白云岩酸蚀蚓孔模拟实验与分析

Simulation experiment and analysis of acid wormhole in dolomite

关键词:  白云岩  酸化  稠化酸  蚓孔  实验

Key words:  dolomite  acidizing  thickening acid  acid wormhole  experiment

摘要:

酸蚀蚓孔能大大改善低渗透白云岩储层渗流条件、提高酸化增产效果,而蚓孔发育条件是关系到该类储层酸化施工中酸液体系和施工参数优化的关键问题。采用稠化酸和盐酸进行了缓蚀性能实验对比;针对低渗白云岩储层天然裂缝发育的特征,采用人工剖缝方式模拟天然裂缝中酸液流动反应特征,实验分析了注酸排量、酸液粘度、温度以及用酸量对蚓孔发育的影响。实验结果表明:稠化酸较高的粘度有利于增加酸液有效作用距离和酸蚀蚓孔的扩展;酸岩反应温度过高,限制了酸化施工对地层渗透率的改善效果;酸液用量存在最优值,过多的酸量注入只会造成浪费。

Abstract:

Acid wormhole can greatly improve the flow conditions of dolomite reservoir and increase the effect of acidizing stimulation,while the wormhole development is the key issue related to the optimization of acid system and construction parameters for this type of formation.This article compares the corrosion inhibition property of thickening acid with hydrochloric through experiment;aiming at the characteristics of natural fractures of dolomite reservoir,artificial fracture is made to simulate the flow and reaction feature in natural fracture,and the impact of acid injection flowrate,acid viscosity,temperature and acid amount on acid wormhole development is analyzed.The results show that the higher viscosity of thickening acid helps to increase the effective reaction distance and the expansion of acid wormhole;high reaction temperature limits the acidizing effect of improving formation permeability;there is an optimal value of acid volume,the excess amount of acid injection will only result in the waste of acid.