VISCOELASTIC COMPOSITION FOR INSULATING FLOW OF STRATAL WATER INTO WELLS (VERSIONS) Russian patent published in 2009 - IPC E21B33/138 

FIELD: chemistry.

SUBSTANCE: invention relates to oil and gas industry, specifically to viscoelastic compositions for insulating flow of stratal water into wells in hydrogen sulphide deposits. The viscoelastic composition for insulating flow of stratal water into wells contains the following in wt %: water soluble polymer - polyvinyl alcohol 5.0-6.8, gel formation initiator - basic copper (II) carbonate 1.0-1.9, complexing agent - aqueous ammonia solution with concentration of 25% 3.8-5.9, water - the rest. In the second version the viscoelastic composition contains, wt %: polyvinyl alcohol 5.0-6.8, basic copper (II) carbonate 1.0-1.9, complexing agent - monoethanolamine 1.0-2.5, water - the rest. In the third version the viscoelastic composition contains, wt %: polyvinyl alcohol 5.0-6.8, basic copper (II) carbonate 1.0-1.9, complexing agent - a mixture of ammonium sulphate and natural gas liquid NGL-10 or NGL-11 1.4-4.6, water - the rest, where pts. wt ratio of ammonium sulphate to NGL-10 or NGL-11 is 1: 0.4-2.5 respectively. In the fourth version the viscoelastic composition contains, wt %: polyvinyl alcohol 5.0-6.8, basic copper (II) carbonate 1.0-1.9, complexing agent - mixture of ammonium sulphate and sodium hydroxide 1.5-5.4, water - the rest, where pts. wt ratio of ammonium sulphate to sodium hydroxide is 1:0.6-2.8 respectively.

EFFECT: improved technological and insulation properties of the viscoelastic composition due to regulated gel time, improved strength properties and resistance to hydrogen sulphide aggression, wider assortment of gel formation initiators, reduced consumption of ingredients.

8 cl, 3 tbl, 1 ex