OIL BASED DRILLING FLUID AND COPOLYMER BASED ON STYRENE, LAURYL METHACRYLATE AND (METH)ACRYLIC ACID - Patent 1185598

(19)

(11)

EP 1 185 598 A1

(12)

(43)	Date of publication:
	13.03.2002 Bulletin 2002/11

(21)	Application number: 00943770.8

(22)	Date of filing: 06.06.2000

(51)	International Patent Classification (IPC)⁷: C09K 7/06, E21B 21/00, E21B 37/06, E21B 33/138, C08F 212/08, C08F 220/18

(86)	International application number:
	PCT/EP0005/174

(87)	International publication number:
	WO 0078/891 (28.12.2000 Gazette 2000/52)

(84)	Designated Contracting States:
	AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
	Designated Extension States:
	AL LT LV MK RO SI

(30)

Priority:

22.06.1999 GB 9914400

(71)	Applicant: Ciba Specialty Chemicals Water Treatments Limited
	Bradford,West Yorkshire BD12 0JZ (GB)

(72)	Inventors:
	Hey, Susan Margaret BradfordWest Yorkshire BD10 8LJ (GB) Dungworth, Howard Roger NorlandHalifax HX6 3QZ (GB)

(54)	OIL BASED DRILLING FLUID AND COPOLYMER BASED ON STYRENE, LAURYL METHACRYLATE AND (METH)ACRYLIC ACID