Associated copolymer and preparation method thereof, and drilling fluid

Patent metadata

Field	Value
Publication number	US-9719005-B2
Application number	US-201514970000-A
Country	US
Kind code	B2
Filing date	Dec 15, 2015
Priority date	Oct 21, 2015
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

Disclosed are an associated copolymer, a method for preparation of a polymer and a polymer prepared with the method, a use of the associated copolymer and/or the polymer in drilling fluids, and a drilling fluid containing the associated copolymer and/or the polymer. The associated copolymer comprises acrylamide structural units, zwitter-ionic structural units, and cationic polyamine structural units at a specific proportion, and the cationic polyamine structural units have specific kinematic viscosity and cationic degree; thus, when the associated copolymer is used as a viscosity improver for drilling fluids, the obtained drilling fluid not only has favorable apparent viscosity after it is aged at a high temperature, but also has high dynamic shear force, and is resistant to high temperature up to 200° C. or above, resistant to NaCl up to saturated concentration, and resistant to CaCl 2 up to 20 wt % concentration.

First claim

What is claimed is:

1. An associated copolymer, comprising a structural unit A, a structural unit B and a structural unit C, wherein the structural unit A is represented by formula (I):

wherein, R 1 , R 2 , and R 3 independently are H, substituted or unsubstituted C1-C5 alkyl;
wherein the structural unit B is a Zwitter-ionic structural unit; and the cation in the Zwitter-ionic structural unit is N + , and the anion in the Zwitter-ionic structural unit is SO 3 − ;
wherein the structural unit C is an ionic associate of the structural unit B and a cationic polyamine;
wherein, based on a total weight of the associated copolymer, a weight percentage of the structural units A is 10-75 wt %; a weight percentage of the structural unit B is 15-65 wt %; and a weight percentage of the cationic polyamine is 1-50 wt %;
wherein the structural unit C is at least one of structures represented by formulae (III-1), (III-2), and (III-3):

wherein, the dotted line represents ionic association; X − is an inorganic anion; R, R 9 , R 9 ′, R 10 and R 10 ′ independently are structures represented by formula (IV):

wherein, R 11 is H, substituted or unsubstituted C1-C5 alkyl, t is an integer within the range of 1-5, and z is an integer within the range of 0-5; n and p independently are an integer within the range of 1-5; x is an integer within the range of 0-10; y is an integer within the range of 1-10; values of I, I′ and I″ are such that a kinematic viscosity of the cationic polyamine is 100-500 mm 2 /s and a cationic degree of the cationic polyamine is 0.5-2 mmol/g.

2. The associated copolymer according to claim 1 , wherein the structural unit B is one or more of the structures represented by formulae (II-1), (II-2) and (II-3):

wherein, R 4 , R 4 ′, R 4 ″, R 4 ′″, R 5 ′ and R 8 independently are H, substituted or unsubstituted C1-C5 alkyl;
Z is O or NH; R 5 is C2-C5 alkylene or C6-C10 arylene; R 6 and R 7 independently are H, substituted or unsubstituted C1-C5 alkyl;

cycle is azacyclo bonded with (CH 2 ) m SO 3 − via a N atom;
m′ and m″ independently are 1 or 2 ; and
m is an integer within the range of 1-5.

3. The associated copolymer according to claim 2 , wherein the structural unit B is at least one of the structures represented by formulae (II-1-1), (II-2-1) and (II-3-1):

4. The associated copolymer according to claim 1 , wherein the kinematic viscosity of the cationic polyamine is 150-450 mm 2 /s and the cationic degree of the cationic polyamine is 0.5-1.5 mmol/g.

5. A method for preparation of an associated copolymer of claim 1 , comprising:
(1) copolymerizing a monomer a represented by formula (i) and a monomer b in an aqueous solution, with an inorganic salt in presence, to obtain a viscous intermediate product, wherein, the monomer b is a zwitter-ionic monomer; and the cation in the zwitter-ionic monomer is N + , and the anion in the zwitter-ionic monomer is SO 3 − ;
(2) contacting the viscous intermediate product obtained in step (1) with the monomer c, wherein the monomer c is cationic polyamine;

wherein, R 1 , R 2 , and R 3 independently are H, substituted or unsubstituted C1-C5 alkyl.

