Composite Plug Milling System
6 - 8 weeks
Milling out composite bridge and frac plugs with hydraulically driven workover motors is the most common method of removal. This can be done while the wellhead is still under pressure by using either coiled tubing or a snubbing unit. This procedure applies specifically to coiled tubing mill outs, but many of the tools and best practices apply to snubbing unit mill outs as well.
System includes the following:
- Coiled Tubing Connector
- Dual Flapper Back Pressure Valve
- Hydraulic Disconnect with 5/8" Drop Ball
- Dual Circulation Sub with 1/2" Drop Ball
- Baker Hughes Mud Motor with D Stator
- Mill or Vanguard Bit (4-1/2" or 4-5/8" Diameter)
- Coiled Tubing Connector
Coiled tubing connectors provide a means of attaching a tool string to the end of the coiled tubing. The connectors, when installed correctly, provide a reliable, strong sealed connection to the coiled tubing. All of the connectors have been designed with either a fishing neck or a slick profile on the OD of the top sub. This will accommodate standard external fishing overshots should the need arise. Coiled tubing connectors have been designed for most sizes of coiled tubing. The coiled tubing connectors are of the slip type or collet type design. The slip type connectors are also equipped with set screws to rotationally lock them from spinning when used in conjunction with tools that create torque such as coiled tubing workover motors.2-3/8" PAC DSI connection.
- Back Pressure Valve
The back pressure valve is a flapper-type valve that allows fl ow down the tubing, but stops flow coming back up the tubing. The back pressure valve has two flappers and flapper seals. The second flapper is redundant to the first and can be run where redundant seals are required. The flapper is designed so that a ball can be pumped through it at minimum fluid flow rate.
The back pressure valve is normally run directly below the coiled tubing connector in CT operations and at the top of the BHA in snubbing operations. The back pressure valve is run as a well control measure to prevent wellbore pressure from entering the workstring. No pipe manipulation or pressurization sequence is required to operate the tool.2-3/8" PAC DSI connection.
The FAU™ safety hydraulic disconnect is specially designed for thru-tubing fishing operations, and is built to withstand high tensile and torsional stresses encountered in jarring and motor applications. The FAU safety hydraulic disconnect may be run anywhere in the string as long as the actuation ball can be circulated to it. When disconnected, a GS fishing profile remains, and subsequent retrieving operations may continue with the hydraulic releasing GS spear.2-3/8" PAC DSI connection and 5/8" drop ball.
- Ball Operated Circulating Valve
The circulating valve provides a large area circulation path between the coiled tubing ID and the annulus. The circulation ports are opened by dropping a ball to its seat in the valve and applying pressure in order to shear some shear screws and move a piston downwards. Once the valve has been opened the ball and seat seal in the mandrel ID below the ports effectively blocking off any further fluid bypass to below. This feature allows for the use of the valve for the spotting of fluids above a set inflatable packer with the knowledge that all fluids are being directed out of the circulating valve and not to below the packer.
Applications for the circulating valve include chemical treatments above a set packer, cement placement above a permanent bridge plug, debris barrier placement above a retrievable bridge plug, etc. The tool may be supplied with an integral rupture disc port for use when dropping a ball may not be possible, i.e., in a plugged situation. Here the rupture disc may be over pressured in order to achieve circulation in order to allow further use of drop balls.2-3/8" PAC DSI connection and 1/2" drop ball.
- Workover Mud Motor
The Baker Hughes Navi-Drill™ series is a positive displacement motor (PDM) used as a downhole drive mechanism in milling, drilling or cutting operations.Maximum Temperature 265°F (130°C) .
- Mill or Bit
Available in 4.5" OD Superloy or Opticut, 4.625" Superloy or Opticut or 4.625" Steeltooth Tricone.
Opti-Cut: These cutters are designed to act much like Superloy, but are no longer randomly shaped. Each piece has identical geometry optimized so that no matter how the cutter is placed on the body of the cutting or milling tool there is always a sharp cutting edge and/or point looking up. As the cutter is worn down, new cutting edges and points are exposed. The new cutter has a total of sixteen cutting points and eight cutting edges.
Superloy: This material is made of crushed sintered tungsten carbide particles that are suspended in a special copper based brazing-type alloy with a high nickel content. Tungsten carbide is the finest milling material available for downhole steel cutting or milling tools.
Vanguard Steeltooth Tricone Drillout Bit: Designed to do more than simply drill through composite bridge plugs (CPBs), the Baker Hughes Vanguard™ plug drillout roller cone bit consistently delivers a cleaner, more reliable drillout operation. Click here for more info.