Apparatus and methods for well intervention

1. An apparatus comprising:

a downhole tool string for conveying within a wellbore, wherein the downhole tool string comprises: an engagement device having one or more engagement members operable to engage a downhole feature located within the wellbore; a first actuator operable to apply a substantially non-vibrating force to the engagement device while the engagement device is engaged with the downhole feature; and a second actuator operable to apply a vibrating force to the engagement device while the engagement device is engaged with the downhole feature, wherein the vibrating force is capable of moving the downhole feature either alone or in combination with the non-vibrating force, wherein the second actuator is located between the first actuator and the engagement device.

2. The apparatus of claim 1 wherein a valve installed in the wellbore comprises the downhole feature.

3. The apparatus of claim 2 wherein the substantially non-vibrating force and the vibrating force are cooperative for transitioning the valve between open and closed positions.

4. The apparatus of claim 2 wherein the valve comprises a sliding sleeve comprising the downhole feature.

5. The apparatus of claim 1 wherein the first actuator applies the substantially non-vibrating force to the second actuator, such that the second actuator applies a combination of the substantially non-vibrating and vibrating forces to the engagement device.

6. The apparatus of claim 1 wherein the first and second actuators are simultaneously operable to apply the substantially non-vibrating and vibrating forces to the downhole feature, via the engagement device, to move the downhole feature within the wellbore.

7. The apparatus of claim 1 wherein the substantially non-vibrating force is an axial force, and wherein the vibrating force is an axially vibrating force.

8. The apparatus of claim 1 wherein the substantially non-vibrating force is an axial force, and wherein the vibrating force is a radially vibrating force.

9. The apparatus of claim 1 wherein the substantially non-vibrating force is an axial force, and wherein the vibrating force is a rotationally vibrating force.

10. The apparatus of claim 1 wherein:

the second actuator comprises:

a rotor comprising alternating slots and protrusions;

a rotary actuator operable to rotate the rotor; and

a contact member operable to contact the rotor; and

the alternating slots and protrusions of the rotor are operable to move the contact member in an oscillating manner as the rotor rotates to generate the vibrating force.

11. The apparatus of claim 1 wherein the one or more engagement members are extendable and operable for on-time engagement to the downhole feature.

12. The apparatus of claim 11 wherein the one or more engagement members are broken to disengage from the downhole feature.

13. The apparatus of claim 1 wherein the one or more engagement members are extendable and retractable.

14. The apparatus of claim 1 wherein the engagement device is a setting tool or a shifting tool.

15. An apparatus comprising:

a downhole tool string for conveying within a wellbore, wherein the downhole tool string comprises:

an engagement device having one or more engagement members operable to engage a downhole feature located within the wellbore;

a first actuator operable to apply a substantially non-vibrating force to the engagement device while the engagement device is engaged with the downhole feature; and

a second actuator operable to apply a vibrating force to the engagement device while the engagement device is engaged with the downhole feature;

wherein the one or more engagement members are extendable and operable for on-time engagement to the downhole feature;

wherein the one or more engagement members are broken to disengage from the downhole feature.