Research Of The Measurement System For The Location Of The Water-oil-air Interface And Oil Thickness

After a period of rest of the different density fluid in the container, the density of the fluid will be effected according to the size form obvious stratification. Such as air-oil-water mixture are placed in the container, the cross section of the water, oil, gas interface can be clearly observed. Measure water interface location of oil and gas is one of the means of calculating reservoir volume or volume, in the petrochemical industry, sewage treatment, metallurgical casting, paper making, food production and other industries have a strong demand.The CCD is one kind of commonly photoelectric sensor in the opto-electronic measuring system, and it is the first selection of light intensity measurement device. CCD has developed rapidly in recent years, and has been widely used in digital photography, astronomy, remote sensing and other fields. There are two kinds of CCD device, line and array. The linear can measre the light distribution in ilne and the array CCD can be used to measure images. According to the analysis of measurement requirements, this paper selects the linear CCD as photoelectric measuring element, the size of the pixels scale is up to 3648.In order to improve the measurement precision, the section of the water, oil and gas is enlarged by an optical system, and the section is clearly imaging on linear CCD. CCD image acquisition system converts the light intensity distribution to digital information, and transmitte it through USB2.0 interface to a PC for processing. To eliminate noise and smoothing data, this paper uses the Savitzky- Golay filter to filtering the noise, the smooth data points within the window is given by the least-square fitting smooth numerical data points. The S- G filter for the discrete data curve fitting has the advantage of the polynomial convolution method, this algorithm reduced the requirement of computer memory and data processing capacity, reduced the time of data processing. Compare with the median method, average method, and the wavelet denoising, S- G filter processing effect is good, and improves the position judgment accuracy of the oil-water interface and the interface of oil and gas.This system software code is writeen with VC. This software has three parts, included by the hardware interface, man-machine interface and the developers. The hardware part responsible for the control of CCD data acquisition hardware and the communicate with acquisition card. Man-machine interface is responsible for the user interaction, and this software interface is practical, easy to operate. The oil-water interface sketch map is added to let the users have intuitive knowledge of reservoir location. Developement interface allows the users to develop software function independently, easy to function extension later. Savitzky- Golay filtering algorithm is added in the system sofrware. The position of the oil-water interface and the oil-gas interface is gotten after analysis the light intensity data, and then the oil thickness is calculated.Through the system accuracy test and system stability experiment, the design the oil-water interface and oil thickness measurement system is better realized the oil-water interface position measurement,this system has high reliability, high measurement precision, wide range of use, and easy to maintain, and can be used for the automatic measurement in the cases of flammable, explosive and other dangerous places.