6. The method according to claim 5 , wherein the weight ratio of the monomer a to the inorganic salt is 1:(0.1-6).

7. The method according to claim 5 , wherein the inorganic salt is one or more of ammonium salt, calcium salt, magnesium salt, copper salt, zinc salt, aluminum salt, and zirconium salt.

8. The method according to claim 5 , wherein the inorganic salt is in the aqueous solution, and when the inorganic salt is an ammonium salt, the concentration of the inorganic salt solution is 10 wt %-30 wt %;
when the inorganic salt is a calcium salt, a magnesium salt, a copper salt or a zinc salt, the concentration of the inorganic salt solution is 5 wt %-15 wt %;
when the inorganic salt is an aluminum salt, the concentration of the inorganic salt solution is 2 wt %-10 wt %; and
when the inorganic salt is a zirconium salt, the concentration of the inorganic salt solution is 2 wt %-5 wt %.

9. The method according to claim 5 , wherein the copolymerization in step (1) is carried out under inert gas protection, and the conditions of the copolymerization include: copolymerization temperature being 40-60° C. and copolymerization time being 0.5-2 h.

10. The method according to claim 5 , wherein based on the total weight of the monomer a, monomer b and monomer c, the amount of the monomer a is 10-75 wt %, the amount of the monomer b is 15-65 wt %, and the amount of the monomer c is 1-50 wt %.

11. The method according to claim 5 , wherein the Zwitter-ionic monomer b is one or more of the structures represented by formulae (ii-1), (ii-2), and (ii-3):

wherein, R 4 , R 4 ′, R 4 ″, R 4 ′″, R 5 ′ and R 8 independently are H, substituted or unsubstituted C1-C5 alkyl;
Z is O or NH, R 5 is C2-C5 alkylene or C6-C10 arylene;
R 6 and R 7 independently are H, substituted or unsubstituted C1-C5 alkyl;

cycle is azacyclo bonded with (CH 2 ) m SO 3 − via a N atom;
m′ and m″ independently are 1 or 2 ; and
m is an integer within the range of 1-5.

12. The method according to claim 5 , wherein the Zwitter-ionic monomer is in at least one of the structures represented by formulae (ii-1-1), (ii-2-1) and (ii-3-1):

wherein, R 4 , R 4 ′, R 4 ″, R 4 ′″ are same or different, and independently are H, substituted or unsubstituted C1-C5 alkyl.

13. The method according to claim 5 , wherein the cationic polyamine has the structure represented by formula (iii):

wherein, X − is an inorganic anion; R, R 9 , R 9 ′, R 10 and R 10 ′ independently are the structure represented by the following formula (IV):

wherein, R 11 is H, substituted or unsubstituted C1-C5 alkyl, t is an integer within the range of 1-5, and z is an integer within the range of 0-5;
n and p independently are an integer within the range of 1-5; x is an integer within the range of 0-10; y is an integer within the range of 1-10; values of I, I′ and I″ are such that the kinematic viscosity of the cationic polyamine is 100-500 mm 2 /s and the cationic degree of the cationic polyamine is 0.5-2 mmol/g.

14. The method according to claim 13 , wherein

Assignees

• China Petroleum & Chem Corp
• Fushun Res Inst Petroleum & Petrochemicals Sinopec Corp

Inventors

• Yang Chao
• Zhang Zhizhi
• Sun Xiaolei
• Lu Jiao
• Yin Zequn
• Liu Quanjie

Classifications

• C08F220/56

  Acrylamide; Methacrylamide · CPC title

• C09K8/035 Primary

  Organic additives · CPC title

• C09K8/24

  Polymers · CPC title

• C08L33/26

  Homopolymers or copolymers of acrylamide or methacrylamide · CPC title

• C08F222/38 Primary

  Amides · CPC title