The Casing Pressure Testing System Design Based On Pipeline Structure Filter

The casing pressure testing system is an important test before casing application. It can avoid or reduce that the oilfield casing leakage accident happens. However, It can generate intense pressure fluctuation in the whole pipeline system that hydraulic test pump operates with high speed in the process of high pressure test. It can make the casing pressure measurement data far away from the accurate enough. The amplitude frequency characteristics of the specific structure pipelines are studied to filter out the pressure fluctuations in the pipeline. It can make the higher value to actual engineering and scientific research.In this paper, the fluctuation situation of continuous pressure wave in the pipeline is analyzed by starting from the fluctuation phenomenon of fluid in the pipeline on the basis of theory about fluid fluctuation transient. The mathematical model that is used to describe the transmission of continuous pressure wave in the pipeline is established. The distribution situations of the pressure and the flow along the pipeline on time can be clearly described by the model. The influence of various factors about pipeline and fluid on the fluctuation can be represented by using the transfer function and impedance in this paper. The fluctuation can be affected by the different terminal impedance. The frequency and amplitude characteristics of the single horizontal pipeline and the horizontal pipeline with filter are respectively analyzed.The attenuation situation of continuous pressure wave with different frequency in the single horizontal pipeline is shown in the form of model simulation. The attenuation situation of fluctuation in a frequency range is also shown after the use of the filter. Filtering experiments are also done by using the real fluid. The frequency and amplitude characteristics of the horizontal pipeline with filter and the single horizontal pipeline are verified according to the experiment data of pressure collection.The horizontal pipeline with filter is used in the casing pressure testing system. The corresponding measuring and showing device is designed. The pressure fluctuation in the pipeline is monitored to get the real-time data. It can be shown that the violent fluctuation is changed to the moderate fluctuation with the filter by the experimental data. It can be shown that the specific frequency fluctuation can be filtered by using the filter in these experiments.The error can effectively reduced by using this kind of filter in the casing pressure testing system.