油气地质与采收率2025，Vol.32Issue(3)：78-87,10.DOI:10.13673/j.pgre.202412030
裂缝型白云岩和灰岩储层酸蚀机理差异性数值模拟研究
Numerical simulation study on differences in acid dissolution mechanisms between fractured dolomite and limestone reservoirs
摘要
Abstract
The fractures often alter the acid dissolution patterns and affect the acid treatment effectiveness during acid treatments in fractured carbonate reservoirs.Based on the two-scale continuum model,scholars have conducted numerous studies on the acid dissolution mechanisms in porous and fractured carbonate reservoirs using numerical simulation methods.However,relatively few studies focused on the differences in how fractures influence the acid dissolution mechanisms in fractured dolomite and limestone reservoirs.The two-scale continuum model was extended,and an acid dissolution model suitable for simulating acid treatment in carbonate reservoirs with varying calcite and dolomite contents was developed.Then,the related research was conducted in conjunction with a pseudo-fracture model.Acid dissolution simulation results for dolomite and limestone reservoirs were obtained by changing the positions,lengths,and dip angles of fractures.The acid treatment effectiveness was evaluated using the acid dissolution patterns and breakthrough volumes,clarifying the influence of fractures on the acid dissolution mechanisms in dolomite and limestone reservoirs.This provided a theoretical foundation for the design and optimization of acid treatments in fractured dolomite and limestone reservoirs.The results indicate that the optimal acid pump rates for limestone reservoirs are higher than those for dolomite reservoirs.When the pump rates are lower than the optimal ones for dolomite reservoirs,the breakthrough volumes of the two reservoirs are similar.However,when the pump rates exceed the optimal ones for dolomite reservoirs,the breakthrough volumes in dolomite reservoirs remain consistently higher than in limestone reservoirs.The primary factor influencing breakthrough volume is fracture length,while the secondary factor is fracture dip angle.As fracture length increases and dip angle decreases,the breakthrough volumes decrease in dolomite and limestone reservoirs,whereas fracture position has little effect on breakthrough volume.Short fractures have a greater impact on dolomite reservoirs than on limestone reservoirs,but as fracture length increases,their influence on both reservoir types becomes more similar.In dolomite and limestone reservoirs,fractures at different positions,with various lengths and dip angles,attract acid flow,and wormholes consistently connect the fractures.Compared to acid-etched wormholes,the amounts of acid dissolution on the fracture walls are minimal.The influence of fracture dip angles on acid dissolution patterns is mainly reflected in the directions of the main wormholes.Fractures facilitate rapid acid breakthrough;few branches develop on the fracture walls when the fracture dip angles are small.However,fractures hinder rapid acid breakthrough,and numerous branches develop along the fracture walls as the fracture dip angle increases to 75° in dolomite reservoirs and 60° in limestone reservoirs.关键词
裂缝型储层/白云岩储层/灰岩储层/酸化/裂缝长度/裂缝倾角/酸蚀模式Key words
fractured reservoir/dolomite reservoir/limestone reservoir/acid treatment/fracture length/fracture dip angle/acid dis-solution pattern分类
石油、天然气工程引用本文复制引用
齐宁,苏徐航,李雪松,张鹏,路依鑫,周顺明..裂缝型白云岩和灰岩储层酸蚀机理差异性数值模拟研究[J].油气地质与采收率,2025,32(3):78-87,10.基金项目
"十三五"国家科技重大专项"碳酸盐岩复合深度改造优化设计方法及配套技术研究"(2017ZX05030005-002-003),山东省自然科学基金项目"深层碳酸盐岩酸压酸蚀裂缝导流能力演化规律研究"(ZR2024ME106),中国石油大学(华东)研究生创新基金项目(中央高校基本科研业务费专项资金资助)"缝洞型矿物非均质碳酸盐岩储层酸压技术研究"(24CX04041A). （2017ZX05030005-002-003）
