Pressure control device for use with a subterranean well

1. A pressure control device for use with a subterranean well, the pressure control device comprising:

a body having a central longitudinal passage, and the body having a laterally extending outlet in communication with the passage;

an annular seal secured to the body and configured to seal off an annulus surrounding a tubular string in the passage;

an inlet longitudinally aligned with, and in communication with, the passage; and

a swivel mechanism having locked and unlocked configurations, the swivel mechanism permitting relative rotation between the body and the inlet about a common longitudinal axis in the unlocked configuration, and the swivel mechanism preventing relative rotation between the body and the inlet in the locked configuration, in which the swivel mechanism comprises a rotary coupling that permits relative rotational displacement between the body and the inlet, but prevents relative longitudinal displacement between the body and the inlet.

2. The pressure control device of claim 1 , in which the swivel mechanism further comprises a lock device including a series of circumferentially distributed teeth and an engagement member, the engagement member engaging the teeth in the locked configuration, and the engagement member being disengaged from the teeth in the unlocked configuration.

3. The pressure control device of claim 2 , in which the teeth are secured relative to the inlet, and the engagement member is rotatable with the body relative to the inlet in the unlocked configuration.

4. The pressure control device of claim 1 , in which the rotary coupling comprises one or more radially displaceable lugs received in recesses in the body and the inlet.

5. The pressure control device of claim 1 , further comprising a collar attached to the annular seal, and radially displaceable lugs that releasably attach the collar to an inner mandrel of a replaceable assembly.

6. The pressure control device of claim 5 , in which the collar is attached to the annular seal with fasteners, the fasteners extending through holes formed through the collar, and in which the fasteners are received in recesses adjacent respective ones of the holes.

7. A method of operating a pressure control device with a subterranean well, the method comprising:

securing an inlet of the pressure control device to an item of well equipment;

then rotating an outlet of the pressure control device about a longitudinal axis of the inlet;

locking a swivel mechanism of the pressure control device, thereby preventing rotation of the outlet relative to the inlet, in which the locking comprises displacing an engagement member into engagement with at least one of multiple circumferentially distributed teeth; and

sealing off an annulus surrounding a tubular string extending through the inlet.

8. The method of claim 7 , in which the rotating comprises rotating the outlet relative to the inlet while the inlet is secured to the item of well equipment.

9. The method of claim 7 , in which the displacing comprises displacing the engagement member radially relative to the inlet.

10. The method of claim 7 , further comprising securing the inlet to a body of the pressure control device by displacing one or more lugs into a position in which the lugs prevent substantial relative longitudinal displacement between the body and the inlet, but permit relative rotation between the body and the inlet.

11. The method of claim 7 , in which the outlet extends laterally from the body, and in which the outlet is in communication with a passage extending longitudinally through the body.

12. The method of claim 7 , further comprising attaching an annular seal as part of a replaceable assembly of the pressure control device, the attaching comprising radially displacing one or more lugs into engagement with an annular recess formed on an inner mandrel of the replaceable assembly.

13. A well system, comprising:

a pressure control device including an annular seal that seals off an annulus surrounding a tubular string extending longitudinally through the pressure control device,

the pressure control device further including an outlet, an inlet secured to an item of well equipment, and a swivel mechanism that permits relative rotation between the outlet and the inlet in an unlocked configuration and prevents relative rotation between the outlet and the inlet in a locked configuration,

the swivel mechanism including circumferentially distributed teeth, and an engagement member that engages at least one of the teeth in the locked configuration, in which the engagement member displaces radially relative to the inlet between engagement and disengagement with the at least one of the teeth.

14. The well system of claim 13 , in which the outlet extends laterally from a body of the pressure control device, and in which the outlet is in communication with a passage extending longitudinally through the body.

15. The well system of claim 13 , in which the engagement member is disengaged from the teeth in the unlocked configuration.

16. The well system of claim 13 , in which the teeth are secured to the inlet, and the engagement member is rotatable with the outlet relative to the inlet in the unlocked configuration.

17. The well system of claim 13 , in which the swivel mechanism comprises a rotary coupling that substantially prevents relative longitudinal displacement between the outlet and the inlet, but permits relative rotational displacement between the outlet and the inlet.

18. The well system of claim 17 , in which the rotary coupling comprises one or more radially displaceable lugs received in a recess in the inlet.