The Role of Well Integrity in Plug & Abandonment Operations

Well integrity plays a crucial role in ensuring the safety and success of plug and abandonment (P&A) operations. These operations involve the installation of barriers to seal the wellbore and prevent migration and leakage of formation fluids indefinitely. Failure in well barrier integrity can lead to environmental damage, harm to local communities, and severe legal and financial consequences for the operator.

Understanding Plug & Abandonment

Objective of P&A Operations

When a well is no longer profitable or useful, such as an injection well, operators decide to plug and abandon it. The primary objective of the P&A process is to ensure the well's integrity by creating a permanent barrier system that isolates the wellbore from the formation, preventing fluid migration into groundwater zones or to the surface.

Plug & Abandonment Process

The P&A process begins with assessing the history and condition of the existing well barrier elements and developing a plan to install and verify additional barriers as required. The operator ensures that the plan meets regulatory requirements and industry guidelines and selects a P&A service provider to perform the operations. On-site, the service provider removes any wellbore debris or obstructions before logging the well to assess its condition and identify any potential subsurface leaks or hazards.

Mechanical and cement barriers, such as bridge plugs and cement retainers, are placed at predetermined intervals by the service provider to isolate zones and prevent fluid migration. Cement barriers also provide structural support, prevent corrosion, and reinforce the wellbore. Verification of barrier integrity is done through pressure testing, cement bond logging, temperature surveys, and noise logging. Once the integrity is confirmed, the service provider removes the wellhead and any remaining wellbore components before compiling all documentation into a report for handover to the operator.

The Importance of Well Integrity in Plug & Abandonment

Regulatory Compliance

Well integrity is critical in P&A operations to comply with local regulations, ensure safety, and consider the environment. Regulatory agencies, such as the Bureau of Safety and Environmental Enforcement (BSEE), US Environmental Protection Agency (EPA) , NORSOK D-010 Standard, North Sea Transition Authority (NSTA), and Health and Safety Executive (HSE), provide guidelines and regulations for P&A operations. Operators must obtain necessary permits and engage with regulatory authorities throughout the P&A process to ensure compliance, reduce risks, and manage changes to approved programs.

Safety & Environmental Considerations

Compromised well integrity in plugged and abandoned wells can result in the release of pollutants into the air and water, potentially harming the environment. Formation fluid migration can impact water quality, disrupt ecosystems, and create operational challenges. Well integrity ensures that fluids and gases remain confined within their original formation zones, preventing uncontrolled migration and contamination. Documentation of well abandonment activities can be useful in investigations or troubleshooting in the future.

Barrier Testing & Verification

Importance of Verifying Well Barrier Integrity in P&A Operations

The consequences of barrier integrity failure are significant, affecting public health, safety, the environment, and potentially leading to legal and financial penalties. Verifying barrier integrity is crucial to ensure their effectiveness.

Technologies for Verifying Well Barrier Integrity in P&A Operations

Well integrity relies on the collective performance of all barrier components. Data collected during well construction and cement bond logs can identify channels or voids that may allow fluid migration. Pressure testing and drill pipe weight tests are effective methods to validate cement plug placement and verify the integrity of the barrier system. Pressure testing is the most reliable method and is used to assess the barriers' effectiveness under specific criteria.

Competence in Integrity Monitoring & Inspection of P&A Wells

Qualified professionals with expertise in well integrity management and regulatory requirements should conduct monitoring and inspections to assess the condition of P&A wells accurately.

IPT’s team of subject matter experts provides barrier integrity verification, tracking, and consultation services to support your well integrity program.

Assure Well Integrity During Plug & Abandonment

IPT offers products and services to test and verify the integrity of the entire well barrier system throughout the life cycle of a well, including plug and abandonment operations. Contact us to learn more about how IPT’s products and services can ensure the success of your P&A operations.