三元复合驱注入井共轭酸解堵增注体系

由于三元复合驱中聚合物、碱的存在，易形成“胶团”状混合物，使注入井堵塞，常规化学解堵技术解堵半径小、有效期短，容易产生二次沉淀且需要返排残酸，大幅增加了措施成本及安全环保隐患。为了解决措施有效期短及残酸返排不环保的问题，研发了三元复合驱注入井共轭酸解堵增注体系。通过扫描电镜及CT三维数字岩心重构，明确了堵塞物的微观形貌及结构特征；通过无机质溶垢及离子络合评价实验，研发出一种共轭酸解堵增注体系。实验结果表明，三元复合驱注入井堵塞物是由聚合物、垢质、蜡胶质形成的多元“团状”聚集体；共轭酸解堵增注体系可实现深部解堵，无二次沉淀；岩心渗透率的恢复率较常规解堵剂提高29.2%，平均措施有效期193 d，措施后无需返排，实现了三元复合驱注入井解堵措施的高效环保。

Plug removal and injection stimulation system with conjugate acid in ASP injection wells

Due to the presence of polymers and alkalis in ASP flooding, it is easy to form a micelle-like mixture, which will block the injection well. The conventional chemical plug removal technology has a small effective radius and a short period of validity, it is easy to generate secondary precipitation, and the residual acid need to flow back, which greatly increases the cost of stimulations and the hidden dangers to environment. In order to solve the problems of short validity period of stimulations and the dangers of residual acid to environment when flows back, the plug removal and injection stimulation system with conjugate acid in ASP injection wells was studied. The microscopic morphology and structural characteristics of the plugs were clarified by scanning electron microscopy and CT 3D reconstruction. Through the evaluation experiments on inorganic scale dissolution and ion complexation, a plug removal and injection stimulation system with conjugated acid was developed. The experiment results show that the plugs in the ASP injection wells are multi-component clump-like aggregates formed by polymers, scales, and wax colloids. The plug removal and injection stimulation system with conjugated acid can realize deep plug removal without secondary precipitation. Compared with conventional plug removal agent, the recovery rate of core permeability after using this system was increased by 29.2%, with an average validity period of 193 days. After stimulation, there is no need for residual acid to flow back, which realizes the high efficiency and environment protection during plug removal process in ASP injection wells.