Choke mechanism for a lubricator

Abstract

A lubricator and plunger catcher used in conjunction with an oil or gas well includes a manifold positioned between the wellhead and the plunger catcher. The manifold includes a plunger passageway that extends from the bottom of the manifold to the top of the manifold, with the plunger catcher being mounted to the top of the manifold. The manifold also includes a production passageway through which oil or gas leaving the wellhead is routed. A choke mechanism for at least partially blocking the production passageway is provided on the manifold to selectively vary the volume of the oil or gas leaving the wellhead that is routed through the plunger catcher. This, in turn, can selectively vary a force imparted to a plunger by the oil or gas leaving the wellhead to ensure the plunger is fully seated in the catcher when it arrives at the wellhead.

What is claimed is: 
     
         1 . A choke mechanism for an oil or gas well manifold, comprising:
 a choke mount configured to be attached to an exterior surface of an oil or gas well manifold that includes a choke passageway that extends from the exterior surface to a production passageway within the manifold, wherein the choke mount is configured to be attached to the exterior surface of the manifold such that the choke mount surrounds or covers the choke passageway;   a choke member that is movably mounted in an internal bore of the choke mount, the choke member including a proximal end and a distal end; and   a choke actuator that includes:
 an actuator housing that is removably attached to the choke mount; 
 an electric motor having a rotating shaft, the electric motor being mounted to the actuator housing; and 
 a drive mechanism comprising a cam that is attached the rotating shaft of the electric motor, wherein the cam is operatively coupled to the proximal end of the choke member such that rotation of the cam by the electric motor causes the choke member to move in a longitudinal axial direction along the internal bore of the choke mount. 
   
     
     
         2 . The choke mechanism of  claim 1 , wherein when the choke mount is attached to an exterior surface of a manifold of an oil or gas well such that the choke member is received in a choke passageway of the manifold, the choke actuator can be used to cause the choke member to move along the choke passageway between a retracted position at which the distal end of the choke member does not substantially protrude into a production passageway of the manifold and an extended position at which the distal end of the choke member protrudes into the production passageway to at least partially block the production passageway. 
     
     
         3 . The choke mechanism of  claim 1 , wherein the drive mechanism further comprises a cam follower that is interposed between the cam and the proximal end of the choke member. 
     
     
         4 . The choke mechanism of  claim 1 , wherein rotation of the cam by the electric motor causes the choke member to move in a first longitudinal axial direction along the internal bore of the choke mount, the choke actuator further comprising a biasing member mounted on the actuator housing and operatively coupled to the choke member such that the biasing member urges the choke member in a second longitudinal axial direction along the internal bore of the choke mount, the second longitudinal axial direction being opposite the first longitudinal axial direction. 
     
     
         5 . The choke mechanism of  claim 4 , wherein when the choke mount is attached to an exterior surface of a manifold of an oil or gas well such that the choke member is received in a choke passageway of the manifold, the electric motor can be used to cause the choke member to move in the first longitudinal axial direction along the choke passageway to an extended position at which the distal end of the choke member protrudes into a production passageway of the manifold to at least partially block the production passageway, and wherein the biasing member can cause the choke member to move in the second longitudinal axial direction along the choke passageway to a retracted position at which the distal end of the choke member does not substantially protrude into the production passageway. 
     
     
         6 . The choke mechanism of  claim 4 , wherein rotation of the cam in a first rotational direction causes the choke member to move in the first longitudinal axial direction along the internal bore of the choke mount against a biasing force of the biasing member, and wherein rotation of the cam in a second rotational direction opposite the first rotational direction permits the biasing member to cause the choke member to move in the second longitudinal axial direction along the internal bore of the choke mount. 
     
     
         7 . The choke mechanism of  claim 4 , wherein the biasing member is a coil spring. 
     
     
         8 . The choke mechanism of  claim 7 , wherein at least a portion of the coil spring surrounds at least a portion of the proximal end the choke member. 
     
