A high temperature retarder HTR-300L applied in long cementing interval

Abstract

With regard to slow development or super retarding happening at the top of cement slurry in deep and ultra-deep wells with long cementing intervals, a new type of retarder HTR-300L was developed and its properties were evaluated. Thickening property tests at different temperatures for slurries with HTR-300L and IR, DSC and TG analysis show that: HTR-300L has good temperature-resistance performance and stable molecular structure. It can be used at the bottom hole circulating temperature of 70 to 200 °C. The thickening time of the slurry can be regulated effectively by adjusting the additive amount of HTR-300L. Thickening property tests for slurries with different salt contents show that HTR-300L has good salt-resistance performance and can be used in salty cement slurry. Strength development, thickening time, fluidity and API filtration of slurries with HTR-300L were studied at different top-bottom temperature differences. The results show that: The slurry with HTR-300L develops well in strength at large temperature difference and can overcome super retarding of the top of the slurry in long cementing interval. HTR-300L is applicable for large temperature range and can be used for slurries with both high and low densities. The slurry with HTR-300L has good overall performance, easy to regulate and control, and can satisfy cementing requirements for long cementing interval. Key words: retarder, cementing, long cementing interval, slurry, thickening time