CO_2驱替过程中沥青质沉积及其对原油采收率的影响

Asphaltene deposition and its impact on oil recovery during CO_2 flooding

针对CO2驱油过程中易造成沥青质等重有机质沉积,导致原油组分发生改变,影响驱油效果这一问题,考察了不同原油沥青质含量、岩心渗透率条件下沥青质的沉积量及CO2驱油效果,研究了CO2驱替过程中沥青质沉积和原油采收率的变化规律。实验结果表明,CO2驱油过程中引起的沥青质沉积与岩心渗透率、原油初始沥青质含量直接相关;相同条件下,低渗透岩心对沥青质沉积的影响更为明显;此外,随着沥青质沉积量的增加,CO2驱的采收率降低。

CO2 flooding tends to have asphaltene deposition problem,resulting in the change of oil components and affecting oil displacement result.This paper investigates the asphaltene content of different crude oils,the volume of asphaltene deposition under certain core permeability conditions as well as relevant CO2 flooding effects.The relationship between asphaltene deposition and oil recovery factor in CO2 flooding has been studied.The results of experimental study indicate that asphaltene deposition in CO2 flooding process is directly related to core permeability and initial asphaltene content of crude oil;under the same conditions,core permeability is more influential to asphaltene deposition;moreover,with the increasing of asphaltene deposition,the recovery factor of CO2 flooding decreases.