METHOD FOR WELL CASING WITH RESERVOIR PROPERTIES RETENTION IN PRODUCTIVE BED Russian patent published in 2006 - IPC E21B33/138 

FIELD: well building, particularly to retain reservoir properties of productive bed during well protection against contaminating and clogging action of filtrate.

SUBSTANCE: well casing method involves lowering production string in well; washing-out clay coating with buffer liquid; creating protective shield made as impervious cement coating of chemical agent modified cement mortar, wherein polyvinyl acetate reagent taken in amount of 0.25-0.5% by weight of cement mass is used as the chemical agent for cement modification. Above modification is performed by solving polyvinyl acetate reagent in water during mixing water preparation with the use of antifoaming agent taken in amount of 10% by volume of polyvinyl acetate reagent mass. The chemical agent modified cement mortar is injected in portions. After the first portion injection ordinary cement mortar is supplied. At the end of injection operation the modified cement mortar portion is injected to separate productive section beds. At the end of well casing operation the first portion of modified cement mortar is forced to day surface.

EFFECT: possibility to retain reservoir properties of the bed, increased technological effectiveness of well casing material preparation and usage.

2 cl, 1 tbl, 2 dwg