Vertically folding service arm for a movable platform offshore drilling or servicing rig

An apparatus and method for maintaining electrical and hydraulic connections between a junction box (or junction boxes) located on or near an offshore platform's floor and a movable drilling rig structure are disclosed. The disclosed invention is a unique vertically folding service arm capable of moving in both the horizontal and vertical directions in order to provide enhanced range of movement. The increased range of movement provided by the vertically folding service arm of the present invention allows electrical and hydraulic supply lines to remain connected between a junction box (or boxes) located on or near the platform floor and the rig structure even as the rig structure moves back-and-forth on the platform between multiple well centers. The vertically folding service arm of the present invention can also be easily disconnected and “folded” for transport without requiring the electrical and hydraulic supply lines to be disconnected from the drilling rig structure.

FIELD OF THE INVENTION

The present invention relates to a vertically folding service arm for use on movable platform drilling or servicing rigs used in offshore production of oil and gas reserves. In particular, the invention relates to a unique service arm capable of moving in both the horizontal and vertical directions in order to provide enhanced range of movement that allows electrical and hydraulic supply lines to remain connected between a junction box on or near the platform floor and the rig structure even as the rig structure moves back-and-forth on the platform between multiple well centers.

BACKGROUND OF THE INVENTION

Because of the tremendous expense associated with drilling for oil and gas offshore, oil and gas companies have developed ways to spread the expense associated with manufacturing offshore drilling equipment over a larger number of wells. Typically, in exploring for oil and gas reserves offshore, an exploratory well is drilled with a drill ship or a jack-up rig to determine if the potential oil and gas field is large enough to justify the tremendous expense of manufacturing, assembling, and locating a drilling platform offshore.

If the oil and gas reserves are large enough, a drilling and production platform will be placed over the field. These platforms utilize a movable rig structure that moves back-and-forth along the platform such that multiple wells can be drilled from one platform. After the wells have been drilled, the platform is used to produce oil and gas from these multiple wells.

Over the producing life of the field, it often becomes necessary to perform certain maintenance operations as well as certain stimulation operations aimed at stimulating production from the wells. The drilling rig structure on the platform can be moved over a specific well to perform these servicing operations.

To perform the various operations required of the drilling rig structure, the rig structure must be connected to an electrical power source and a hydraulic fluid supply source. Maintaining connections to these sources, however, has proven difficult in the past with movable drilling rig structures on offshore platforms. Specifically, the prior art “horizontal plane” service arms had a limited range of motion, and, thus, it was difficult to get an extended reach with these horizontal service arms. Often, when using the prior art horizontal service arms, the range of movement of these arms was limited by equipment on the platform and/or drilling rig structure blocking the horizontal service arm from moving in a specific direction. Additionally, preparing the prior art horizontal service arms for transport required disconnecting the electrical and hydraulic supply line connections, thereby increasing the amount of time it takes to prepare the platform for operations once it reaches its offshore destination.

Similarly, prior art “drag chains” suffer from the same limitations as the horizontal service arms. As the name implies, the prior art drag chains are used to drag the supply lines across the platform floor to maintain the connections. Obviously, dragging chains and supply lines across a platform floor that has a significant amount of equipment on it has some limitations. Further, the use of drag chains is a very time consuming process that requires up to a days worth of work to move the supply lines to the drilling rig structures new drilling location. The current invention is designed to alleviate these and other known problems associated with the prior art.

Accordingly, what is needed is a means for maintaining the electrical and hydraulic connections between a junction box or boxes located on or near the platform floor and the drilling rig structure as the drilling rig moves back and forth along the platform. It is, therefore, an object of the present invention to provide a vertically folding service arm capable of moving in both the horizontal and vertical directions in order to provide enhanced range of movement that allows electrical and hydraulic supply lines to remain connected between a junction box located on or near the platform floor and the rig structure even as the rig structure moves back-and-forth on the platform between multiple well centers. It is a further object of the present invention to provide a service arm that can be easily disconnected and “folded” for transport without requiring the electrical and hydraulic supply lines to be disconnected from the drilling rig structure. Those and other objectives will become apparent to those of skill in the art from a review of the specification below.

SUMMARY OF THE INVENTION

An apparatus and method for maintaining electrical and hydraulic connections between a junction box (or junction boxes) located on or near a platform floor and a movable drilling rig structure are disclosed. The disclosed invention is a unique vertically folding service arm capable of moving in both the horizontal and vertical directions in order to provide enhanced range of movement.

The vertically folding service arm of the present invention consists of multiple sections hingedly connected together such that the service arm can “fold” in the vertical plane. The service arm is supported by a rotating support post on one end and utilizes a winch/wireline system that stabilizes the support post by removing the horizontal component of the force acting on the top of the support post so that the weight of the service arm does not tip the post over when the service arm is in operation. On the opposite end, the service arm is connected to the drilling rig structure by a pivoting connector that allows the service arm to move in both the horizontal and vertical planes.

The increased range of movement provided by the vertically folding service arm of the present invention allows electrical and hydraulic supply lines to remain connected between a junction box (or boxes) located on or near the platform floor and the rig structure even as the rig structure moves back-and-forth on the platform between multiple well centers. The vertically folding service arm of the present invention can also be easily disconnected and “folded” for transport without requiring the electrical and hydraulic supply lines to be disconnected from the drilling rig structure.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Referring toFIG. 1, a vertically folding service arm50is shown mounted on the floor15of an offshore drilling and production platform10. As shown inFIG. 1, service arm50is connected to support post70on one end and to the drilling rig structure20(via pivoting connector80) on the other end.

