PARTICLES CONTAINING WASHING MEDIUM FOR WELL CLEANING Russian patent published in 2015 - IPC C09K8/52 E21B37/06 

FIELD: oil-and-gas industry.

SUBSTANCE: inventions group relates to oil and gas industry. Fluid washing medium for deposits removal from walls of the underground drilled well includes liquid carrier with viscosity close to the water viscosity, and able for pumping along the well wall under turbulent flow mode, and a disperse component dispersed in the liquid carrier and containing spherical particles with size at least 100 micron and density from 0.8 to 1.3 g/cm³; at that the disperse component occupies 1-10% by volume of the fluid. Method of deposits removal from wall of the drilled well includes a stage, when the above mentioned fluid is injected above wall of the drilled well such that a turbulent flow is created in at least deposits zone.

EFFECT: improved annulus cleaning before cement solutions injection or during completion, abrasive cleaning of all soft materials present in annulus, in particular gel-like clay mass and clay cake without use of the additional equipment and without metal parts damage.

10 cl, 5 dwg