“酸敏”砂岩储层的酸化适用性探讨

酸化压裂技术在鄂尔多斯盆地长庆气区部分特低渗透砂岩储层改造中取得了一定的效果，但对于该工艺在酸敏储层的适用性存在争议。酸敏评价实验标准中所用酸液类型及浓度并不是针对具体储层特征的最佳优化结果，因此该类实验得出的敏感性结论并不能作为储层是否可采用酸化处理的依据。为此，开展了酸液岩心流动评价实验，通过研究储层的损害类型和分析储层中矿物含量，进而优化出了酸化工作液体系，形成了以有机酸为主的酸液体系。岩心实验结果表明，该酸化工作液对酸敏砂岩储层进行酸化是适用的，可有效地提高酸化效果。

Adaptability of acidizing to acid-sensitive sandstone reservoirs

Certain good results have been achieved in the stimulation of ultra-low permeability sandstone reservoirs through acidizing and fracturing treatment in the Changqing gas zone,Ordos Basin,however,its adaptability to the acid-sensitive reservoirs is in dispute among researchers.The types and concentration of the acid liquids used in the acid sensitivity evaluation experiment criteria are not the best option for those reservoirs with specific characteristics,so the results from this experiment can not be regarded as good reference for the operators to decide if acidizing treatment will be good for the reservoirs.In view of this,the experiment of core flow of acid liquids is conducted.Through the studies of formation damage types and the analysis of mineral contents in formation,an acidizing fluid system is then developed with the organic acid being dominated.The experiment shows that this working fluid is adaptable to the acid-sensitive sandstone reservoirs and can improve the efficiency of acidizing treatment.The acidizing and fracturing treatment is a good stimulation measure for the ultra-low permeability sandstone reservoirs.