Ideally, wireline cable should be spooled off the drum and back onto the drum at the same tension. However when the wireline is coming up-hole the line tension is much greater than when it is going down-hole. The Powered Capstan is positioned between the hole and the main winch to handle the main hoisting work. This allows constant tension between the capstan and the main winch drum. A controlled target tension on the main winch is delivered regardless of which direction the cable is running.
The Power Capstan can give up to 9,000 lbs hoisting assistance which allows standard winch units to be used beyond their normal operating range and removing the need for custom winches. The Powered Capstan automatically maintains a screen selected "TARGET" tension on the main winch with the cable running in either direction. The Powered Capstan thereby eliminates “cable crush” on the drum.
A typical 4,000 lbs target can be maintained on the winch whether the actual well tension is 13,000 lbs when hoisting, or only 200 lbs when running cable down-hole into the well.
The system is fully automatic and controls synchronize the movement of the capstan and the main winch as determined by winch operator. The system allows speeds up to 300 ft/min and can run multiple tools.
The capstan can be used either secured to the horizontal deck or supported vertically in the derrick by the elevators.
The capstan is designed for minimal maintenance needs. The steelwork has 10-year corrosion protection.
The entire units is a 3-part lift, all with DNV 2-7.1 certification. The capstan and power pack are both rated Zone 2.
• Operator friendly package design
• Adds to wireline safety as all high tensions are contained in the derrick
• Allows deep-deviated high-tension wells to be managed
• Advantage over other conveyance methods
• Improves cable life
• Reduces conductor failure
• Eliminates cable crush
• Cable head can be retained for speedy rig up
• Reduces rig down time
• Improves productivity
• Reduces operating cost
• Reduces drum stress
Choice of Zone 2 or non-hazardous
Optional electric or diesel prime movers
Optional Zone 2 and non hazardous certification
Detachable 50-ft or 100-ft hydraulic hoses
Fitted with 200-ft multi-core control cables
Programmable Logic Controller (PLC) allows selection of "TARGET" tension
PLC automatically maintains the winch at the selected "TARGET" tension
PLC maintains "TARGET" tension irrespective of cable direction and well tension
Winch operator can alter "TARGET" tension while running the job (within design parameters)
Operator friendly screen displays all required parameters
Analog and digital presentation for operator
Screen options provide six control modes and preferred displays
Alarms, sounder, settings menu, instrumentation and manual stop control of power pack
The control options allow the program to compute using
- well signal only
- combined well and winch signals
- just the winch signal only
Provided with its own transit case - normally ships in the hose baske
The main benefits provided by this device are:
1. Reduces spooling tension to help alleviate cable crush
2. Reduces drum loading to help prevent drum failures
3. Can be operated going into and out of the well to maintain wireline spooling profile
4. Torque unit replaces top sheave and reduces load on rig up equipment
5. Provides additional line pull to assist hoist unit
• Operator friendly package design
• Adds to wireline safety as all high tensions are contained in the derrick
• Allows deep deviated high tension wells to be managed
• Advantage over other conveyance methods
• Improves cable life
• Reduces conductor failure
• Eliminates cable crush
• Cable head can be retained for speedy rig up
• Reduces rig down time
• Improves productivity
• Reduces operating cost
• Reduces drum stress
The entire units is a 3 part lift, all with DNV 2-7.1 certification.