ENGINEERED FIBERS FOR WELL TREATMENTS

• US 20100307747A1
• Filed: 05/19/2010
• Published: 12/09/2010
• Est. Priority Date: 06/05/2009
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Kefi, Slaheddine, Ermel, Michel, Cambus-Brunet, Chrystel, Shindgikar, Nikhil, Lee, Jesse
• Granted Patent: US 8,371,381 B2
• Time in Patent Office: Days
• US Class Current: 166/276
• CPC Class Codes: C04B 20/0048 Fibrous materials
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• CPC Class Codes: C09K 2208/08 Fiber-containing well treatment fluids
• CPC Class Codes: C09K 2208/18 Bridging agents, i.e. particles for temporarily filling the pores of a formation; Graded salts
• CPC Class Codes: C09K 8/03 Specific additives for general use in well-drilling compositions
• CPC Class Codes: C09K 8/40 Spacer compositions, e.g. compositions used to separate well-drilling from cementing masses
• CPC Class Codes: C09K 8/426 for plugging
• CPC Class Codes: C09K 8/487 Fluid loss control additives; Additives for reducing or preventing circulation loss
• CPC Class Codes: C09K 8/50 Compositions for plastering borehole walls, i.e. compositions for temporary consolidation of borehole walls compositions for consolidating loose sand or the like around wells C09K8/56
• CPC Class Codes: C09K 8/516 characterised by their form or by the form of their components, e.g. encapsulated material
• CPC Class Codes: C09K 8/80 Compositions for reinforcing fractures, e.g. compositions of proppants used to keep the fractures open
• CPC Class Codes: E21B 21/003 Means for stopping loss of drilling fluid plastering the borehole wall E21B33/138
• CPC Class Codes: E21B 33/13 Methods or devices for cementing, for plugging holes, crevices or the like
• CPC Class Codes: E21B 33/138 Plastering the borehole wall; Injecting into the formation
• CPC Class Codes: E21B 43/267 reinforcing fractures by propping

Abstract

Mixtures of fibers and solid particles are effective for curing fluid losses and lost circulation in a subterranean well. Stiff fibers are more effective than flexible ones; however, mixtures of stiff and flexible fibers have a synergistic effect. The quantity and particle-size distribution of the solids are optimized according to the stiffness, dimensions and concentrations of fibers.

Claims

1. A method for blocking fluid flow through a pathway in a subterranean formation penetrated by a wellbore, comprising the following steps:

(i) selecting compositions, concentrations and dimensions of stiff fibers and solid plugging particles;

(ii) preparing a blocking fluid comprising the stiff fibers and a blend of the solid plugging particles; and

(iii) forcing the blocking fluid into the pathway.

2. The method of claim 1, wherein the stiff fibers form a mesh across the pathway, and the solid particles plug the mesh, thereby blocking fluid flow.

3. The method of claim 1, wherein the stiff fibers have a Young'"'"'s modulus of from about 0.5 to about 100 GPa.

4. The method of claim 1, wherein the stiff fibers have a shortest cross-sectional distance of from about 80 to about 450 microns.

5. The method of claim 1, wherein the length of the stiff fibers is between about 5 to about 24 mm.

6. The method of claim 1, wherein the stiff fibers have a value of the parameter

7. The method of claim 1, wherein the stiff-fiber concentration is from about 2.85 kg/m³ to about 42.8 kg/m³.

8. The method of claim 1, wherein the fluid further comprises fibers that are selected from non-stiff fibers, differing stiff fibers, or both.

9. The method of claim 8, wherein the total fiber concentration is from about 2.85 to about 42.8 kg/m³.

10. The method of claim 8, wherein the non-stiff fibers have a Young'"'"'s modulus of from about 0.5 to about 10 GPa.

11. The method of claim 8, wherein the non-stiff fibers have a shortest cross-sectional distance of from about 10 to about 100 microns.

12. The method of claim 1, wherein the concentration or composition of the stiff fibers is varied.

13. The method of claim 1, wherein the blocking fluid comprises mica.

14. The method of claim 1, wherein the solid volume fraction (SVF) of the solid plugging particles is between 8 and 50 volume percent.

15. The method of claim 1, wherein the solid plugging particles are present as fine, medium and coarse particles, wherein the average particle size of the fine particles is smaller than 30 microns, the average particle size of the medium particles is between 30 microns and 180 microns, and the average particle size of the coarse particles is between 180 micron and 1000 microns.

16. The method of claim 1, wherein the solid plugging particles comprise calcium-carbonate particles.

17. The method of claim 1, wherein the pathway has one dimension across it of at least about 1 mm.

18. The method of claim 1, wherein the pathway is a hydraulic fracture, and fluid flow into the fracture is blocked.

19. A method for treating lost circulation in a well in a subterranean formation penetrated by a wellbore, having one or more pathways in the formation through which fluids escape the wellbore and enter the formation, comprising the following steps:

(i) selecting compositions, concentrations and dimensions of solid plugging particles and fibers, the fibers being stiff fibers, or a mixture of stiff and non-stiff fibers;

(ii) preparing a blocking fluid comprising the fibers and a blend of the solid plugging particles; and

(iii) pumping the blocking fluid into the well continuously until fluid flow into the formation is satisfactorily reduced.

20. A method for treating lost circulation in a well in a subterranean formation penetrated by a wellbore, having one or more pathways in the formation through which fluids escape the wellbore and enter the formation, comprising the following steps:

(i) selecting compositions, concentrations and dimensions of solid plugging particles and fibers, the fibers being stiff fibers, or a mixture of stiff and non-stiff fibers;

(ii) preparing a blocking fluid comprising the fibers and a blend of the solid plugging particles; and

(iii) placing a discrete, desired quantity of blocking fluid adjacent to and/or into a well interval where one or more pathways exist.