Cavity positioning tool and method

1. A cavity positioning tool, comprising:

a housing adapted to be coupled to a tubing string;

at least one blunt arm coupled to the housing, each blunt arm configured to contact a surface of a cavity to position the tool within the cavity;

a rack coupled to the at least one blunt arm and operable to radially extend the at least one blunt arm in response to an axial force exerted on the rack, the rack comprising an internal fluid passage disposed in fluid communication with an internal passage of the tubing string; and

a rod operable to exert at least a portion of the axial force by pushing from a ground surface.

2. The tool of claim 1 , wherein the rod comprises segmented rods operable to exert the axial force on the rack.

3. The tool of claim 1 , wherein:

each of the at least one blunt arms comprises a pinion; and

the rack is operable to engage each of the respective pinions.

4. The tool of claim 1 , wherein the housing comprises ports allowing fluid to flow into an internal cavity of the housing.

5. A cavity positioning tool, comprising:

a housing adapted to be coupled to a tubing string;

at least one blunt arm coupled to the housing, each blunt arm configured to contact a surface of a cavity to position the tool within the cavity;

a rack coupled to the at least one blunt arm and operable to radially extend the at least one blunt arm in response to an axial force exerted at least in part by a weight operable to selectively exert the axial force on the rack, the rack comprising an internal fluid passage disposed in fluid communication with an internal passage of the tubing string.

6. The tool of claim 5 , wherein the weight is suspended using a wireline.

7. A method for positioning a device relative to a subsurface cavity, comprising:

coupling a housing to a string, wherein the housing comprises an internal fluid passage disposed in fluid communication with the string;

coupling one or more blunt arms to the housing, wherein the one or more blunt arms is configured to contact a surface of the subsurface cavity to position the tool within the cavity;

disposing the housing within the subsurface cavity;

applying an axial force to a body coupled to the blunt arms; and

extending the one or more blunt arms radially outward relative to the housing in response to the axial force;

wherein applying the axial force comprises applying a weight to the body.

8. The method of claim 7 , wherein:

the body comprises a rack engaging a pinion on each of the blunt arms; and

extending the one or more blunt arms comprises moving the rack downward.

9. The method of claim 7 , wherein applying the weight comprises lowering the weight onto the body.

10. The method of claim 7 , wherein applying the weight comprises resting the weight on the body.

11. The method of claim 10 , wherein the weight is a sinker bar depending from a wireline.

12. The method of claim 7 , further comprising pumping fluid from the cavity through the internal fluid passage.

13. The method of claim 12 , wherein:

the body is disposed within the internal fluid passage; and

the method further comprises removing the body from the internal fluid passage.

14. A method for positioning a device relative to a subsurface cavity, comprising:

coupling a housing to a string, wherein the housing comprises an internal fluid passage disposed in fluid communication with the string;

coupling one or more blunt arms to the housing, wherein the one or more blunt arms is configured to contact a surface of the subsurface cavity to position the tool within the cavity;

disposing the housing within the subsurface cavity;

applying an axial force to a body coupled to the blunt arms; and

extending the one or more blunt arms radially outward relative to the housing in response to the axial force;

wherein:

the string extends from a ground surface; and

applying the axial force comprises pushing the body from the ground surface.