Cross-linked polyrotaxanes and their application in cement
This document relates to methods for preventing or inhibiting the formation of micro-cracks and fractures in the cement of an oil well using cement compositions that contain cross-linked polyrotaxane additives. The cement compositions containing the cross-linked polyrotaxane additives exhibit increased stiffness without suffering a decrease in compressive strength, as compared to the same cement without the cross-linked polyrotaxane additive.
1. A cement composition comprising:
cement; and
a cross-linked polyrotaxane additive comprising:
a polyrotaxane comprising a linear polymer and at least one ring compound, wherein the linear polymer is threaded through the opening of the ring compound; and
a cross-linker.
2. The composition of claim 1 , wherein the linear polymer is selected from the group consisting of a polyethylene glycol (PEG), a propylene glycol (PPG), a block copolymer of PEG and PPG, and a polysiloxane (PS).
3. The composition of claim 2 , wherein the linear polymer terminates with one or more of —NH 2 , —COOH, —OH, —CH 2 ═CH 2 , —COCH 2 (CH 3 )═CH 2 , —SH, —COCl, or a halide.
4. The composition of claim 3 , wherein the linear polymer is a PEG or a polysiloxane that terminates with one or more NH 2 groups.
5. The composition of claim 3 , wherein the linear polymer is a PEG or a polysiloxane that terminates with one or more —COOH groups.
6. The composition of claim 1 , wherein the linear polymer has a molecular weight of about 2000 g/mol to about 50000 g/mol, about 8000 g/mol to about 30,000 g/mol, or about 15,000 g/mol to about 25,000 g/mol.
7. The composition of claim 1 , wherein the linear polymer has a molecular weight of about 20,000 g/mol, about 25,000 g/mol, or about 28,000 g/mol.
8. The composition of claim 1 , wherein the ring compound is a cyclodextrin or cyclodextrin derivative.
9. The composition of claim 8 , wherein the cyclodextrin is selected from the group consisting of α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), and γ-cyclodextrin (γ-CD) and combinations thereof.
10. The composition of claim 1 , wherein the amount of ring compound in the polyrotaxane is between about 20% to about 70%, about 50% to about 60%, or about 30% to about 40% by weight of the polyrotaxane.
11. The composition of claim 1 , wherein the polyrotaxane is selected from the group consisting of γ-CD-PS-NH 2 , γ-CD-PS-COOH, β-CD-PPG-NH 2 , and α-CD-PEG-NH 2 .
12. The composition of claim 1 , wherein the polyrotaxane comprises a stopper group at one or both ends of the linear polymer.
13. The composition of claim 12 , wherein the stopper group is selected from the group consisting of a dinitrofluorophenyl group, a cyclodextrin, a nitrophenol, and combinations thereof.
14. The composition of claim 13 , wherein the stopper group is p-nitrophenol (PNP) or 2,4-dinitrofluorobenzene (DNF).
15. The composition of claim 13 , wherein the polyrotaxane is α-CD-PEG-NH-DNF or γ-CD-PS-COOH-PNP.
16. The composition of claim 1 , wherein the cross-linker is selected from the group consisting of trimesoyl chloride, formaldehyde, cyanuric chloride (CC), and bisphenol A diglycidyl ether (DGE).
17. The composition of claim 1 , wherein the amount of cross-linker in the cross-linked polyrotaxane additive is between about 1% to about 10%, or about 2% to about 7%, or about 2% to about 4% by weight of the cross-linked polyrotaxane additive.
18. The composition of claim 17 , wherein the amount of cross-linker in the cross-linked polyrotaxane additive is about 3% by weight of the cross-linked polyrotaxane additive.
19. The composition of claim 1 , wherein the cross-linked polyrotaxane additive is selected from the group consisting of γ-CD-PS-NH-CC, γ-CD-PS-NH-DGE, γ-CD-PS-COO-DGE, α-CD-PEG-NH-P, and γ-CD-PS-COOH-P, wherein P is a polymer obtained from self-polymerization of the polyrotaxane.
20. The composition of claim 19 , wherein the cross-linked polyrotaxane additive is γ-CD-PS-COOH-P.
21. The composition of claim 1 , wherein the amount of cross-linked polyrotaxane additive in the cement composition is between about 0.1% to about 6%, about 1% to about 4%, or about 2% to about 3% by weight of the cement composition.
