Hydrocarbon well treatment methods and fluids
View Patent ↗A treatment method for a hydrocarbon well includes placing a well treatment fluid containing a viscosifying agent in the well and, using the viscosifying agent, attaining a first viscosity of the fluid in the well. The method includes combining a porphyrin compound with the fluid and, using the porphyrin compound, decreasing viscosity of the fluid in the well to a second viscosity less than the first viscosity. A hydrocarbon well treatment fluid includes an aqueous carrier fluid, a polymer viscosifying agent, and a chlorophyll compound.
1. A treatment method for a hydrocarbon well comprising:
placing a well treatment fluid containing a viscosifying agent in the well;
using the viscosifying agent, attaining a first viscosity of the fluid in the well;
combining a porphyrin compound with the fluid, the porphyrin compound including four modified pyrrole subunits forming a ring; and
using the porphyrin compound, decreasing viscosity of the fluid in the well to a second viscosity less than the first viscosity.
2. The method of claim 1 wherein the viscosifying agent comprises a polymer.
3. The method of claim 1 wherein the fluid placed in the well further comprises a cross-linker of the viscosifying agent and attaining the first viscosity comprises cross-linking the viscosifying agent.
4. The method of claim 3 wherein the cross-linker comprises borate.
5. The method of claim 1 wherein the porphyrin compound is a chlorophyll compound.
6. The method of claim 5 wherein the chlorophyll compound is in the form of a liquid extract from plant material with the plant material strained therefrom and the use of the chlorophyll compound comprises attaining a concentration of chlorophyll in the well treatment fluid of about 200 mg/L or greater.
7. The method of claim 1 further comprising hydraulically fracturing the well after attaining the first viscosity and before decreasing viscosity of the fluid in the well.
8. The method of claim 1 wherein decreasing viscosity of the fluid in the well comprises breaking the fluid to the second viscosity, which is less than about 10 cP at 100 sec −1 .
9. The method of claim 1 wherein decreasing viscosity of the fluid occurs at a temperature of about 75° F. or greater and at a pressure greater than 15 psi.
10. The method of claim 1 wherein decreasing viscosity of the fluid occurs at a pH of about 8.5 or greater.
11. The method of claim 1 wherein, after the decrease in viscosity of the fluid in the well to the second viscosity, the method further comprises removing the fluid from the well, the fluid's viscosity remaining substantially at the second viscosity or less throughout the removal.
12. The method of claim 11 further comprising decreasing the temperature of the fluid to less than 175° F. during at least part of the removal.
13. A treatment method for a hydrocarbon well comprising:
placing a well treatment fluid containing a polymer viscosifying agent in the well;
using the viscosifying agent, attaining a first viscosity of the fluid in the well;
hydraulically fracturing the well after attaining the first viscosity;
combining chlorophyll with the fluid;
using the chlorophyll, decreasing viscosity of the fluid in the well after the hydraulic fracturing to a second viscosity less than the first viscosity at a temperature of about 150° F. or greater, at a pressure greater than 15 psi, and at a pH of about 9.5 or greater; and
after the decrease in viscosity, removing the fluid from the well, the viscosity remaining substantially at the second viscosity or less throughout the removal and the temperature of the fluid decreasing to less than 175° F. during at least part of the removal.
14. The method of claim 13 wherein the fluid placed in the well further comprises a borate cross-linker of the viscosifying agent and attaining the first viscosity comprises cross-linking the viscosifying agent.
15. The method of claim 13 wherein the chlorophyll is in the form of a liquid extract from plant material with the plant material strained therefrom and using the chlorophyll comprises attaining a concentration of chlorophyll in the well treatment fluid of about 200 mg/L or greater.
16. The method of claim 13 wherein decreasing viscosity of the fluid in the well comprises breaking the fluid to the second viscosity, which is less than about 10 cP at 100 sec −1 .
17. The method of claim 13 wherein, for the decrease in viscosity, the temperature of about 150° F. or greater is about 150 to about 250° F., the pressure greater than 15 psi is greater than 100 psi, and the pH of about 9.5 or greater is about 9.5 to about 11.
18. The method of claim 5 wherein the chlorophyll compound is chlorophyll A.
19. The method of claim 13 wherein the chlorophyll is chlorophyll A.
20. A treatment method for a hydrocarbon well comprising:
placing a well treatment fluid containing a polymer viscosifying agent in the well;
using the viscosifying agent, attaining a first viscosity of the fluid in the well;
hydraulically fracturing the well after attaining the first viscosity;
combining chlorophyll with the fluid;
using the chlorophyll, decreasing viscosity of the fluid in the well after the hydraulic fracturing to a second viscosity less than the first viscosity at a temperature of about 150° F. or greater, at a pressure greater than 15 psi, and at a pH of about 9.5 or greater.