MUD FILM-FORMING AGENT FOR DRILLING MUD AND DRILLING MUD USING THE SAME

摘要

PROBLEM TO BE SOLVED: To prepare a drilling mud simply by using a material present at a job site without requiring a material for preparing a mud such as bentonite, CMC or a polymer agent. SOLUTION: This mud film-forming agent for the drilling mud comprises (x) a copolymer containing (a) an unsaturated carboxylic acid and/or its salt and (b) a monoester of (b1) an unsaturated carboxylic acid and (b2) a hydroxy group-containing compound represented by the general formula R(OA)nOH (R denotes hydrogen or a 1-12C hydrocarbon group; A denotes a 2-4C alkylene group; and n denotes an integer of 1-100) as constituent units.