Wood-based loss circulation material and method for manufacturing same

• US 9,290,687 B1
• Filed: 06/12/2012
• Issued: 03/22/2016
• Est. Priority Date: 06/12/2012
• Status: Active Grant

• Current Assignee: Fiber Resources, Inc.
• Original Assignee: Fiber Resources, Inc.
• Inventors: Weaver, William R.
• Primary Examiner(s): Li, Aiqun
• Application Number:
  US13/494,743
• Time in Patent Office: 1,379 Days
• Field of Search: 507/104, 507/204
• US Class Current: 1/1
• CPC Class Codes: C09K 2208/08 Fiber-containing well treatment fluids
• CPC Class Codes: C09K 8/035 Organic additives
• CPC Class Codes: C09K 8/516 characterised by their form or by the form of their components, e.g. encapsulated material

Abstract

A wood-based loss circulation material is formed with a density matched to the density of the drilling fluid to which the loss circulation material will be added. The material is formed from sawdust or fiber pressed under high pressure into high-density pellets. The resulting pellets are brittle, and may be crumbled and screened into particles of an appropriate size for a particular drilling fluid application. Different particle sizes may be employed to prevent seepage or fill voids during the well drilling process. The particles do not disassociate into their constituent materials when in the drilling fluid, and thus maintain their density during use.

Claims

1. A loss circulation material for introduction into a drilling fluid, the material comprising a mixture of crumbled pellet particles of a plurality of grades, the crumbled pellet particles consisting essentially of wood fiber and moisture without an additional binder material, wherein each of said crumbled pellet particles comprises a particle diameter, further wherein said plurality of grades comprises a coarse particle grade, a medium particle grade, and a fine particle grade, wherein said particle diameter of said crumbled pellet particles of said coarse particle grade is greater than 0.0394 inches, further wherein said particle diameter of said crumbled pellet particles of said medium particle grade is between 0.0098 inches and 0.0394 inches, further wherein said particle diameter of said crumbled pellet particles of said fine particle grade is between 0.0029 inches and 0.0098 inches, wherein the crumbled pellet particles have a specific gravity greater than 1.0, and further wherein the crumbled pellet particles remain substantially integral when introduced into the drilling fluid.

2. The loss circulation material of claim 1, wherein said wood fiber consists essentially of hardwood wood fiber.

3. The loss circulation material of claim 2, wherein said wood fiber consists essentially of oak wood fiber.

4. The loss circulation material of claim 1, wherein the specific gravity of the crumbled pellet particles is in the range of 1.1 to 1.3.

5. The loss circulation material of claim 1, wherein the specific gravity of the mixture of crumbled pellet particles is within 10% of the specific gravity of the drilling fluid.

6. The loss circulation material of claim 1, wherein the moisture comprises 4 to 8% of the crumbled pellet particles by weight.

7. A method for augmenting a drilling fluid with a loss circulation material, the material comprising a plurality of crumbled pellets, the crumbled pellets consisting essentially of wood and moisture, said method comprising the steps of:

(a) acquiring a hardwood material;

(b) drying the hardwood material;

(c) grinding the hardwood material to produce a uniform hardwood material;

(d) pelletizing the uniform hardwood material to produce pellets;

(e) cooling the pellets;

(f) crumbling the pellets to produce particles wherein said particles comprise a particle diameter, the particles having a specific gravity greater than 1.0;

(g) grading the particles by means of a plurality of screens,

wherein said plurality of screens comprise a 18 mesh size screen, a 60 mesh size screen, and a 200 mesh size screen, further wherein said graded particles comprise a coarse particle grade, a medium particle grade, and a fine particle grade, wherein said particle diameter of said particles of said coarse particle grade is greater than 0.0394 inches, further wherein said particle diameter of said particles of said medium particle grade is between 0.0098 inches and 0.0394 inches, further wherein said particle diameter of said particles of said fine particle grade is between 0.0029 inches and 0.0098 inches, further wherein said particles of said coarse particle grade are captured by said 18 mesh size screen, further wherein said particles of said medium particle grade pass through said 18 mesh size screen and are captured by said 60 mesh size screen, further wherein said particles of said fine particle grade pass through said 18 mesh size screen and said 60 mesh size screen and are captured by said 200 mesh size screen; and

(h) mixing the graded particles with the drilling fluid, wherein the particles remain substantially integral within the drilling fluid after the mixing step.

8. The method of claim 7, wherein the mixing step comprises the step of adding the graded particles to the drilling fluid in a mud pit.

9. A method for manufacturing a loss circulation material for introduction into a drilling fluid, wherein the loss circulation material consists essentially of wood and water, said method comprising the steps of:

(a) drying a wood source material to a desired moisture content;

(b) pelletizing the source material to produce a plurality of pellets, wherein the specific gravity of the plurality of pellets is greater than 1.0;

(c) crumbling the pellets into smaller crumbled pellet particles, wherein said crumbled pellet particles comprise a particle diameter;

(d) screening the crumbled pellet particles through a plurality of mesh screens to produce a plurality of crumbled pellet particle size grades, wherein said plurality of mesh screens comprise a 18 mesh size screen, a 60 mesh size screen, and a 200 mesh size screen, further wherein said crumbled pellet particle size grades comprise a coarse particle grade, a medium particle grade, and a fine particle grade, wherein said particle diameter of said crumbled pellet particles of said coarse particle grade is greater than 0.0394 inches, further wherein said particle diameter of said crumbled pellet particles of said medium particle grade is between 0.0098 inches and 0.0394 inches, further wherein said particle diameter of said crumbled pellet particles of said fine particle grade is between 0.0029 inches and 0.0098 inches, further wherein said crumbled pellet particles of said coarse particle grade are captured by said 18 mesh size screen, further wherein said crumbled pellet particles of said medium particle grade pass through said 18 mesh size screen and are captured by said 60 mesh size screen, further wherein said crumbled pellet particles of said fine particle grade pass through said 18 mesh size screen and said 60 mesh size screen and are captured by said 200 mesh size screen; and

(e) mixing at least two of the crumbled pellet particle size grades to produce a mixture of crumbled pellet particle grades in the loss circulation material.

10. The method of claim 9, wherein said drying step comprises the step of drying the source material to 10% to 14% moisture content by weight.

11. The method of claim 10, further comprising the step of grinding the source material to a uniform size prior to the pelletizing step.

12. The method of claim 11, wherein the pellets produced in the pelletizing step comprise a bulk density in the range of 22 pounds per cubic foot to 34 pounds per cubic foot.

13. The method of claim 9, wherein the screening step further comprises the step of returning any oversized crumbled pellet particles to the crumbling step.

14. The method of claim 9, wherein the mixture of crumbled pellet particles specific gravity is within 10% of the specific gravity of the particular drilling mud.