22. The composition of claim 21 , wherein the amount of cross-linked polyrotaxane additive in the cement composition is about 0.8% to about 1% by weight of the cement composition.
23. The composition of claim 1 , wherein the cement composition comprises one or more of a suspending agent or an anti-foaming agent.
24. The composition of claim 23 , wherein the one or more suspending agent or anti-foaming agent is hydroxyethylcellulose or a mixture of glycols, silicon-based compounds, and compounds with carboxylate functional groups.
25. The composition of claim 1 , wherein the cement composition further comprises water.
26. The composition of claim 25 , wherein the ratio of cement to water in the cement composition is about 50:50, about 60:40, or about 70:30 wt/v.
27. The composition of claim 1 , wherein the cement composition has a Young's modulus of about 0.1 GPa to about 40 GPa, about 3 GPa to about 25 GPa, or about 5 GPa to about 20 GPa at a pressure of about 0.1 MPa to about 150 MPa, about 10 MPa to about 100 MPa, or about 20 MPa to about 40 MPa, at a temperature of about 77° F. to about 450° F., about 125° F. to about 350° F., or about 150° F. to about 200° F.
28. The composition of claim 27 , wherein the cement composition has a Young's modulus of about 5 GPa to about 10 GPa at a pressure of about 20 MPa and a temperature of about 180° F.
29. The composition of claim 1 , wherein the cement composition has a compressive strength of about 1000 psi to about 10,000 psi, about 2000 psi to about 8000 psi, or about 3500 psi to about 6500 psi, at a pressure of about 0.1 MPa to about 150 MPa, about 10 MPa to about 100 MPa, or about 20 MPa to about 40 MPa, at a temperature of about 77° F. to about 450° F., about 125° F. to about 350° F., or about 150° F. to about 200° F.
30. The composition of claim 29 , wherein the cement composition has a compressive strength of about 4500 psi to about 5500 psi at a pressure of about 20 MPa and a temperature of about 180° F.
31. The composition of claim 1 , wherein the cement composition exhibits improved stiffness as compared to the same composition without the cross-linked polyrotaxane additive.
32. A method of preparing a cement composition, comprising:
a) reacting a polyrotaxane comprising a linear polymer and at least one ring compound, wherein the linear polymer is threaded through the opening of the ring compound, with a cross-linker to form a cross-linked polyrotaxane additive; and
b) mixing the cross-linked polyrotaxane additive with cement.
33. The method of claim 32 , wherein the linear polymer is selected from the group consisting of a polyethylene glycol (PEG), a propylene glycol (PPG), a block copolymer of PEG and PPG, and a polysiloxane (PS).
34. The method of claim 33 , wherein the linear polymer terminates with one or more of —NH 2 , —COOH, —OH, —CH 2 ═CH 2 , —COCH 2 (CH 3 )═CH 2 , —SH, —COCl, or a halide.
35. The method of claim 32 , wherein the linear polymer has a molecular weight of about 2000 g/mol to about 50000 g/mol, about 8000 g/mol to about 30,000 g/mol, or about 15,000 g/mol to about 25,000 g/mol.
36. The method of claim 32 , wherein the ring compound is a cyclodextrin or cyclodextrin derivative.
37. The method of claim 36 , wherein the cyclodextrin is selected from the group consisting of α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), and γ-cyclodextrin (γ-CD) and combinations thereof.
38. The method of claim 32 , wherein the amount of ring compound in the polyrotaxane is between about 20% to about 70%, about 50% to about 60%, or about 30% to about 40% by weight of the polyrotaxane.
39. The method of claim 32 , wherein the polyrotaxane is selected from the group consisting of γ-CD-PS-NH 2 , γ-CD-PS-COOH, β-CD-PPG-NH 2 , and α-CD-PEG-NH 2 .
40. The method of claim 32 , wherein the polyrotaxane comprises a stopper group at one or both ends of the linear polymer.
41. The method of claim 40 , wherein the stopper group is selected from the group consisting of a dinitrofluorophenyl group, a cyclodextrin, a nitrophenol, and combinations thereof.
42. The method of claim 41 , wherein the stopper group is p-nitrophenol (PNP) or 2,4-dinitrofluorobenzene (DNF).
43. The method of claim 41 , wherein the polyrotaxane is α-CD-PEG-NH-DNF or γ-CD-PS-COOH-PNP.
44. The method of claim 32 , wherein the cross-linker is selected from the group consisting of trimesoyl chloride, formaldehyde, cyanuric chloride (CC), and bisphenol A diglycidyl ether (DGE).
