Addition of tartaric acid to prevent delayed setting of oil-well cement containing retarder at high temperatures

Abstract

The setting time of the cement containing retarder at high temperature is longer than that at low temperature, which is an abnormal phenomenon and is adverse to the safety of cementing operation. Several kinds of retarders were chosen to demonstrate the abnormal phenomenon and to select the retarder with the ability to eliminate the abnormal phenomenon. Tartaric acid was found to be the only retarder which did not show the abnormal phenomenon. Moreover, it could eliminate the abnormal phenomenon of the cement containing a copolymer retarder. In addition, tartaric acid may also eliminate the abnormal phenomenon in cement containing other retarders, and it may be used with other retarders together to develop a compound retarder without the phenomenon of slow setting at high temperature. The elimination mechanism of the abnormal phenomenon was studied by comparing the hydration products of the cement containing AMPS-IA with the cement containing tartaric acid using XRD. Based on the results, there was a reduction in the hydration rate difference of tetra calcium aluminoferrite (C4AF) between low and high temperatures after introducing tartaric acid, which could be the reason why tartaric acid could eliminate the abnormal phenomenon.