| In recent years, the technology of high pressure air injection (HPAI) has attracted extensive attention worldwide.on the other hand, on the basic theory and application research of HPAI technology, there is still a lot of gaps and deficiencies. Compared with abroad, HPAI projects start late in China, and its basic theoretical research hasn’t been systematic yet. In addition, its oilfield practice is still in its infant stage. Therefore, it is necessary to expand related theory research.Therefore, in order to implement the project of HPAI successfully, and take control of the oxidation and autoignition process preferably, the research on oxidation andautoignition mechanism of light crude oil. Firstly, the paper summarizes the status of domestic and international theoretical research and application, selects t the property scope of light oil reservoir, which implements HPAI project, analyzes the weak link of oxidation and autoignition mechanism research, determine the study contents and methods of this article, and selects the representative light crude oil by comprehensive comparison to be use for experiment.First of all, the author uses oxidation tube experiment method to research the oxidation mechanism of light crude oil in the porous medium, and analyze a variety of factors effect on the oxidation behavior of light crude oil, such as temperature, pressure, clay mineral and oil sample. By comparing the oil phase and flue gas composition variation characteristics before and after oxidation of crude oil of oil, the paper deeply analyzes the mechanism of oxygen consumption, the oxidation and pyrolysis process and the pyrolysis reaction and combustion behavior of different origin light crude oils, assesses the variations in the combustion behavior of light crude oil, and rebuilds a new model of oxidation reaction and pyrolysis reaction of light crude oil. At the same time, in different reservoir condition, the autoignition potential of light crude oil were analyzed. Then, using thermal analysis method of Thermogravimetry/Derivative Thermogravimetry (TG/DTG) techniques and Differential ThermalAnalysis (DTA) technology, the light crude oils with joining different cuttings and components such as saturated alkane and colloid have been tested under different injection gas. The quality loss, the oxidation kinetics parameters and the degree of endothermic or exothermic of light crude oil have been studied by analogy analysis method. The paper analyzes their effect on oxidation properties to evaluate the potential of autoignition of light oil reservoir.On the basis of above study, the temperature of light crude oil in different reservoir environment has been traced by thermal monitoring instrument, which is our independent development instrument. Through analyzing the effect of reservoir temperature and the components of crude oil, the specific area of cutting and clay minerals on the changes of the oxidation temperature, the study finds that the oxidation temperature rise in the process of crude oil oxidation, and the temperature range is2～7℃.However, the autoignition, which is leaded by temperature rise, did not been detected under laboratory conditions. In this paper, using oxidation tube experiment and thermal analysis method had been done to study the effect of a variety of impact factors which make an impact on oxidation and autoignition of light crude oil in the process of HPAI, and using the thermal effect monitoring instrument to study on the phenomenon of whether autoignition occurred. Advances have been made in the study on the mechanism of oxidation and oxidation kinetics of light crude oil. All these will give beneficial references to related theoretical study and field application. |
PDF Full Text Request