Cross-linked polyrotaxanes and their application in cement
AssigneeSaudi Arabian Oil Company
InventorsHasmukh A. Patel, Peter Boul, Carl Thaemlitz
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Abstract
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.
Claims66
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.
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.
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.
Dependencies are inferred from the claim text.