微乳酸的缓蚀行为及其在岩心中的酸化效果

The Corrosion Inhibition Behavior of Microemulsified Acid and Its Acidizing Effect in Core

采用盐容忍度较宽（0～120g／L）的微乳酸（O／W）体系，考察N80钢片、岩心砂分别在土酸及土酸微乳液中的化学反应，研究这2种不同的酸液体系在填砂管中的渗流、化学反应特征以及在天然岩心中的酸化效果。实验结果表明，该微乳酸对钢片、岩心砂的腐蚀（溶蚀）速度分别约是土酸的55％及60％；微乳酸在填砂管中的损耗速度也小于土酸体系。在50cm填砂管中，当注入速度为0．5mL／min，注入量为30mL时，土酸主要作用在注入端至20cm处，微乳酸在距注入端13cm处开始反应。在天然岩心中，土酸作用后注入端面变得疏松，而微乳酸作用后流出端面变得疏松。

Experiments were conducted in an O/W microemulsified acid system with a wide salinity tolerance range（0 ～ 120 g/L）. For comparison, the chemical reactions of the N80 steel and the sand particles in two acid systems, including mud acid and microemulsified acid, were studied. The different characteristics of the chemical reactions in unconsolidated sand packs of the two acid systems were observed as well as their acidizing effects in cores. After microemulsification of the mud acid, its corrosion rates to the N80 steel and the sand particles were found to decrease by 45% and 40% respectively compared with that of mud acid, and lower loss rates in unconsolidated sand packs were observed. In an unconsolidated sand pack with a length of 50 cm, when injected at a rate of 0.5 mL/min for 60 min, the mud acid reacted at the distance of 0 ～ 20 cm, and the microemulsified acid at the 13～50 cm. In core flooding, the end face near the outlet became loose with microemulsified acid; however, the inlet end face became loose with mud acid. Because of the excellent corrosion inhibition performance after emulsification, the microemulsified mud acid system can flow to reservoir＇ deep parts and be reliably applied to indepth reservoir acidizing.