayed at the same time.On the basis of the above work,a large number of experiments have been carried out on the whole set of systems developed and calibrated indoors to verify the accuracy and validity of the measurement. |
