长岩心酸化流动试验对优化砂岩酸化设计的作用

EFFECT OF LONG-CORE ACID FLOW TESTING ON OPTIMIZATION OF SANDSTONE ACIDIZING DESIGN

以往研究砂岩基质酸化最常用的方法是短岩心酸化流动试验，本文提供了一种长岩心酸化流动试验研究新方法。长岩心酸化流动试验结果表明：采用前置盐酸和低浓度氢氟酸有利于提高酸化效果，残酸离子分析证实高温地层酸化极易形成Si（OH）4沉淀。但短岩心酸化流动试验结果为：加大酸液浓度和用酸强度有利于提高酸化效果。对比短岩心和长岩心酸化流动试验结果表明：只有模拟就地条件下的长岩心酸化流动试验才能更好地优选酸液体系，达到优化酸化设计的目的，经现场应用取得显著效果。

Acid core flow testing,which core is typically short core plugs, is a common method forstudying sandstone acidization. In this study, The long core plug is used in acid core flow testing. Theflow testing results with long core show that the pad chlorhydric acid and lower concentration fluorhydric acid are useful to improve acidization effectiveness. Analysis of spent acid indicates that the settingof hydrated silica will be produced during acidizing under high temperature conditions. However,according to short core acid flow testing,higher concentration acid is helpful to increasing permeability. Comparing the testing results of long core and short core, the conclusion has been obtained that acidizing design based only on short core studies is misleading. This paper also gives an introduction to the effectiveness of sandstone acidizing based on long core acid flowing testing by several field examples.