45. The method of claim 32 , wherein the amount of cross-linker in the cross-linked polyrotaxane additive is between about 1% to about 10%, or about 2% to about 7%, or about 2% to about 4% by weight of the cross-linked polyrotaxane additive.
46. The method of claim 32 , wherein the cross-linked polyrotaxane additive is selected from the group consisting of γ-CD-PS-NH-CC, γ-CD-PS-NH-DGE, γ-CD-PS-COO-DGE, α-CD-PEG-NH-P, and γ-CD-PS-COOH-P, wherein P is a polymer obtained from self-polymerization of the polyrotaxane.
47. The method of claim 46 , wherein the cross-linked polyrotaxane additive is γ-CD-PS-COOH-P.
48. The method of claim 32 , wherein the amount of cross-linked polyrotaxane additive in the cement composition is between about 0.1% to about 6%, about 1% to about 4%, or about 2% to about 3% by weight of the cement composition.
49. The method of claim 32 , wherein the cement composition comprises one or more of a suspending agent or an anti-foaming agent.
50. The method of claim 32 , wherein the cement composition further comprises water.
51. The method of claim 50 , wherein the ratio of cement to water in the cement composition is about 50:50, about 60:40, or about 70:30 wt/v.
52. A method for preventing the formation of micro-cracks and fractures in the cement of an oil well, the method comprising providing to the oil well a cement composition comprising cement and a cross-linked polyrotaxane additive, the cross-linked polyrotaxane additive comprising:
a polyrotaxane comprising a linear polymer having a molecular weight of about 2000 g/mol to about 50000 g/mol, and at least one ring compound, wherein the linear polymer is threaded through the opening of the ring compound; and
a cross-linker.
53. The method of claim 52 , wherein the linear polymer is selected from the group consisting of a polyethylene glycol (PEG), a propylene glycol (PPG), a block copolymer of PEG and PPG, and a polysiloxane (PS).
54. The method of claim 53 , wherein the linear polymer terminates with one or more of —NH 2 , —COOH, —OH, —CH 2 ═CH 2 , —COCH 2 (CH 3 )═CH 2 , —SH, —COCl, or a halide.
55. The method of claim 52 , wherein the ring compound is a cyclodextrin selected from the group consisting of α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), and γ-cyclodextrin (γ-CD) and combinations thereof.
56. The method of claim 52 , wherein the polyrotaxane is selected from the group consisting of γ-CD-PS-NH 2 , γ-CD-PS-COOH, β-CD-PPG-NH 2 , and α-CD-PEG-NH 2 .
57. The method of claim 52 , wherein the polyrotaxane comprises a stopper group at one or both ends of the linear polymer.
58. The method of claim 57 , wherein the stopper group is selected from the group consisting of a dinitrofluorophenyl group, a cyclodextrin, a nitrophenol, and combinations thereof.
59. The method of claim 58 , wherein the polyrotaxane is α-CD-PEG-NH-DNF or γ-CD-PS-COOH-PNP.
60. The method of claim 52 , wherein the cross-linker is selected from the group consisting of trimesoyl chloride, formaldehyde, cyanuric chloride (CC), and bisphenol A diglycidyl ether (DGE).
61. The method of claim 52 , wherein the amount of cross-linker in the cross-linked polyrotaxane additive is between about 1% to about 10%, or about 2% to about 7%, or about 2% to about 4% by weight of the cross-linked polyrotaxane additive.
62. The method of claim 52 , wherein the cross-linked polyrotaxane additive is selected from the group consisting of γ-CD-PS-NH-CC, γ-CD-PS-NH-DGE, γ-CD-PS-COO-DGE, α-CD-PEG-NH-P, and γ-CD-PS-COOH-P, wherein P is a polymer obtained from self-polymerization of the polyrotaxane.
63. The method of claim 52 , wherein the amount of cross-linked polyrotaxane additive in the cement composition is between about 0.1% to about 6%, about 1% to about 4%, or about 2% to about 3% by weight of the cement composition.
64. The method of claim 52 , wherein the cement composition comprises one or more of a suspending agent or an anti-foaming agent.
65. The method of claim 52 , wherein the cement composition further comprises water.
66. The method of claim 65 , wherein the ratio of cement to water in the cement composition is about 50:50, about 60:40, or about 70:30 wt/v.