METHOD TO DRILL WELLS ON SELF-SACRIFICING FOAM ALONG CLOSED CIRCULATION CYCLE, PLANT AND COMPOSITION OF SELF-SACRIFICING FOAM FOR ITS REALISATION Russian patent published in 2013 - IPC E21B7/00 E21B21/14 C09K8/38 

FIELD: mining.

SUBSTANCE: method includes circulation of a system of drilling mud and efficient quantity of a foaming composition, made of a foaming agent and a stabilising polymer, addition of a gaseous agent into a liquid with speed sufficient to form a foam drilling mud and removal of the foamed drilling mud from a well. Drilling is carried out on the self-sacrificing foam, which is supplied into a well along the closed circulation cycle by means of pumping through a plant for circulation and regeneration of the self-sacrificing foam by means of injection of the self-sacrificing foam into a drilling string, direction of the flow of the self-sacrificing foam with rock sludge after evacuation from the well along the chute system into a sump for regeneration, soaking in the sump until self-sacrificing, return to the stage of addition of the gaseous agent for repeated foaming and return into the well. The foaming composition is a composition of the self-sacrificing foam on the basis of carbamide resins, previously modified with ammonia chloride, sulfanol, second group metal chlorides and water.

EFFECT: invention provides for high indices of technical characteristics of foam, such as half-life and expansion ratio of foam, and also stability and resistance of foam, improved environmental condition around a well, reduced prime cost of works.

10 cl, 4 dwg, 9 tbl