Synthesis and Performance of High Temperature Filter Loss Reducer ZFA-1 for Oil Well Cement Slurries

Water-soluble polymers have limited temperature resistance in high pH environment. To improve the high temperature performance of filter loss reducers, a new high temperature filter loss reducer, ZFA-1, was developed using a quite different way of synthesis than conventional way of synthesizing water-soluble copolymers. ZFA-1 is an inorganic non-metallic material compounded with organic polymer. The optimum synthesis conditions was determined as follow through experiment:molar ratio of AM:IA:AMPS=6.0:2.5:1.5, the concentration of molecular weight modifier=0.005%, concentration of coupling agent=0.5%, concentration of inorganic material=5%, concentration of initiator=0.5%, mass fraction of monomers=25%, pH of the reaction system=6, initiation temperature=55℃, and the reaction time=6 h. Characterization of the synthesis product with FT-IR and DSC/DTG showed that the product obtained had the molecular structure as expected. The ratio of weight loss of ZFA-1 at 326℃ was only 7.81%, which can be credited to the introduction of coupling agent and inorganic material that improve the high temperature stability of the final product ZFA-1. Laboratory evaluation of ZFA-1 showed that at concentrations of 1.0% -1.5%, the filtration rate of cement slurries can be controlled within 50 mL at 93-200℃ and 6.9 MPa. ZFA-1 has excellent salt-resistance and no negative effect on the compressive strength of set cement.