SYNTHETIC FILTRATION REDUCER Russian patent published in 2021 - IPC C09K8/487 

FIELD: oil industry.

SUBSTANCE: group of inventions relates to synthetic filtration reducers and can be used in the oil and gas industry in the construction of wells. Synthetic filtration reducing agent for use as an additive to cement mortars for drilling wells contains a copolymer of 2-acrylamide-2-methylpropyl sulfonic acid (AMPS) with a mass fraction of 5-90%, N-methylolacrylamide with a mass fraction of 5-80% and methacrylic acid with a mass fraction of 5-80%. The method for synthesis of the above-mentioned filtration reducer includes supplying water to the reaction tank using a pump and heating to 60-70°C, introducing AMPS, N-methylolacrylamide and methacrylic acid into the mixing tank, heating with stirring to 60-70°C through the jacket coil using a coolant, pumping the resulting solution from the mixing tank into the reaction tank using a pump, purging the reaction mixture with nitrogen at atmospheric pressure to remove air oxygen from the tank to an oxygen content of no more than 0.6%, introduction of potassium persulfate with stirring and maintaining a temperature of 60-70°C for 120 minutes, unloading the reaction mass using a screw pump into an intermediate storage tank, feeding the reaction mass into roller dryers, cutting a thin film of the dried product with a knife, grinding dry powdery material to obtain a dry synthetic filtration step-down. The hydrogen pH of the solution is maintained at the pH level of 6-10 by adding calcium hydroxide.

EFFECT: increase in the filtration characteristics of cement mixtures to improve the quality of well cementing, reduce the risks of cracks and overflows, reduce the filtration crust and increase the flow rate of the well.

3 cl, 1 tbl, 6 ex