Methane venting and leaks

Oil and gas producers vent leaked methane from casing cavities to reduce pressure. TGT’s diagnostics can locate the source and flowpaths of rogue gas leaks, ensuring they can be sealed, thereby reducing the need to vent.

Reduce methane venting

Sustained annulus pressure (SAP/SCP) is caused by a build-up of fugitive fluids such as gas in the annular spaces surrounding well system casings. The casings are designed to withstand high pressure but if this pressure is reached, the gas is diverted to the production stream or vented to atmosphere. The global warming potential of methane is ~80x that of CO2, so even small amounts are damaging and must be contained.

 

These rogue fluids reach the annulus via seal failures and flowpaths that begin at hydrocarbon-charged formations and continue towards surface causing a build-up of annulus pressure. TGT’s True Flow and Seal Integrity products can locate the source of annular fluids and trace the flowpaths, enabling well operators to target effective repairs and eliminate SAP-related methane venting.

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Key fact: Methane has 80x higher global warming potential than CO2.

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Key fact: Regulators estimate >3-million abandoned wells in US emit 280 CO2e annually.

Secure orphan and abandoned wells

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.

Reduce fugitive emissions

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.

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