Research on Fluid Loss Additives of AMPS/DMAM/AA in Well Cementing

In order to improve the temperature-resistance performance of some domestic fluid loss additives and to understand their poor compatibility with other additives as well as their comprehensive properties,a cement fluid loss additive was synthesized using monomers acrylic acid (AA),2-acrylamido-2-methyl-propane sulphonic acid (AMPS) and N,N-dimethyl acrylamide(DMAM)through aqueous solution polymerization.The micro-structural characterization of AMPS/DMAM/AA was analyzed and its performance was tested.The result showed that copolymer AMPS/DMAM/AA has the structure of all monomers and can resist high temperatures up to 380℃.When the amount of AMPS/DMAM/AA was more than 3.0 %,the filtration of fresh-water cement slurry can be reduced to less than 100 mL.Moreover,the cement slurry has excellent properties such as low initial consistency,short transition time,good thickening curve without far delayed solidification and appropriate compressible strength.When the amount of AMPS/DMAM/AA is more than 4.0 %,the filtration of saturated NaCl cement slurry can be reduced to less than 80 mL.It showed that the fluid loss additive AMPS/DMAM/AA has excellent temperature-resistance and salt-tolerance and good compatibility with other additives,especially with high temperature retarders.In addition,the cement slurry that has been prepared mainly from AMPS/DMAM/AA has excellent comprehensive properties.