     
         9 . The choke mechanism of  claim 8 , wherein the drive mechanism further comprises a cam follower that is interposed between the cam and the proximal end of the choke member, and wherein an end of the coil spring bears against an end of the cam follower. 
     
     
         10 . A choke mechanism configured to be attached to an exterior surface of an oil or gas well manifold that includes a choke passageway that extends from the exterior surface of the manifold to a production passageway within the manifold, the choke mechanism comprising:
 a choke mount that is configured to be attached to the exterior surface of the manifold;   a choke member that is movably mounted in an internal bore of the choke mount, the choke member including a proximal end and a distal end; and   a choke actuator coupled to the proximal end of the choke member, the choke actuator including:
 an actuator housing that is removably attached to the choke mount; 
 an electric motor having a rotating shaft, the electric motor being mounted to the actuator housing; and 
 a drive mechanism comprising a cam that is operatively coupled to the rotating shaft of the electric motor and the proximal end of the choke member such that rotation of the cam by the electric causes the choke member to move in a longitudinal axial direction along the internal bore of the choke mount, 
   wherein when the choke mount is attached to the exterior surface of the oil or gas well manifold such that the choke mount surrounds or covers the choke passageway of the manifold, the choke member is located in the choke passageway of the manifold, and wherein the choke member can move in the longitudinal axial direction between a retracted position at which the distal end of the choke member does not substantially protrude into a production passageway of the manifold and an extended position at which the distal end of the choke member protrudes into the production passageway to at least partially block the production passageway.   
     
     
         11 . The choke mechanism of  claim 10 , wherein rotation of the cam by the electric motor causes the choke member to move in a first longitudinal axial direction along the internal bore of the choke mount, the choke actuator further comprising a biasing member mounted on the actuator housing and operatively coupled to the choke member such that the biasing member urges the choke member in a second longitudinal axial direction along the internal bore of the choke mount, the second longitudinal axial direction being opposite the first longitudinal axial direction. 
     
     
         12 . The choke mechanism of  claim 10 , wherein the drive mechanism further comprises a cam follower that is interposed between the cam and the proximal end of the choke member. 
     
     
         13 . The choke mechanism of  claim 1 , wherein rotation of the cam between 0° and 180° in a first rotational direction causes the choke member to move in a first longitudinal axial direction toward the extended position. 
     
     
         14 . The choke mechanism of  claim 13 , wherein the choke actuator further comprises a biasing member that is operatively coupled to the choke member and that biases the choke member toward the retracted position. 
     
     
         15 . The choke mechanism of  claim 14 , wherein rotation of the cam in the first rotational direction between 180° and 360° allows the biasing member to cause the choke member to move in a second longitudinal axial direction toward the retracted position. 
     
     
         16 . The choke mechanism of  claim 14 , wherein rotation of the cam in a second rotational direction opposite the first rotational direction between 180° and 0° allows the biasing member to cause the choke member to move in a second longitudinal axial direction toward the retracted position. 
     
     
         17 . The choke mechanism of  claim 10 , wherein the choke actuator further comprises a biasing member that is operatively coupled to the choke member and that biases the choke member toward the retracted position, wherein rotation of the cam in a first rotational direction causes the choke member to move in a first longitudinal axial direction along the internal bore of the choke mount against a biasing force of the biasing member, and wherein rotation of the cam in a second rotational direction opposite the first rotational direction permits the biasing member to cause the choke member to move in the second longitudinal axial direction along the internal bore of the choke mount. 
     
     
         18 . The choke mechanism of  claim 17 , wherein the biasing member is a coil spring. 
     
     
         19 . The choke mechanism of  claim 18 , wherein at least a portion of the coil spring surrounds at least a portion of the proximal end the choke member. 
     
     
         20 . The choke mechanism of  claim 19 , wherein the drive mechanism further comprises a cam follower that is interposed between the cam and the proximal end of the choke member, and wherein an end of the coil spring bears against an end of the cam follower.