What Steps Are Completed During the Plug and Abandon Phase By an Oilfield Service Provider?

As an oil or gas well reaches the end of its productive life, proper plugging and abandonment is required. This careful process seals off the wellbore and prevents any future environmental issues. If you’re curious about what’s involved when a service company plugs and abandons a well, here’s an overview of the typical steps.

Conduct Testing and Prepare the Well

Before permanently plugging a well, initial tests are run to assess its current condition. This includes checking well pressure, perforations, and the cement job. Any issues are repaired to ensure the well is ready for abandonment. Preparation also involves removing any tubing or downhole equipment that could interfere with plug placement.

Set the Bottom Plug

The first plug is set at the very bottom of the wellbore. It seals off the producing zone, so nothing can flow in or out. The bottom plug is typically made of cement pumped down the well. However, mechanical plugs like bridge plugs may also be used. Sufficient cement or mechanical plugs are installed to fully seal the bottom portion of the well.

Place Intermediate Plugs

After the bottom plug, intermediate cement plugs are strategically installed at intervals up the wellbore. This seals off each permeable zone and isolated hydrocarbon-bearing sections. Properly placed intermediate plugs prevent any migration within the well. The number and location of intermediate plugs depends on the well’s specific conditions. More are used in deeper or more complex wells.

Install the Surface Plug

The final step is setting the surface plug across the top portion of the wellbore near ground level. This finishes sealing off the well from end-to-end. Like the other plugs, the material used is most often cement. The surface plug may be reinforced with mechanical plugging devices too. It provides a permanent, impenetrable barrier at the top.

Remove Surface Equipment

Once the wellbore itself is fully plugged, all surface equipment is taken away. This includes the Christmas tree, valves, pipes, tanks, and any other production equipment. The wellhead is removed, and the casing is cut off below the surface. Removing surface equipment eliminates future safety or environmental hazards.

Restore the Land Surface

With the wellbore sealed and equipment taken away, the land around the plugged well is restored. In fields, this may simply involve vegetating any disturbed areas. Around well pads, more extensive reclamation is completed to restore contours, manage drainage, and establish local plants. The goal is returning the site to its natural state.

Test Plug Integrity

Extensive tests are performed to confirm each plug is solidly in place before deeming the well abandoned. Pressure tests check for leaks through the plugs. Other integrity tests analyze the bonding of the cement. If any issues are found, additional plugs are set until results are satisfactory. No well is abandoned until testing verifies complete, long-term isolation.

Submit Regulatory Paperwork

Finally, the oilfield service company completes all required regulatory paperwork. This includes submitting a formal plugging report detailing the specific plugs set and testing results. Permits to officially abandon the well are obtained after regulators review and approve the report. Proper documentation closes out the abandonment process.

Plugging and abandoning oil and gas wells is a meticulous procedure requiring specialized expertise. Each well presents unique considerations too. That’s why this work is left to experienced oilfield service companies, such as Renegade Wireline Services, committed to conducting abandonments in a thorough, environmentally responsible manner. With their help, once-producing wells can be permanently sealed off and retired with confidence.