Vol. 226 No. 12

Rig Floor Equipment

Dual elevator system increases efficiency and safety

The Dual Elevator System (DES) is one of Blohm + Voss’ latest pipe handling innovations. This tool is beneficial for advanced rig design on deep drilling rigs and in difficult drilling conditions. The system uses two automatic, hydraulic-operated elevators for standard drilling operations, such as tripping and drilling, etc. It is remote-controlled and can be operated by one person from the driller’s cabin.

The elevators are used for both slip and elevator functions, eliminating regular slips. For example, one elevator is placed at the well center (slip function), while the other is picking up or releasing a stand. The bail connection and disconnection function is completely hands-free.

Blohm + Voss’ Dual Elevator System uses two automatic, hydraulic-operated elevators for standard and is remote-controlled from the driller’s cabin.

Each elevator has two hydraulic connections. One is located at the ear side, and one at the rear side. The ear side connection can be connected to the bails (elevator links). Therefore, the elevator can be operated while hanging in the bails. The rear hydraulic connection operates the elevator at the skid system on the drill floor. For connection and disconnection of the bails, a link spreader system has to be attached to the top drive.

On the drill floor, one elevator can be placed on the well center and the second elevator is at the parking position behind the well center. The system is able to move one elevator from the well center to the parking position and back through a hydraulic skid system. If the system is not needed, it can be removed into a storage position by using four integrated transport rollers.

Components

The DES consists of a base plate, two elevators of type VES-SD 750, one set of elevator links 4-3/4 in. x 144 in. and the automatic coupling device. The base plate is attached with five centering pins to the drill floor. Guide rails and slide rails are arranged on the base plate on which the elevators can move. The positioning switches are integrated in one of the guide rails, which signal the elevator positions: well center or retracted.

The traversing system with the sledge and moveable cylinder, and the rear coupling system for the hydraulic connection, are built onto the base plate. The entire operation and control hydraulics are located under stable protective enclosures on the base plate. On the side next to the base plate there are four transport rollers, which can be hydraulically extended. The operation is done from the rear-end wall.

The automatic coupling system is permanently connected to the elevator links. The system uses hydraulic signals for feedback, showing whether the doors and latches are closed, the location of the elevator and whether the elevators are connected or disconnected.

The system has a safe working load of 750 short tons and can handle drillpipe, drillcasing or production casing, ranging from 2-3/8 in. to 9-7/8 in. Special pipe and sizes can be accommodated upon request. Gross system weights are: 625 kg for the basic plate, 1,800 kg for each elevator, and 500 kg for the link connection. Materials and manufacturing are in accordance with API 8c.