CO_2吞吐效果的影响因素分析

ANALYSIS OF MAJOR INFLUENCING FACTORS ON EFFICIENCY OF CO_2 HUFF AND PUFF

由于CO2 与原油接触时要求的混相压力低 ,且CO2 能使原油的粘度降低和体积膨胀 ,因而成为注气采油中优先选用的气体。影响CO2 吞吐效果的因素很多 ,通过对CO2 吞吐机理的研究 ,结合室内实验和矿场分析 ,综合考察了油层孔隙介质和油层流体的性质、原油中胶质与沥青质的含量、自由气含量、实验压力、施工中流体的配伍性等因素对CO2 吞吐效果的影响。结果表明 ,原油中胶质、沥青质的含量越高 ,吞吐效果越差 ;压力降低导致的CO2 脱气可降低油的产量。

CO 2 is preferred gas with the advantages of relatively lower minimum miscibility pressure when CO 2 contacts reservoir oil, which makes viscosity of oil reduced and oil swelled. There are a number of influential factors on CO 2 huff and puff efficiency. On the basis of mechanism of CO 2 huff and puff, some experiments in laboratory and analysis on observation data from CO 2 huff and puff project of oilfield, some affecting factors on CO 2 huff and puff, such as the properties of porous media and liquids in reservoir, the contents of asphalts and asphaltenes, the content of free CO 2, the compatibility of operational liquids and experimental pressure, are studied comprehensively. The results indicate that the efficiency of CO 2 huff and puff gets poor with the increase in the contents of asphalts and asphaltenes, and the free CO 2 caused by reduction in pressure leads to the decrease in oil production, which makes the permeabilities of cores reduced.