Well systems are designed to connect high-pressure oil or gas in deep underground reservoirs to surface flowlines securely with full containment. Rigorous industry standards necessitate the presence of at least two ‘integrity barriers’ between produced fluids and the environment outside of the well system. Occasionally, one or more barriers can fail allowing fluids to escape, sometimes with dire consequences.

Apart from the major oil leaks that make headlines, some smaller oil and gas leaks can continue undetected for years, especially if they are hidden underground or migrate far from the well system. TGT’s Seal Integrity products are designed to locate even the smallest seal failure anywhere within the well system, enabling precise targeted repair. Used proactively, the same diagnostics can be used routinely to ensure well barriers are intact at all times, reducing fugitive emissions.

Key fact: Methane emissions from upstream oil and gas operations are 1.9 GtCO2e annually

Orphan wells typically have no legal owner and may have been abandoned without undergoing a proper decommissioning or plugging process. Methane or liquid emissions from orphan wells can be significant contaminants, especially when the number of orphan or incorrectly decommissioned wells is thought to be in the millions globally. The burden of responsibility for these wells typically falls with operators, regulators or local government, and permanently sealing them is a top priority.

Validating well barrier status and revealing emission sources downhole inside the well system is the first step in sealing these wells properly. TGT’s Seal Integrity and Tube Integrity surveys are used to achieve exactly that. Precision diagnostic insights inform and guide the decommissioning agent to design and execute an effective plugging programme. This approach is equally applicable for any well decommissioning operation, not just for orphan wells, helping operators to secure them efficiently and cost effectively.

According to the ISO standard for ‘well integrity’ (ISO/TS 16530-2), a typical well system contains 26 potential leak paths that could lead to fluids escaping the well system. This is why the standard calls for a ‘dual barrier’ approach underpinned by routine testing of well barriers. Despite these efforts, oil or other harmful fluids such as hydrogen sulfide (H2S) can sometimes spill to the environment.

In most cases these spills are visible or detected quickly, enabling operators to take urgent action. However, sometimes they may go undetected for months or years because there is no visible warning. An example of this might be oil or gas flowing to and contaminating aquifers. TGT’s Seal Integrity answer products are specifically aimed at locating unwanted fluid flow anywhere within the well system, enabling precise targeted repair. Used proactively, TGT diagnostics can be used to ensure well barriers are intact at all times, reducing the risk of pollution.

Key fact: A typical well system has 26 potential leak points.