不返排绿色可降解酸的研制与性能评价

针对目前常规酸液环境不友好、酸化后需及时返排等问题,在考察乳酸、葡萄糖酸溶蚀能力、谷氨酸N,N-二乙酸GLDA的螯合容量以及优选添加剂的基础上,确定了绿色可降解酸液体系配方:20%乳酸+葡萄糖酸(摩尔比1∶1)+1.5%谷氨酸N,N-二乙酸GLDA+2%缓蚀剂HLS-1+1%铁离子稳定剂CA-1+2%黏土稳定剂COP-2,研究了该体系的溶蚀性能、缓蚀性能、可降解能力及对储层的伤害性。研究表明:绿色可降解酸液体系具有较好的缓蚀、缓速及螯合性能,对岩心伤害率低,不会产生二次沉淀,无酸渣,残酸稳定。该体系的溶蚀反应速率常数为3.37×10^-7(mol/L)^-m/(cm²·s),是常规稠化盐酸的0.1倍,在酸化过程中生成了溶解度较大的乳酸葡萄糖酸钙,红外光谱分析进一步证明了酸液的可降解性。该酸液具备不返排酸化的性能特点,有助于降低酸化施工成本和实现绿色环保作业。图14表6参10

Development and Performance Evaluation of Nonflowback Green Degradable Acids

In view of the current problems of unfriendly environment of conventional acid solution and the need for timely backflow after acidification,based on the investigation of corrosion performance of lactate and gluconic acid,chelation capacity of glutamic acid N,N-diacetate GLDA,and the optimization of of additives,the formulation of green acid dissolving solution system was determined as follows,20%lactate+gluconic acid(molar ratio 1∶1)+1.5%GLDA+2%inhibitor HLS-1+1%iron ion stabilizer CA-1+2%clay stabilizer COP-2.The corrosion performance,corrosion inhibition,degradability and damage to reservoir of the system were investigated.The results showed that the system had good corrosion inhibition,inhibition rate and chelation performance,and the system had low damage rate to core,no secondary precipitation,no acid residue,stable residual acid.The corrosion reaction rate constant of the system was 3.37×10-7(mol/L)-m/(cm2·s),which was 0.1 times of that of the conventional thickened hydrochloric acid.The reaction product was calcium lactate gluconate with high solubility in the process of acidification.Infrared spectrum analysis further proved the degradability of the acid solution.The acid solution had the characteristics of nonflowback acidification,which is helpful to reduce the cost of acidification construction and realize green environmental operation.