火烧油层(干式燃烧)室内实验研究

Lab experimental study on in situ combustion(dry combustion)

在现场火驱开发过程中,火烧状态很难判定,为解决这一难题,对火驱采油机理进行了室内模拟研究。使用冷37-45-562井天然油砂,开展一维模型火烧油层物理实验,分析了在火烧过程中产出气体和火烧前后原油组成的变化特征。实验结果表明:CO2、CO浓度变化规律反映了原油从被点燃到形成稳定燃烧区的过程,其浓度变化的第1个峰值对应原油自燃温度。运用色谱、色质、红外等分析手段,结合相关化学反应机理,证实了在火烧过程中原油经历低温氧化、高温裂解和高温氧化的过程。其研究方法和结论可为现场火驱动态监测提供依据。

The combustion situation is difficult to determine during in situ combustion process in oil fields,so lab simulations are conducted to study the mechanism of in situ combustion.The experiments were conducted with a one-dimensional physical model and natural oil sands from Well Leng37-45-562 to analyze the characteristics of the change in the gas produced from the combustion process and the oil compositions before and after combustion.The experimental results indicate that the change pattern of CO2 and CO concentration reflects the process from the ignition of the oil to the stage when the stable combustion has developed in an area and the first peak of the concentration change corresponds to the self-ignition temperature of the oil.Using the analysis methods of the chromatography,chromatograph mas spectrometer and infrared as well as the related chemical reaction mechanism,it has been confirmed that the crude oil has experienced low temperature oxidization,high temperature pyrolysis and high temperature oxidization during in situ combustion process.The research method and conclusions in this paper can provide a basis for monitoring the performance of the in situ combustion in oil fields.