METHOD FOR TREATING DRILLING FLUIDS TO IMPROVE THEIR MICROBIOLOGICAL STABILITY Russian patent published in 2022 - IPC C09K8/03 C09K8/35 C09K8/12 C09K8/24 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the field of drilling oil and gas wells. The drilling fluid treatment method to increase its microbiological stability includes the introduction of a bactericidal additive, which is an oxidizing biocide that dissociates in water to form hypochlorous acid. The specified biocide is introduced into the dispersion medium of the drilling fluid - water, kept for a disinfection time of at least 2 hours. The components provided by the formulation of the processed drilling fluid are added. After that, a hydrogen sulfide absorber is additionally added to the solution, a hydrogen ion concentration regulator is added - sodium and/or potassium hydroxide until the pH value of the solution reaches at least 9.5. Then the drilling fluid is treated with a biostat based on isothiazolinones. Processing reagents are taken in the following ratio, % to the mass of the drilling fluid: the specified biocide 0.03-0.06; hydrogen sulfide absorber 0.03-0.05; sodium and/or potassium hydroxide 0.03-0.1; biostat based on isothiazolinones 0.1-0.3. As an absorber of hydrogen sulfide, zinc oxide or iron oxide or carbonate is used.

EFFECT: increasing the stability of the rheological and filtration parameters of water-based drilling fluids by increasing the microbiological stability with a simultaneous increase in their inhibitory properties.

2 cl, 4 tbl, 2 ex