Differences Between Cement Retainers and Bridge Plugs

Drilling & Milling Best Practice:

If the situation is to perform drilling or milling operations (junk mill), the recommended practice is as follows:

• Use a tricone Bit(IADC Bit Codes 2-1, 2-2, 2-3, 2-4, and 3-1) – medium hard formation. PDC Bit is not preferred.
• The best RPM shall be – 70 to 125
• Use a mud viscosity of 60 CPS for cuttings removal
• Weight on bit – Apply 5-7 Klbs. Until the top end of the mandrel is drilled away, which is 4-5 inches. Then increase 3 Klbs. of weight per inch of bit size to drill the remaining part. Example: 4-1/2 bit will use 9,000-13,500 lbs. of weight.
• Don’t apply weight over the recommended amount. Unreasonable weight can tear out chunks of the Bridge Plug, and performing another trip will be mandatory to remove the chunks to permit further penetration.
• Drill Collars– shall be used to supply the necessary WOB and Drilling bit Example: 4-1/2 thru 5-1/2 (8 min.) 7 and larger (12 min.).
• Junk Baskets– One or more junk baskets shall be used in the drill string. If reverse circulation is planned, any tools in the tubing or drill string should have the same ID of the bit so cuttings will not bridge.
• Annular Velocity– 120 ft/min is to be considered.
• Junk basket above the bit.

Tools Required For Setting and Servicing

• Wireline Adapter Kit
• Stinger Seal Assembly
• Tubing Centralizer
• Mechanical Setting Tool
• Wireline Adapter Kit for Flapper Bottom
• Hydraulic Setting Tool

Bridge Plug Setting & Releasing Mechanisms

Indeed, the setting and retrieving mechanisms shall differ from manufacturer to manufacturer. But, we introduce a general procedure for you to get the idea.

Tension Set

Run to the required depth while latched to its retrieving tool.

Pick up, rotate XX (1/4) turn to the right at the plug, and lower the tubing to set lower slips.

Pull sufficient tension to pack-off elements, slack off, and then pick up again to ensure plug setting (15,000 to 20,000 lbs).

After setting the plug, slack off the tubing weight, hold the left-hand torque, and pick up to free the running tool from the plug.

Compression Set

Run to the required depth while latched to the retrieving tool.

Pick up, rotate XX (1/4) turn to the right at the plug, and lower the tubing to set lower slips.

Slack off adequate weight to pack-off elements, then pick up to firmly set upper slips and slack off again (15,000–20,000 lbs).

After setting the plug, slack off the tubing weight, hold the left-hand torque, and pick up to free the running tool from the plug.

Releasing Procedure

Lower tubing until the retrieving tool tag on the bridge plug and latches on the same.

Circulate to wash out the sand from the plug slips.

Open the bypass valve by slacking off weight, hold right-hand torque, then pick up.

Wait for pressure equalization.

Pull upward to release the slips, relax packing elements, and re-latch.

The plug may now be free to move.

If the plug will not release conventionally, slack off, re-set, then pull up to shear J-pins and release the plug (J-pins will shear at 40,000 to 60,000 lbs each).

Once you succeed in shearing the pins, the tool won’t be able to move downhole.

Important Features For Bridge Plug To Think About

Many bridge plugs come with a large internal by-pass to minimize the swabbing effect of RIH & POOH. This bypass opens before releasing the plug to make a pressure equalization. Some BPs also have the ability to set and pack off the element in tension.

The drillability of the tool also should be considered to save time and cost of the operations.

Some tools come with the feature of converting to cement retainer or from mechanical set to wireline set.

Good clearance between the bridge plug and casing must be considered also to have fast and safe running operations without sudden set.

There are some designs that prevent movement due to opposed slips. This feature ensures that there will be no movement in case the differential pressure increased in and direction (upward or downward).

Bridge plugs are essential downhole tools used in oil and gas operations for pressure equalization, temporary abandonment, and zonal isolation. There are several types of bridge plugs available to suit a variety of applications. Each type has its own unique characteristics and benefits which make it suitable for certain types of operations. Using the right type of bridge plug can significantly reduce rig time and ensure successful pressure tests.

If you are interested in Vigor's bridge plug series products, please do not hesitate to get in touch with us to get the most professional products and the best quality service.

For more information, you can write to our mailbox info@vigorpetroleum.com & marketing@vigordrilling.com