非酸解堵技术在渤海油田的应用

针对渤海油田疏松砂岩储层常规酸化易导致储层岩石骨架破坏，且受管柱结构和修井作业的限制残酸无法及时返排产生二次沉淀，同时高电导率的返排液无法直接进入处理流程，严重制约酸化工艺现场应用等问题，研究出一种兼顾油层解堵和油层保护，且具备较低残液电导率的非酸解堵体系。该体系主要含有20%复合多羧基螯合剂A及5%含氟络合物C，缓慢释放出H+、F-，体系pH值在6~7之间，具有高效缓速性，同时有效保护岩石骨架，通过螯合金属离子达到阻垢抑垢、减少二次沉淀的效果，且具有较低的腐蚀性，返排液具备较低的离子浓度及电导率，可实现返排残酸直接进入平台流程就地、高效地处理。该体系在渤海油田进行了现场试验，效果显著，具有良好的应用前景。 

Application of Non-acid Block Removing Technology in Bohai Oilfield

A non-acid block removing fluid has been developed to deal with several problems encountered in the development of unconsolidated sandstone reservoirs in Bohai oilfield. The problems include failure of rock matrices in conventional acidizing job, secondary precipitation caused by residue acids that are unable to timely flow back because of the limits from configuration of pipe string and workover jobs, and flowback fluids with high electric conductivity that cannot be directly disposed of. All these problems pose serious restrictions on reservoir acidizing operations. The newly developed non-acid block removing fluid is also able to protect the reservoir from being damaged. The residue of this non-acid block removing fluid has lower electric conductivity. The non-acid block removing fluid, containing 20% compound polycarboxylic chelating agent A and 5% fluorine complex C, can slowly release H+ and F-, and maintain its pH value between 6 and 7, showing high retarding property and capability of protecting rock matrices. By chelating metallic ions, scales are prohibited and secondary precipitation is minimized. The non-acid block removing fluid has low corrosivity, and the flowback fluid has low ionic concentrations and electric conductivity, which are beneficial to the on-the-spot and efficient disposal of the flowback residue acid in the platform process. This non-acid block removing fluid has been tried out in Bohai oilfield with remarkable efficiency, showing good application prospect.