COMPACTING SPACER FLUIDS AND METHODS FOR USE THEREOF Russian patent published in 2017 - IPC C09K8/40 E21B33/138 

FIELD: mining.

SUBSTANCE: group of inventions relates to use of spacers in underground formations. Method of displacing drilling mud, arranged in annular space of well shaft, includes development of spacer fluid to comply with at least one property in predefined conditions of well shaft, where property is selected from a group consisting of: yield point from approximately 25 to approximately 250 Pa, static shear stress of gel from approximately 70 lb-force/100 feet² (137 Pa) to approximately 500 lb-force/100 feet² (978 Pa), yield strength at compression of about 1 psi (7 kPa) to about 2,000 psi (13,790 kPa) and unlimited strength at monoaxial compression from approximately 5 psi (34 kPa) to about 10,000 psi (68,950 kPa); use of spacer fluid to displace at least part of drilling fluid from annular space of well shaft; enabling least part of spacer fluid to consolidate in well shaft, and where part of spacer fluid is compacted in well bore to comply with determined property.

EFFECT: high efficiency of displacement of fluid in well shaft with spacer fluid before adding another liquid, improved removal of solid substances, separation of physically incompatible fluids.

73 cl, 2 dwg, 8 tbl, 11 ex