Stduy On The Kinetics Of Barium Sulfate Scale In Oilfield Water Injection Pipeline Systems

Pipeline scaling caused by baium sulfate is one of the serious problems during oilfield flooding process, is effected by the variation of pressure, temperature and thermodynamic instability. Due to the complicacy of scaling process, current experimental study always focuses on hermodynamic analysis. Therefore, it is of significant importance to study barium sulphate scaling kinetics in terms of preventing potential hazard.The measure in methods of the concentration of barium in solution are investigated in this paper.First, baium sulfate particles can solve thoroughly by means of adding DTPA (chelating agent) and adjusting pH value to12. Then lame atomic absorption spectrometry can be used to measure the barium concentration. The standard curve of concentration obtained by this method with the higher sensitivity and accuracy.Secondly the concentration-conductivity equation obtained by the conductivity measurement of barium chloride, sodium sulfate, sodium chloride solution in different concentration and temperature. A series of experiments are carried out in order to measure the variation of conductivity immediately. Nucleation induction period and different stages of particle growth are confirmed by means of analyzing conducctivity curves. Furthermore, the macro kinetic equations of barium sulfate crystallization can be aquired.Additionally, simulation instrument is constructed based on the study of barium sulfate scaling process of oilfield water injection system: The flame atomic absorption method and differential pressure method is used to measure the deposition behavior of barium sulfate during reaction process in capillary tube. The effects of the pipeline length, reaction liquid pipe flow, inlet concentration and temperature on the deposition process is investigated. According to the profound research of dynamics mechanism through deposition coefficient and kinetic coefficient, model of deposition process, which is consistent with the real experimental data, can be aquired and the results can be verified by the corresponding SEM images.