A similar approach is taken in the United States where inspection frequency and repairs timeframes differ according to the nature of the facility and specific LDAR activity. For example, quarterly audio, visual, and olfactory (AVO) monitoring surveys are required at small well sites and sites with a single wellhead. If a leak is detected, an initial attempt at repair must be made within 15 days after detecting fugitive emissions, and the repairs must be completed within 15 days after first attempt. For multi-wellhead sites (without major production and processing equipment), quarterly AVO monitoring surveys are required and if leaks are detected, initial attempt at repair must be made within 15 days, and repairs must be completed within a further 15 days. In addition, semi-annual optical gas imaging (OGI) surveys are required. Should a leak be detected, an initial attempt at repair must be made within 30 days after detecting fugitive emissions, and the repairs must be completed within 30 days after first attempt (EPA, 2023[9]).
In Canada, the 2018 Canadian federal regulations require inspections at least three times per year and at least 60 days after a previous inspection. This requirement (to limit inspection to three times per year), reflects the environment of the Canadian upstream oil and gas sector where LDAR inspections are not possible in offshore and arctic locations during winter months (IEA, 2021[4]). A release of hydrocarbons from an equipment component is considered a leak if the release consists of at least 500 parts per million by volume (ppmv) of hydrocarbons, as determined by an inspection conducted by means of an eligible portable monitoring instrument in accordance with EPA Method 21.4 If a LDAR inspection identifies an actionable leak, a repair must be made within 30 days if the repair can be carried out while the equipment component is operating, or if not, during the next planned shutdown.
In Colombia, article 42 of the 2022 Colombia methane regulations provides that the operator must carry out LDAR activities at its oil and gas facilities. Although there is an exemption for facilities that operate with a potential for emissions or leaks of less than 60 000 standard m3 per year. Inspections are required twice per year, and a leak is successfully repaired when it is reduced to less than 500 ppm or when the instruments used for detection do not detect visible emissions. In Mexico, article 71 of the 2018 Mexico methane regulations directs operators to carry out a LDAR programme for each project on a quarterly basis. The threshold for a leak that triggers a repair obligation in 500 ppm.
In Nigeria, the frequency for LDAR inspections is phased in over three years. In the first year after implementation of the Nigeria methane guidelines, an operator shall conduct one inspection at each facility, in the second year, two inspections are required, and in the third and subsequent years, three inspections are required. A leak is successfully repaired when it is reduced to less than 500 ppm (using EPA Method 21) or when an infra-red camera or any other detection technology approved by the regulator does not detect emissions. Repair obligations differ according to the size of the leak and/or if the component cannot be repaired without a shutdown:
The Nigeria methane guidelines note that if the relevant component is a critical one that cannot be repaired without shutdown, operators shall minimise the leak within one day of detection and repair the leak by the end of the next planned process shutdown or within one year, whichever is sooner.
Regulations may provide exemptions or delays to repair timeframes due to the availability or access to certain equipment or components. For example, in response to supply chain concerns, the U.S. EPA’s Final Rule to Reduce Methane and Other Harmful Pollution from Oil and Natural Gas Operations allows operators additional time to repair fugitive emission components if a replacement is required but parts cannot be acquired or installed due to the following conditions:
Replacement valve supplies have been sufficiently stocked but are depleted at the time of the repair
Replacement fugitive emissions component (or a part) requires custom fabrication (EPA, 2023[9]).