Understanding Emissions: Offshore Oil

Aerial surveys of production platforms in the Gulf of Mexico have measured emissions at twice the previously estimated climate warming impact. Researchers conducted platform overflights to measure both carbon dioxide and methane emissions and combined that data with field survey information. They concluded that older platforms near shore, usually shallow water platforms used as hubs for oil and gas collection, are the culprits, releasing higher than expected levels of vented methane.

Assessing “carbon intensity” based on types and volumes of greenhouse gasses released will allow a clearer picture of a production site’s environmental impact.

Offshore facilities account for nearly a third of global oil and gas production, but their locations make evaluating emission difficult.

Measuring Methane

Infrared imaging cameras on aircraft let researchers “see” methane plumes that were previously undetectable. Federal agencies are working on regulations and monitoring to help detect unreported methane venting and releases. For measuring surface-level emissions, researchers can use methane isotope readers, spectrometers, and other tools. As technology develops and methane emissions regulations tighten, leak detection and measurement will become more precise.

Flight Hazards

Methane gas may lead to engine failures in helicopters as they operate on and around platforms. As the untreated methane has no odor, the platform and flight crews are unaware of methane levels. Detection systems, in use in the UK and Norway, alert the crews when methane gas levels may pose a flight risk.

Offshore Abandonment

In addition to unexpectedly high methane emissions from operating production platforms, there are potentially thousands of abandoned wells in the Gulf of Mexico seabed. Not all these offshore wells are plugged once it is determined that they are no longer productive or financially viable.

Based on data from the Bureau of Ocean Energy Management (BOEM) and the Bureau of Safety and Environmental Enforcement (BSEE), there are over 55,000 offshore wells in federal U.S. waters, and 97% of them are in the Gulf of Mexico. Just over half – about 28,000 – are permanently abandoned or closed, may not be properly plugged, and not regularly inspected or monitored. As companies change ownership, recordkeeping of well site conditions may become difficult and as barrier equipment degrades, the likelihood of emissions in increases when wells were not effectively plugged and sealed.

Plug and Play

While offshore oil and gas production is a national benefit, maintaining a healthy climate and clean oceans mean that offshore production facilities need to plan for measuring methane (and other greenhouse gasses) and for remediating leakage and preventable venting, even miles from shore. Companies that plan for and take corrective action to stay ahead of regulations will benefit both the climate and their bottom line.