METHOD OF SELECTIVE INSULATION OF FLUID ENTRY Russian patent published in 2009 - IPC E21B33/138 

FIELD: oil and gas production.

SUBSTANCE: invention refers to methods for insulating fluid entry in oil, gas and oil-gas wells and can be implemented in oil and gas producing industry. The method of selective insulation of fluid entry consists in successive pumping of pressurisation fluid, preliminary spacer fluid, a backfilling composition, successive spacer fluid and pushing fluid into a reservoir; also backfilling composition contains a clayish component, sodium silicate and fresh water; as pressurising and pushing fluid there is used reservoir water, while as spacer fluid there is used fresh water at amount of not more, than 1 m³ for preliminary pumping and not more, than 0.5 m³ for successive pumping; crushed claydite is used as a clayish component and additionally there are used sodium fluorsilicate, sodium carbonate and surface active substance SAS at the following ratio of components, wt %: crushed claydite 17.5-22.5; sodium silicate 45-60; sodium fluorsilicate 4.5-5.5; sodium carbonate 1-3; SAS 0.001-0.005, fresh water - the rest; notably claydite is crushed to a fraction less 0.4 mm.

EFFECT: upgraded efficiency of fluid entry insulation due to improved structure-mechanical properties of backfilling composition.

2 cl, 4 tbl