Downhole tool stop device and method for use of same

1. A downhole-tool stop device, the stop device including a first stop collar permanently and non-moveably attached to a section of pipe string, the section of pipe string having a first end portion and a second end portion, the first end portion and second end portion having standard threaded connections to connect the section of pipe string into a pipe string to surface, characterized in that the stop device includes a second stop collar being displaceably attached to the section of pipe string, and the first stop collar and the second stop collar being placed a distance apart.

2. The stop device according to claim 1 , wherein the second stop collar is displaceably attached to the section of pipe string with at least one rupture body.

3. The stop device according to claim 2 , wherein the at least one rupture body is taken from the group consisting of shear screws and shear pins.

4. The stop device according to claim 2 , wherein the at least one rupture body is arranged substantially perpendicularly to the longitudinal direction of the section of pipe string.

5. The stop device according to claim 1 , wherein the second stop collar is attached closer to a second end portion of the section of pipe string than the first stop collar.

6. The stop device according to claim 1 , wherein the section of pipe string comprises a two-part section of pipe string.

7. The stop device according to claim 6 , wherein an upper section and a lower section of the section of pipe string are threadedly connected.

8. The stop device according to claim 7 , wherein the lower section of the section of pipe string is provided with an edge portion arranged to hit the second stop collar.

9. The stop device according to claim 1 , wherein an outer diameter of the first stop collar is larger than an outer diameter of the second stop collar.

10. The stop device according to claim 1 , wherein a downhole tool is attached to a second end portion of the section of pipe string.

11. A method of using a stop device according to claim 1 to release a downhole tool from an underground well, characterized in that the method comprises the steps of:

attaching a downhole tool to the second end portion of the stop device;

running the downhole tool attached to the stop device on a pipe string from surface into an underground well until the second stop collar of the stop device hits a casing;

engaging the downhole tool with the casing by moving the downhole tool and the stop device in a direction out of the underground well;

releasing the engagement of the downhole tool with the casing by moving the downhole tool and the stop device in a direction into the well so that the shear pins of the second stop collar break.