适用于碳酸盐岩储层的固体酸解堵体系

传统的液体酸解堵体系，多使用盐酸、硝酸等常规液体酸。在存放、运输和使用过程中，液体酸存在设备成本高和安全风险大的问题。选用氨基磺酸、柠檬酸、二乙基三胺五乙酸为基础，对这3种不同类型固体酸的溶蚀性能、稳定铁离子能力进行性能评价。利用复配实验，调控3种固体酸的比例，确定最优的复配固体酸配方为m（氨基磺酸）∶m（柠檬酸）∶m（二乙基三胺五乙酸）为8∶1∶1。以此复配固体酸为主剂，加入缓蚀剂、渗透剂、黏土防膨剂构建得到固体酸解堵体系。该固体解堵体系具有较好的溶蚀碳酸钙能力，对大理石的溶蚀率达到27.65%，良好的稳定铁离子的能力，络合铁离子容量达到643.71 mg/L。通过岩心流动实验表明，该固体酸解堵体系的注入体积达到10 PV时，可以提高岩心渗透率20%以上。现场利用固体酸体系施工后，施工井产量较高。 

A Solid Acid Block Removing System for Carbonate Reservoirs

Conventional acid block removing systems generally are formulated with common liquid acids such as hydrochloric acid or nitric acid. These liquid acids have high costs and safety risks in storing, transportation and operation. To solve these problems, three solid acids, which are sulfamic acid, citric acid and diethyl triamine penta-acetic acid, are selected to study their dissolution capacity and capability of stabilizing iron ions. By adjusting the ratio of the three acids, the optimum ratio was determined to be∶m(sulfamic acid)∶m(citric acid)∶m(diethyl triamine penta-acetic acid) = 8∶1∶1. A solid acid block removing system was formulated using the compound solid acid as the main additive, coupled with corrosion inhibitor, penetrant and clay swelling inhibitor. This solid acid block removing system has the ability to dissolve calcium carbonate; a percent rate of dissolution of 27.65% of marble was obtained with the solid acid block removing system. The solid acid block removing system has iron ion complex capacity of 643.71 mg/L, a good iron ion stabilizing performance. Core flow experimental results showed that when the solid acid block removing system was injected into the core by 10 PV, the permeability of the core was increased by at least 20%. Field operation has shown that the application of this solid acid block removing system resulted in higher production rate of hydrocarbons.