砂岩油藏注水井脉冲式在线注入酸化增注技术

注水是实现油田长期稳产和高效开发的关键技术。受储层物性及注入水水质等因素的影响，华庆油田部分区块注水压力逐渐上升，高压欠注井越来越多，而目前现有的酸化增注技术暴露出有效期短、多次酸化增注低效、措施占井周期长、设备动迁困难、作业成本攀升等问题。针对以上问题，结合目标区块储层特征，通过大量室内实验调试对比，将常规六齿氨基羧酸螯合剂配位键升到八位，形成八齿螯合剂，增强了对金属离子的捕获、螯合、包裹作用，通过酸液复配，优选出一种适合目标储层的酸液体系；与此同时加强设备优化改进，添加远程操作系统，提高精准度；通过地面配套脉冲式柱塞泵注程序，形成了注水井脉冲式在线注入酸化增注技术。截至目前现场应用4井次，措施后平均单井注水压力下降9.0 MPa，单井日增注14.0 m3，平均有效期已达182 d，降压增注效果显著，有效期长；同时该技术解决了占井周期长、设备动迁困难等问题，现场操作简便，建议推广应用。 

Pulsed Online Acidizing Augmented Injection to Sandstone Reservoirs

Water injection is a key technique for long and efficient development of oil. In recent years, more and more wells in some blocks of the Huaqing oilfield are faced with increasing injection pressure resulted from the physical properties of the reservoir and the quality of injected water. Presently increasing injection rate is done by acidizing, but there are several challenges for this technique, for example, the time for this technique to work effectively is short, the injection efficiency is low after many times of acidizing, the execution of the technique lasts a too long, the equipment required for executing the technique is difficult to move, and finally, the operation cost is not acceptable. In laboratory study, a lot of experiments have been done to resolve these problems based on the study on the characteristics of the reservoirs in Huaqing. It was fount that by changing the commonly used hexadentate amino carboxylic acid chelating agent to octadentate chelating agent, the ability of the chelating agent to capture, chelate and wrap metal ions is enhanced. By mixing the chelating agent and acid, a new acid suitable for acidizing job was formulated. Meanwhile, the equipment used for water injection was also improved and optimized. A long-distance operational system was added to the equipment to improve the accuracy of the operation. Using a surface pulsed piston pump, a pulsed online acidizing augmented injection technology was formed. This technology has till now been applied 4 times, water injection pressure was reduced by an average of 9.0 MPa, volume of water injected per day per well was increased by 14.0 m3, and the average time for the stimulation measure to remain effective was 182 d. Other problems previously met, such as long time of operation, difficulty in moving the equipment required etc. have all been resolved. It is worth spreading this new and easy technology in water injection job.