Degradable material assisted diversion or isolation
A method for well treatment by forming a temporary plug in a fracture, a perforation, a wellbore, or more than one of these locations, in a well penetrating a subterranean formation is provided, in which the method of well treatment includes: injecting a slurry comprising a degradable material, allowing the degradable material to form a plug in a perforation, a fracture, or a wellbore in a well penetrating a formation; performing a downhole operation; and allowing the degradable material to degrade after a selected time such that the plug disappears.
1. A method of well treatment, comprising:
a) injecting a slurry comprising a degradable fiber,
b) allowing the degradable fiber to form a plug in one or more than one of a perforation, a fracture, and a wellbore in a well penetrating a formation;
c) performing a downhole operation; and
d) allowing the degradable fiber to at least partially degrade after a selected duration such that the plug disappears.
2. The method of claim 1 , wherein the degradable fiber is selected from a polymer of lactide, glycolide, polylactic acid, polyglycolic acid, amide, and mixtures thereof.
3. The method of claim 1 , wherein the degradable fiber is present at a concentration of no less than 40 lbm/1,000 gal (4.8 g/L).
4. The method of claim 1 , wherein the operation is a fracturing operation and the method further comprises injecting a second material to induce a screenout during the fracturing operation.
5. The method of claim 1 , wherein the slurry further comprises a particulate material.
6. The method of claim 5 , wherein the particulate material is degradable.
7. The method of claim 5 , wherein the particulate material is a proppant.
8. The method of claim 7 , wherein the proppant comprises particles having a distribution of sizes.
9. The method of claim 1 , wherein the slurry further comprises an additive for delaying degradation of the degradable fiber.
10. The method of claim 1 , wherein the slurry further comprises an additive for accelerating degradation of the degradable fiber.
11. The method of claim 1 , further comprising modeling to optimize parameters for the well treatment, wherein the step of injecting the slurry is based on the optimized parameters.
12. The method of claim 11 , wherein the optimized parameters comprise the selected duration before the degradable fiber degrades.
13. The method of claim 1 , wherein the well treatment comprises hydraulic fracturing.
14. The method of claim 13 , wherein the hydraulic fracturing comprises injecting a pad, said pad comprising the degradable fiber.
15. The method of claim 14 , wherein the step of injecting the slurry is performed at the tail end of fracturing a layer.
16. The method of claim 13 , wherein hydraulic fracturing is applied to more than one layer of a multilayer formation.
17. The method of claim 16 , wherein no bridge plug or sand plug is placed in the wellbore before fracturing a subsequent layer.
18. The method of claim 16 , wherein the slurry further comprises a proppant, wherein the degradable fiber forms the plug in the fracture by bridging with the proppant when placed in the fracture.
19. The method of claim 1 , wherein the well treatment comprises acid fracturing or waterfrac.
20. The method of claim 1 , wherein the selected duration for the plug to disappear is between 0.5 and 6 hours.
21. The method of claim 1 , wherein the step of injecting the slurry is via coiled tubing installed in the well.
22. The method of claim 1 wherein the degradable fiber comprises a polyvinyl ester.
23. The method of claim 1 , wherein the treatment is used to isolate a region selected from the fracture, a production zone, and a part of the wellbore, wherein the part of the wellbore is above the formation pressure.
24. The method of claim 1 , wherein the degradable fiber is selected from limestone fibers and glass fibers.
25. The method of claim 1 , wherein the well treatment comprises chemical strimulation.