稠化剂提高低渗油藏CO2驱油效果适应性评价OA北大核心CSTPCD

During CO2 flooding,viscous fingering is prone to occur,which severely limits the effectiveness of CO2 flooding.To address this issue,an experiment for evaluating the viscosity increasing performance of a linear block copolymer thickener on CO2 and its control effect on CO2 channeling of heterogeneous cores was carried out.A quantitative method was established to evaluate the control and regu-lation effect of the thickener on CO2 viscosity and core heterogeneity,the mechanism of the thickener improving CO2 oil displacement ef-ficiency was analyzed,and the effect of the thickener increasing CO2 oil displacement efficiency in low permeability reservoirs is simula-ted using a three-dimensional radial flow model.The experimental results show that,under reservoir conditions,the thickening agent can increase the viscosity of CO2 by 18 times;Injecting thickening agent-CO2 system 1.0 PV into two types of low permeability heterogene-ous cores with the permeability difference of 5 and 10,and then performing CO2 flooding,can increase the CO2 flooding efficiency of the cores by 13.75 and 11.98 percentage points,respectively;The main mechanism of the thickener improving CO2 flooding efficiency in low permeability reservoirs is to increase CO2 viscosity,which contributes 79.6％and 72.5％to improving the oil displacement effi-ciency of two types of heterogeneous cores,respectively;The method of using thickeners to improve CO2 flooding efficiency has good a-daptability to low permeability reservoirs.