Coiled Tubing Conveyance Tool
WWT International Coiled Tubing Services developed WWT Coiled Tubing Tractors™ (CT Tractors) to help coiled tubing operators overcome the problem of CT lockup in complex, extended reach wells. Our patented, all-hydraulic Tractors with ball drop and e-line pass through ability enable you to deploy equipment further and faster than with CT alone to cost-effectively reach your target depth, while performing various operations in a wide range of cased or open-hole wellbore sizes. Our lighter, smaller WWT 212 Coiled Tubing Tractor™ was specially designed with our field-proven Tractor technology for small-diameter well sections.
The WWT CT Tractor has greater pulling power than any tractor on the market. Our record-breaking performances back this up. The Model 470, for example, delivers 14,500 pounds of carrying capacity, with varying capacities for our other models. Operational Ranges of WWT CT Tractors Click to open Tractor Specifications
Designed for Ultimate Flexibility
Several innovations make the WWT CT Tractor the most versatile, powerful Tractor available:
- Special patented positive grippers enable them to deploy heavy tool strings to the outer zones of extended reach wells. This debris-tolerant design provides continuous traction in a wide range of cased or open-hole wellbore sizes without damaging the casing or formation.
- Exclusive thru-bore design offers ball-drop or e-line pass through flexibility for tools positioned ahead of the Tractor and facilitates fluid flow.
- All-hydraulic operation and controls (no E-line required) so they deliver increased reliability during extended in-well service.
- Tough non-magnetic, acid-resistant Inconel®/beryllium copper construction can withstand harsh downhole environments.
- Compatible with almost all intervention fluids
The innovative fail-safe grippers, combined with a unique thru-bore design, makes WWT CT Tractors ideal for:
- Perforating (Pressure Pulse- or Ball Drop Fire-Compatible)
- Wellbore Cleanout
- Equipment Recovery
How It Works
The Tractor consists of two gripper and piston assemblies – one on the front and one at the back. A control unit, positioned between the assemblies, diverts fluid to each assembly in a synchronized manner. Operation is simple and uses procedures and controls that are already familiar to a CT operator. To start the Tractor, the operator increases fluid flow until the pressure to the Tractor exceeds a predetermined set point.
Pressurized fluid is distributed to the forward gripper, which causes it to expand and engage the wellbore. A piston is activated and drives the Tractor forward, pulling the coiled tubing and pushing the downhole equipment ahead of it. This sequence is then repeated, activating the second assembly. (One assembly engages as the other disengages.) The resulting motion is similar to that of an inchworm, providing continuous forward movement without damaging the casing or formation. The Tractor will travel at the maximum speed with the maximum pulling force possible for the available differential pressure. The rate of advancement down the wellbore is controlled by the rate of feed from the coiled tubing injector.
To perform various applications that require fluid pressure, the Tractor simply needs to be turned off. Tractor operation can be interrupted at any time by reducing the fluid pressure below the Tractor’s operating set point. Once the Tractor is off, fluid flow at any pressure can be directed to the tool string to perform the required application. Restarting the Tractor is a simple matter of reducing the fluid pressure to zero then increasing it beyond the Tractor's operation set point. At any time the operator can turn the Tractor off and retract the coil to retrieve the tool string out of the hole.