Methods for treating a well bore within an underground formation
View Patent ↗Methods of treating a well bore within an underground formation are disclosed. These methods include: (a) preparing a treatment composition by mixing a polyol-containing component and a polyisocyanate-containing component; and (b) introducing the treatment composition into the well bore. The polyol-containing component includes a polymeric polyol having a viscosity at 25° C. of no more than 1000 mPa·s and the isocyanate-containing component includes an unblocked (cyclo)aliphatic polyisocyanate polymer including allophanate groups and having a viscosity at 25° C. and at least 99% solids of no more than 1000 mPa·s.
1. A method of treating a well bore within an underground formation, comprising:
(a) preparing a treatment composition by mixing a polyol-containing component and a polyisocyanate-containing component; and
(b) introducing the treatment composition into the well bore, wherein
(i) the polyol-containing component comprises a polypropylene-oxide polymeric polyol having a viscosity at 25° C. and at least 99% solids of no more than 1000 mPa·s, and
(ii) the polyisocyanate-containing component comprises an unblocked (cyclo)aliphatic polyisocyanate polymer comprising allophanate groups and having a viscosity at 25° C. and at least 99% solids of no more than 1000 mPa·s,
wherein the polyol-containing component and the polyisocyanate-containing component form a miscible mixture in the treatment composition.
2. The method of claim 1 , wherein (a) comprises surface mixing the polyol-containing component and the polyisocyanate-containing component.
3. The method of claim 1 , wherein the polypropylene-oxide polymeric polyol comprises a polypropylene-oxide triol.
4. The method of claim 3 , wherein the polypropylene-oxide triol has a hydroxyl number of 350 to 390 mg KOH/gram, a water content of less than 0.05% by weight, based on the total weight of the polymeric polyol, and a viscosity at 25° C. and at least 99% solids of 520 to 700 mPa·s.
5. The method of claim 1 , wherein the unblocked (cyclo)aliphatic polyisocyanate polymer is derived from an isocyanate starting material comprising hexamethylene diisocyanate.
6. The method of claim 5 , wherein the isocyanate starting material consists essentially of hexamethylene diisocyanate.
7. The method of claim 6 , wherein the unblocked (cyclo)aliphatic polyisocyanate polymer comprises a trimerized reaction product hexamethylene diisocyanate.
8. The method of claim 1 , wherein the unblocked (cyclo)aliphatic polyisocyanate polymer has an isocyanate content of 10 to 24 weight percent, a viscosity at 25° C. and at least 99% solids of 50 to 900 mPa·s, and a monomeric isocyanate content of less than 1 percent by weight.
9. The method of claim 1 , wherein at least one of the polyol-containing component and the polyisocyanate-containing component comprises a urethane forming catalyst comprising an acid blocked amine and/or an organic metal compound.
10. The method of claim 9 , wherein the catalyst is present in an amount of 0.01 to 2 percent by weight, based on the total weight of the treatment composition.
11. A method of treating a well bore within an underground formation, comprising:
(a) preparing a treatment composition by mixing a polyol-containing component and a polyisocyanate-containing component; and
(b) introducing the treatment composition into the well bore, wherein
(i) the polyol-containing component comprises a polypropylene-oxide triol having a hydroxyl number of 350 to 390 mg KOH/gram, a water content of less than 0.05% by weight, based on the total weight of the polymeric polyol, and a viscosity at 25° C. and at least 99% solids of 520 to 700 mPa·s, and
(ii) the polyisocyanate-containing component comprises an unblocked (cyclo)aliphatic polyisocyanate polymer comprising allophanate groups, wherein the polymer comprises a trimerized reaction product hexamethylene diisocyanate and wherein the polymer has (1) an isocyanate content of 10 to 47% by weight, (2) a viscosity at 25° C. and at least 99% solids of no more than 50 to 900 mPa·s, and (3) a monomeric isocyanate content of less than 0.5 percent by weight,
wherein the polyol-containing component and the polyisocyanate-containing component form a miscible mixture in the treatment composition.
12. The method of claim 11 , wherein (a) comprises surface mixing the polyol-containing component and a polyisocyanate-containing component.
