Thermal Well Completion (Patent No: 894602)

Inventor: Tod, James F.

Location: Edmonton

Comments: N/A

Description: The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Apparatus for attaching a subsurface cementing device to the outer periphery of a free moving section of a pipe string to be run in a thermal well, said cementing device having at least one collar slidably mountable around said pipe, said apparatus comprising: a sleeve adapted to fit circumferentially around said pipe and composed of heat sensitive material rigid at normal subsurface temperatures and deformable at a predetermined heat treating temperature; and means for securing said sleeve to said pipe in engaging relation to said collar whereby said device and pipe are maintained in fixed relation at normal subsurface temperatures and are relatively movable at temperatures equal to and greater than said predetermined heat treating temperature.

2. The invention as recited in claim 1 wherein said sleeve is composed of a low-melting alloy.

3. The invention as recited in claim 2 wherein said alloy is a bismuth alloy fusible at temperatures from about 100°F to about 300°F.

4. The invention as recited in claim 2 wherein said bismuth alloy contains 7 to 8 parts bismuth, 4 parts lead, 2 parts tin, and 1 to 2 parts cadmium.

5. The invention as recited in claim 1 wherein said heat sensitive material is a thermoplastic resin.

6. The invention as recited in claim 1 wherein said sleeve is disposed intermediate said collar and said pipe, and said means for securing said sleeve includes clamping means mounted on said collar for applying a compressive force to said sleeve.

7. The invention as recited in claim 1 wherein said sleeve is mounted on said pipe in end-to-end abutting relation to said collar, and said means for securing said sleeve includes clamping means mounted on said sleeve for grippingly securing said sleeve about said pipe.

8. A centralizer for attachment to the outer periphery of pipe to be run in a thermal well, said centralizer comprising: a pair of spaced collars particularly sized to fit about the periphery of said pipe at a longitudinally spaced interval, one of said collars being composed of heat sensitive material rigid at normal subsurface temperatures and deformable at a predetermined heat treating temperature; means for securing said one collar to said pipe: and outwardly bowed spring members interconnecting said collars.

9. The invention as recited in claim 8 wherein said one collar is composed of a bismuth alloy having a melting temperature in the range from about 100°F to about 300°F.

10. Apparatus for positioning devices on the outer periphery of pipe to be used in thermal wells, said apparatus comprising: a collar sized to fit about the periphery of said pipe and adapted to engage a portion of said device maintaining it in fixed relation to said pipe, said collar being composed of heat sensitive material rigid at normal subsurface temperatures and deformable at a predetermined elevated treating temperature; and means -for securing said collar to said pipe.

11. A subsurface cementing device for use in installing pipe in a thermal well, said device comprising: a body; a plurality of spring members extending radially outwardly from said body; and a sleeve extending circumferentially around said pipe and connecting said body to said pipe for maintaining fixed relative positions thereof, said sleeve being composed of heat sensitive material rigid at normal subsurface temperatures and being deformable at a predetermined elevated heat treating temperature whereby said body and pipe are maintained in fixed relation at normal subsurface temperatures and are relatively movable at temperatures equal to and greater than said predetermined elevated heat treating temperature.

12. A method for attaching a collared device to a free moving section of pipe to be used in thermal wells, said method comprising the steps of: positioning said device on said pipe wherein said device collar is disposed circumferentially around said pipe; pouring a molten fusible material in the annulus separating said collar and said pipe, said material having a melting temperature above normal subsurface temperatures but substantia11y below the maximum heat treating temperature; and permitting said alloy to solidify whereby said device is firmly bonded to said pipe.

13. The invention as recited in claim 12 wherein said alloy is a bismuth alloy having a melting temperature below 200°F.

14. The invention as recited in claim 13 wherein said alloy is composed of 7 to 8 parts bismuth, 4 parts lead, 2 parts tin, and 1 to 2 parts cadmium.