A variety of servicing tools play fundamental roles in wellbore isolations and completions. It’s easy to confuse one for the other, but with a little understanding, you can choose the correct tool and perform a task safely and efficiently. We’ll help you understand the difference between cement retainers and bridge plugs to ensure you make the proper selections.
A Closer Look at Cement Retainers
Cement retainers are isolation tools set in the casing or liner that enable treatments to be applied to a lower interval while providing isolation from the annulus above. Cement retainers are typically used in cement squeeze or similar remedial treatments. A specially profiled probe, known as a stinger, is attached to the bottom of the tubing string to engage in the retainer during operation. When the stinger is removed, the valve assembly isolates the wellbore below the cement retainer.
Two instances of cement retainers in the oil and gas industry include wellbore abandonment and casing repair. Wellbore abandonment uses cement retainers to squeeze cement into a lower zone while isolating above the cement retainer. This allows cement to be spotted directly into the zone and squeezed to ensure a proper seal, preventing any further hydrocarbon migration into the wellbore. Casing repair uses cement retainers to repair leaks, holes, or splits into the casing by isolating the above wellbore and allowing cement to be spotted directly into the casing needing repair. It holds the cement in this area until it has performed a seal and hardened. The cement retainer and remaining cement left in the wellbore can easily be removed with conventional drilling operations.
Functions of a Bridge Plug
The drilling bridge plug is used for zonal isolation, sealing a lower zone from either an upper zone or isolating the wellbore completely from the surface equipment. Operators can set the bridge plug in multiple different ways, including wireline set, hydraulicly set, hydro-mechanical set, and full mechanically set.
Operators can use three bridge plugs: a wireline set, a hydro-mechanical set, and a fully mechanical set. One of the best ways to ensure optimal setting and accuracy is to combine the plug with a packer.
The Core Differences
The core differences between cement retainers and bridge plugs are in their primary intentions per the application demands. While a cement retainer assists in remediation and squeeze operations, a bridge plug isolates the wellbore’s upper and lower zones and is permanently or temporarily placed. Another notable difference is retainers allow the operators to open and close a valve, enabling them to perform squeeze operations below them. Bridge plugs seal off complete access to the wellbore or below them.
Silver Fox Products
Silver Fox is the premier supplier of high-quality and industry-leading servicing tools. We carry various bridge plug mechanisms to support all forms of well completions and servicing demands. Partner with us today to learn more about our comprehensive catalog and available distribution processes.