EROSION BUFFER MATERIAL Russian patent published in 2024 - IPC C09K8/40 E21B33/138 

FIELD: cementing of oil and gas wells.

SUBSTANCE: invention relates to buffer fluids. Erosion buffer material contains anionic surfactant, superplasticizer, binding component, 0.5–0.7 wt.% of fresh or reservoir water with water-mixture ratio of 0.5–0.7 and a lightening mineral additive. Superplasticizer used is 0.5–1.0 wt.% of powder product based on modified ether of polycarboxylic acids Melflux® SELECT 5691 F, as a binding component—15.0–20.0 wt.% of water-soluble powder of aluminum hydroxochloride, as a lightening mineral additive—79.0–84.5 wt.% of expanded clay dust with specific surface area of 450–550 m²/kg. As anionic surfactant it contains 0.02–0.05 wt.% of sodium salt of sulphonated linear hydrocarbon Tainolin AOS-97P. Water and Tainolin AOS-97P are added in excess of 100%.

EFFECT: high-quality preparation of annular and annular spaces of cemented casing strings for replacement with grouting solutions in conditions of negative, low and normal temperatures due to use of sedimentation-resistant erosion washing liquid formed during hydration of erosion buffer material, capable of breaking loose part of filtration crusts on walls of wells and films of drilling fluids on casing strings at different speeds of movement of composite columns of solutions during cementing of casing strings and thereby provide an increase in the adhesive properties of the backfill stones.

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