摘要
在碳酸盐岩油藏酸化中,裸眼完井和射孔完井对酸蚀溶解形态特征的影响不同。酸液在裸眼完井的井筒中与岩石接触面积远大于射孔完井,酸液受地层非均质性的影响选择性地进入地层,这与射孔完井时酸液针对性地进入地层不同,有必要对不同完井方式的酸蚀溶解形态进行研究。通过一种达西–孔隙双重尺度模型,创新性地利用正态分布函数生成模拟区域初始孔隙度值,研究了射孔完井对酸蚀溶解形态的影响,并分析了孔眼沿程滤失的影响。结果表明:由于射孔在孔眼区产生局部高导流能力的通道,酸液通过孔眼进入地层,溶解形态与裸眼完井不同,且射孔越短蚓孔分支越多,射孔越长蚓孔分支越少;同一注入速度下,孔眼沿程无滤失的突破体积最小,裸眼完井的突破体积最大;完井方式和滤失对蚓孔形成的最优注入速度没有影响;当注入速度较小时,由于反应前缘与残酸前缘距离很小,在酸液临近突破时压力骤然下降,当注入速度较大时,由于反应前缘较宽,压降比较平缓。
In carbonate acidizing,different completion methods have different effects on dissolution patterns caused by acidiza-tion. In this paper,we use a normal distribution function to generate initial porosity values and a two-scale continuum model to study the effects of perforation completion on dissolution patterns and analyze the effect of leakoff along the aperture. The results show that the dissolution pattern is very different from that of openhole completion. Acid flows into the formation through perforation tunnel,and the number of wormhole branches increases with the decrease of perforation length. Under the same injection velocity,the breakthrough volume of perforation completion without leakoff along the aperture is the least and that of open-hole completion is the most. Completion and leakoff rarely have effects on the optimum injection velocity. At small injection velocity,the inlet pressure declines sharply in the termination regime because of a very small distance between reaction front and spent acid front;at large injection velocity,the inlet pressure declines slowly due to the wide reaction front.
出处
《西南石油大学学报(自然科学版)》
CAS
CSCD
北大核心
2014年第6期117-122,共6页
Journal of Southwest Petroleum University(Science & Technology Edition)
基金
国家科技重大专项(2008ZX05017–003–02–01HZ)
国家自然科学基金(51274213)
关键词
完井方式
碳酸盐岩
蚓孔扩展
溶解形态
滤失
completion
carbonate
wormhole propagation
dissolution pattern
leakoff