Cement retardant and its application

Abstract

The present invention belongs to the field of cement technology, and is especially one kind of cement retardant and its application. The cement retardant is prepared with 2-acrylamido -2-methyl propyl sulfonic acid 20-50 wt%, itaconic acid 30-70 wt% and sodium hypophoshorate 10-20 wt%, and through mixing to react while adding water in 180-230 wt% and ammonium persulfate in 0.5-4 wt% at 65-92 deg.c for 1-4 hr. The cement retardant is added into cement mortar and used at circulation temperature lower than 95 deg.c to prolong the thickening time of cement mortar effectively.

Description

technical field

[0001] The invention belongs to the technical field of well cementing, in particular to a well cementing retarder and its application. Background technique

[0002] In oil and gas well cementing operations and other underground cementing operations, it is usually required to inject cement slurry containing cement, water and admixtures into the predetermined formation underground through surface pumping equipment to seal the annulus between the formation and the casing. . Typically cement slurry is pumped into the casing and returns to the annulus through the gap between the casing and the formation. The cement slurry solidifies in the annular space to form a hard cement sheath column, which can form a bond with the formation and the casing. In order to achieve a satisfactory cementing operation, it is necessary to achieve a high-strength bond to prevent fluid channeling along or within the cement sheath, which would contaminat...