13. The method of claim 11 , wherein the unblocked (cyclo)aliphatic polyisocyanate polymer has an isocyanate content of 10 to 24 weight percent.
14. The method of claim 11 , wherein at least one of the polyol-containing component and the polyisocyanate-containing component comprises a urethane forming catalyst comprising an acid blocked amine and/or an organic metal compound.
15. The method of claim 14 , wherein the catalyst is present in an amount of 0.01 to 2 percent by weight, based on the total weight of the treatment composition.
16. A method of treating a well bore within a porous underground formation, comprising:
(a) preparing a treatment composition by surface mixing a polyol-containing component and a polyisocyanate-containing component;
(b) introducing the treatment composition into the well bore; and
(c) forcing the treatment composition into pores of the porous underground formation under sufficient pressure and for a sufficient time such that the polyol-containing component and the polyisocyanate-containing component react to form a solid polyurethane reaction product that seals pores of the porous underground formation, wherein
(i) the polyol-containing component comprises a polymeric polyol having a viscosity at 25° C. and at least 99% solids of no more than 1000 mPa·s and
(ii) the polyisocyanate-containing component comprises an unblocked (cyclo)aliphatic polyisocyanate polymer comprising allophanate groups and having a viscosity at 25° C. and at least 99% solids of no more than 1000 mPa·s,
wherein the polyol-containing component and the polyisocyanate-containing component form a miscible mixture in the treatment composition.
17. The method of claim 16 , wherein the polymeric polyol comprises a polyalkoxylated triol.
18. The method of claim 17 , wherein the polyalkoxylated triol comprises a polypropylene-oxide triol.
19. The method of claim 18 , wherein the polypropylene-oxide triol has a hydroxyl number of 350 to 390 mg KOH/gram, a water content of less than 0.05% by weight, based on the total weight of the polymeric polyol, and a viscosity at 25° C. and at least 99% solids of 520 to 700 mPa·s.
20. The method of claim 16 , wherein the unblocked (cyclo)aliphatic polyisocyanate polymer is derived from an isocyanate starting material comprising hexamethylene diisocyanate.
21. The method of claim 20 , wherein the isocyanate starting material consists essentially of hexamethylene diisocyanate.
22. The method of claim 21 , wherein the unblocked (cyclo)aliphatic polyisocyanate polymer comprises a trimerized reaction product hexamethylene diisocyanate.
23. The method of claim 22 , wherein the unblocked (cyclo)aliphatic polyisocyanate polymer has an isocyanate content of 10 to 24 weight percent, a viscosity at 25° C. and at least 99% solids of 50 to 900 mPa·s, and a monomeric isocyanate content of less than 1 percent by weight.
24. The method of claim 16 , wherein at least one of the polyol-containing component and the polyisocyanate-containing component comprises a urethane forming catalyst comprising an acid blocked amine and/or an organic metal compound.
25. The method of claim 24 , wherein the catalyst is present in an amount of 0.01 to 2 percent by weight, based on the total weight of the treatment composition.
26. A method of making a lost circulation material within a well bore, the method comprising:
(a) preparing a composition by mixing a polyol-containing component and a polyisocyanate-containing component; and
(b) introducing the composition into the well bore, wherein
(i) the polyol-containing component comprises a polypropylene-oxide triol having a hydroxyl number of 350 to 390 mg KOH/gram, a water content of less than 0.05% by weight, based on the total weight of the polymeric polyol, and a viscosity at 25° C. and at least 99% solids of 520 to 700 mPa·s, and
(ii) the polyisocyanate-containing component comprises an unblocked (cyclo)aliphatic polyisocyanate polymer comprising allophanate groups, wherein the polymer comprises a trimerized reaction product hexamethylene diisocyanate and wherein the polymer has (1) an isocyanate content of 10 to 47% by weight, (2) a viscosity at 25° C. and at least 99% solids of no more than 50 to 900 mPa·s, and (3) a monomeric isocyanate content of less than 0.5 percent by weight,
wherein the polyol-containing component and the polyisocyanate-containing component form a miscible mixture in the treatment composition.