【摘要】 二氧化碳在油藏中的波及范围是评价致密油藏二氧化碳吞吐采收率的关键参数。如何计算吞吐过程中二氧化碳的波及范围已成为新的研究热点。基于二氧化碳对流扩散机理,建立二氧化碳吞吐的理论模型,通过Laplace变换方法得到理论模型的解析解,绘制二氧化碳浓度分布图版,形成一种合理计算吞吐过程中二氧化碳波及范围的新方法。在此基础上,定义二氧化碳极限作用浓度,提出二氧化碳有效作用半径的概念,并分析弥散度、分子扩散系数和注入速度对有效作用半径的影响。研究结果表明:影响致密油藏二氧化碳吞吐有效作用半径的主要因素是注入速度和分子扩散系数,弥散度对有效作用半径的影响较小。更多还原

【Abstract】 The sweep scope of carbon dioxide is a key parameter to improve the recovery of carbon dioxide huff and puff in tight oil reservoirs. It has become a new research hot spot to calculate the sweep scope of carbon dioxide in the process of huff and puff. Based on the mechanism of carbon dioxide convection diffusion, a theoretical model of carbon dioxide huff and puff was established. An analytical solution of the theoretical model was obtained by the Laplace transform method, and a carbon dioxide concentration distribution chart was drawn to form a new method to reasonably calculate the carbon dioxide sweep scope in the process of huff and puff. Based on this, the limit action concentration of carbon dioxide was defined, the concept of effective action radius of carbon dioxide was proposed, and the influence of dispersion, molecular diffusion coefficient and injection rate on the effective action radius was analyzed. The results show that the main factors affecting the effective action radius of carbon dioxide huff and puff in tight oil reservoirs are the injection rate and the molecular diffusion coefficient, and the dispersion has a small effect on the effective action radius.更多还原