How do you decommission a well?

1 Planning and preparation

The first step in decommissioning a well is to plan and prepare for the operation. This involves reviewing the well history, design, and status, as well as the regulatory requirements and environmental impact assessment. You also need to identify and mobilize the equipment, materials, and personnel needed for the job, such as a rig, a cementing unit, a wireline unit, and a well control system. Additionally, you need to establish a clear scope of work, a budget, a schedule, and a contingency plan.

2 Isolating the reservoir

The next step is to isolate the reservoir from the wellbore and the surface. This is done by setting cement plugs across the productive zones, the casing shoes, and any potential flow paths. The cement plugs must be designed and placed to ensure adequate length, strength, and integrity. You may also need to perforate, cut, or pull the casing to create a barrier between the reservoir and the annulus. The isolation of the reservoir is verified by pressure testing and logging.

3 Cutting and recovering the wellhead

The third step is to cut and recover the wellhead and any associated equipment, such as the tubing, the christmas tree, and the blowout preventer. This is done by using a rig or a vessel with a cutting device, such as a mechanical cutter, a jet cutter, or an explosive cutter. The cut is made below the mudline or the seabed, depending on the type and location of the well. The wellhead and the equipment are then lifted and transported to the shore for disposal or reuse.

4 Sealing the wellbore

The fourth step is to seal the wellbore at the surface or the seabed. This is done by setting a final cement plug at the top of the wellbore, covering the cut end of the casing. The cement plug must be compatible with the surrounding soil and water, and must prevent any leakage or corrosion. You may also need to install a protective cap or a marker over the cement plug to identify the well location and prevent interference.

5 Restoring the site

The final step is to restore the site to its original or acceptable condition. This involves removing any debris, equipment, or infrastructure from the well location and the surrounding area. You also need to monitor and remediate any environmental impacts, such as soil contamination, water pollution, or habitat disturbance. You may also need to consult with the landowners, the regulators, and the stakeholders to ensure that the site is safe and satisfactory.

6 Decommissioning challenges and tips

Decommissioning a well can be a complex and costly operation, depending on the well characteristics, the location, and the regulations. To address common challenges such as uncertainty about the well status, difficulty in accessing or locating the well, risk of well integrity failure or pressure buildup, lack of available or suitable equipment or personnel, and weather, logistical, or operational delays or disruptions, you need to conduct a thorough and accurate well assessment and data collection. Furthermore, it is important to use the most appropriate and efficient methods and technologies, follow industry standards and best practices, implement a rigorous quality control and safety management system, as well as communicate and coordinate with all the parties involved.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?