二甲醚赋能稠油热采的SAGD技术开发规律模拟研究OA

Dimethyl ether-assisted steam-assisted gravity drainage(DME-SAGD)technology demonstrates significant potential for enhancing heavy oil recovery.This study developed a numerical model to comprehensively characterize DME-SAGD technology.The model revealed the critical mechanisms of DME in improving heavy oil mobilization efficiency and recovery,alongside an optimized injection parameter strategy.The experimental data were fitted based on the control equation and the PR equation of state,and heavy oil and DME fluid models,as well as their interaction model,were constructed.A 3D reservoir model was also established based on geological parameters.Numerical simulations systematically compared SAGD and DME-SAGD technologies in terms of steam chamber development,heavy oil mobilization efficiency,and production dynamics.At the same time,a detailed study was conducted on the dynamic evolution process of DME-SAGD,including the characteristics of temperature field expansion,the distribution characteristics of DME,the movement trajectories of gas-phase fluids,the changes in oil saturation,and the variation patterns of heavy oil viscosity.Ultimately,the injection concentration,injection method,and injection timing of DME were optimized through sensitivity analysis.The results indicate that DME accumulates at the steam chamber's top and edges,enhancing pressure transmission and facilitating both vertical and lateral steam chamber expansion.Its superior heat and mass transfer capabilities maximize thermal efficiency,delay steam condensation,and reduce heat loss.DME's high solubility in the oil phase enhances miscibility with heavy oil,further reducing viscosity,accelerating oil production,and increasing recovery,thus achieving efficient development of heavy oil.Compared to conventional SAGD,DME-SAGD improves cumulative oil production by 26.3%and recovery by 14.57%.Optimization studies have shown that the optimal injection conditions are as follows:The injection mole fraction is 3%;the injection method is mixed injection with steam,and the injection timing is during the lateral expansion stage of the steam chamber.This achieves the best development effect and economic benefits.