In operation, rig structure20can be moved by sliding it along rails on the platform floor15until rig structure20is over the specific well in which drilling or service operations are to be performed. For larger platforms, drilling and production operations may be conducted on dozens of wells. On these larger platforms, rig structure20can move in both the left and right directions (when looking atFIG. 1) as well as in the forward and backward direction (along the axis extending through the page when looking atFIG. 1). As rig structure20moves back and forth along platform floor15, service arm50allows a range of movement that is capable of maintaining the connection of supply lines94to junction box90and to rig structure20.

Specifically, when rig structure20is located on the well center nearest to junction box90, service arm50is in the “folded” position shown in more detail inFIG. 2. As can be seen inFIG. 2, a first section52of service arm50is connected on one end to support post70via pivoting joint72. In the preferred embodiment of the present invention, support post70rotates to help account for the forward and backward movement of rig structure20, while pivoting joint72allows for the pivoting of service arm50as the service arm is either “folded” or “extended” in the vertical plane due to the movement of rig structure20in the left and right directions. In an alternative embodiment, support post70is stationary, and pivoting joint72is a universal joint that allows for both rotation of service arm50as well as the pivoting of service arm50.

First section52of service arm50is connected to a second section54of service arm50through vertical hinge56. Vertical hinge56allows service arm50to either “fold” or “extend” in response to movement of rig structure20. Second section54is equipped with a winch58and wireline59that are used to stabilize support post70so that the weight of service arm50does not “tip” support post70over during operation. Winch58is controlled such that wireline59exerts a “pulling” force on the top of support post70to counter the horizontal component of the force “pushing” on support post70as service arm50is extended. In this way, the horizontal forces acting on support post70as the service arm50is folded and/or extended can be controlled.

In the preferred embodiment, first section52and second section54of service arm50comprise two parallel sides that can be constructed of standard steel beams. Running between and connecting the parallel sides of service arm50are a series of cable trays or “ladder rung” supports that are used to organize and support the electrical and hydraulic supply lines94carried by service arm50. One of skill in the art will appreciate that service arm50can be made out of any material that has sufficient strength to support the weight of service arm50when extended and the weight of the supply lines94. Further, one of skill in the art will appreciate that the sides of service arm50do not have to be parallel to achieve the objects of the present invention so long as the sides are spaced apart in such a way to allow for cable trays or ladder rung supports to be connected between the sides.

Additionally, first section52of vertically folding service arm50is equipped with a lifting lug53that is designed to receive a wireline from a crane that can be used to lift service arm50for installation or for disconnecting service arm50for storage during transport or during periods of inactivity.

FIG. 2also shows conduit92connected to junction box90on the platform floor15. Conduit92is run from the electrical power source and the hydraulic fluid source located elsewhere on the platform10to junction box90. Supply lines94are run from junction box90through service arm50to the rig structure20. Supply lines94comprise the electrical and hydraulic supply lines that supply power and hydraulic fluid to rig structure20. Conduit92and supply lines94are connected to junction box90through any suitable connection means known in the art.

AlthoughFIG. 2shows a single junction box90, one of skill in the art will appreciate that multiple junction boxes90for the various supply lines94(i.e., for the electrical power supply cables and the hydraulic fluid supply hoses) can be utilized. Regardless of whether one junction box or multiple junction boxes are used, the supply lines94are all run through and supported by service arm50such that they can be connected to rig structure20.

FIG. 3shows service arm50extended outwardly from support post70as rig structure20has moved over a well center further from junction box90. As service arm50is extended, winch58controls the extension of wireline59such that the horizontal force acting on support post70is minimized. Service arm50is capable of extending through the combined action of pivoting joint72, vertical hinge56, and pivoting joint86(connected to pivoting connector80). As service arm50is extended, pivoting joint72and pivoting joint86rotate around their connection points to support post70and to pivoting connector80respectively, while at the same time, vertical hinge56“opens” to allow first section52and second section54to move within the vertical plane. Similarly, the rotation of support post70, in conjunction with the pivoting of pivoting connector80(discussed in more detail with reference toFIG. 4), accounts for the necessary movement of service arm50in the horizontal plane.

Referring now toFIG. 4, to help accommodate the vertical and horizontal movement of service arm50, pivoting connector80is used to connect service arm50to rig structure20. Pivoting connector80is designed to rotate in the horizontal plane. In the preferred embodiment, support beams82are connected to rig structure20such that they extend outwardly from rig structure20at the point where service arm50will be connected. Pivoting connector80is pinned to the support beams82via vertical pins84such that pivoting connector80can rotate about the vertical pins84in the horizontal plane. Service arm50is connected to the pivoting connector80via pivoting joint86that allows service arm50to rotate about the connection point to the pivoting connector80thereby allowing service arm50to move in the vertical plane.

FIG. 4also shows supply lines94carried through service arm50to their connection points along rig structure20. Supply lines94are connected to equipment on rig structure20by any suitable connection means known in the art.

FIG. 5shows service arm50in the stored position. In order to store service arm50during transportation of platform10to its offshore operating position or during periods of inactivity, service arm50can be disconnected from support post70and folded by “closing” vertical hinge56. Supply lines94are disconnected from junction box90and can be placed on service arm50for storage. The opposite ends of supply lines94that are connected to rig structure20do not, however, have to be disconnected. As can be seen inFIG. 5, in the stored position, service arm50is placed on rig structure20such that supply lines94can remain connected to their connection points on rig structure20. By allowing supply lines94to remain connected to the rig structure20when service arm50is placed in the stored position, the amount of time required to install service arm50and to restore the electrical and hydraulic connections between junction box90and rig structure20is significantly reduced.

While the apparatus, compositions and methods of this invention have been described in terms of preferred or illustrative embodiments, it will be apparent to those of skill in the art that variations may be applied to the apparatus and methods described herein without departing from the concept and scope of the invention. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the scope and concept of the invention as it is set out in the following claims.