Bridge / Frac Plugs

Bridge Plugs & Frac Plugs

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Downhole bridge plugs and frac plugs are essential completion tools used in oil & gas well operations to enable zonal isolation, wellbore integrity, and staged fracturing or abandonment. They allow operators to isolate lower sections of the wellbore, prevent fluid or gas migration, and control which zones are open to production, stimulation or cementing.

 

Why “Bridge Plug” vs “Frac Plug”?

• Bridge Plugs — typically used to isolate the lower portion of the wellbore. They form a barrier above which operations (cementing, testing, perforating, stimulation, abandonment, etc.) may be conducted without affecting the lower zones.

• Frac Plugs — used during multi-stage hydraulic fracturing (plug-and-perf) to isolate each stage as the treatment progresses up the wellbore. After fracturing a zone, a frac plug is set above it so the next zone can be treated independently.

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Types of Bridge Plugs by Setting Mechanism

Downhole bridge plugs come in different setting styles — selected depending on well architecture, operator needs, and whether isolation is temporary or permanent. At PDG we provide the correct solution for our customers’ needs, and through detailed planning can recommend the correct tool for the required application.

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Hydraulic-Set Bridge Plugs

• These plugs are activated by hydraulic pressure (e.g. via coiled tubing, drill-pipe, or hydraulic setting tools) to set slips and expand the sealing element against the casing.

• Well suited for varied well trajectories (vertical, deviated, horizontal) and depths — conveyance methods include coiled tubing, threaded pipe, or wireline/e-line depending on tool design.

• Often used in applications including cementing, zonal isolation, well abandonment, and temporary or permanent plugging operations.

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Mechanical-Set Bridge Plugs

• These plugs are set mechanically — for instance by applying tensile or compressive force (e.g. via coiled tubing or pipe), causing slips to grip and the packing element to seal.

• Mechanical-set plugs are valued for reliability and simplicity, especially in conventional operations where hydraulic setting tools may be unnecessary or undesirable.

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Hydro-Mechanical (Hybrid) Bridge Plugs

• Some designs employ a hybrid “hydro-mechanical” setting mechanism: a hydraulic chamber triggers initial movement, then mechanical action completes the set.

• These plugs combine the advantages of hydraulic-set (ease and flexibility of conveyance) and mechanical-set (robust locking, reliable sealing), and are often “drillable” for later removal or conversion (e.g. to cement retainer).

 

Drillable / Composite Frac Plugs

• Traditional frac plugs may be composite or drillable metal/plastic hybrids. After the fracturing operation, they are milled or drilled out with coiled-tubing-deployed motors and milling tools, restoring full-bore access.

• These are reliable and allow flexibility; however milling operations add time, cost and complexity to completion campaigns.

 

Dissolvable (or Disintegrating) Frac Plugs

• Dissolvable frac plugs are manufactured from specially designed materials (e.g. alloys, degradable elastomeric/sealing components) that degrade over time once exposed to downhole conditions (fluid chemistry, temperature, etc.), such that the plug disappears — eliminating the need for milling.

• This technology accelerates completion, reduces rig time, avoids the need for coiled-tubing milling operations (which may not reach deep or extended-reach wells), and cuts overall cost and risk.

• Dissolvable plugs are increasingly used in modern plug-and-perf operations to maximize efficiency, especially where multiple fracture stages exist, or where full-bore access post-fracture is critical.

 

Key Considerations

• Bridge plugs and frac plugs are fundamental downhole isolation tools, enabling zonal isolation, staged treatments, and safe abandonment.

• The choice between hydraulic-set, mechanical-set, hydro-mechanical, retrievable or permanent plugs depends heavily on well design, casing specifications, expected pressure/temperature, and operations plan (temporary stimulation vs permanent isolation).

• Dissolvable frac plugs represent a modern, efficient solution for multi-stage fracturing: by eliminating milling, they reduce rig time, cost, and operational risk — especially valuable in complex or deep wells.

• Proper plug selection must take into account casing size/grade, downhole conditions (pressure, temperature, chemistry), and whether retrieval or permanent sealing is required.