D Esign And Implementation Of Optical Fiber Probe System Under Oil Well Based On DSP

In recent years,with the rapid development of optical fiber technology,optical fiber sensor has become a very important measurement device.From the measurement principle,because the three-phase flow of oil gas water involves three different kinds of media,changes in multiple refraction will in which light travels,this change can sensitively reflect changes in dielectric properties,which makes the measurement gas rate possible.Moreover,the optical fiber sensing technology has the advantages of high insulation,anti electromagnetic interference and good insulation,and is especially suitable for the complicated and changeable conditions in the process of oil field exploitation.In addition,the optical fiber has the advantages of small size and light weight.For these reasons,the optical fiber measurement has become an excellent scheme for measuring the gas content in the oil gas water three-phase flow.The main research work of this paper is as follows:First of all,according to the actual measurement of the downhole measurement tube,a gas sensor with four optical fiber probe is designed.In this paper,a new denoising method based on wavelet transform is proposed to deal with the interference in the process of optical fiber probe measurement.In this paper,an adaptive weighted calculation method is proposed for the estimation of the measurement results of a single fiber probe.Secondly,on the basis of the four optical fiber probe,the hardware circuit design and software flow chart are designed.In the aspect of hardware design,DSP is selected as the core processor,respectively,completed the design of pretreatment circuit,control circuit,memory circuit,transmission circuit,communication circuit,power supply circuit;in the aspect of software design,the detailed design process of software AD module,memory module,calculation module is given.Finally,the experimental study on gas holdup measurement of oil well is carried out.Firstly,the experimental logging environment is constructed,and the three-phase fluid in the well is simulated according to a certain proportion.Secondly,the three group experiment,oil flow in three-phase flow is set to 1.5m~3/d in the first set of experiments,the flow of water is8.5m~3/d,water flow total 10m~3/d;the second set of experiments,the oil flow in the three phase flow is set to 22.5m~3/d,the water flow is set to 7.5m~3/d,a total of 30m~3/d water flow.The process and results of the three sets of experiments confirmed the validity of the method for measuring the gas holdup.