A review of close-range and screening technologies for mitigating fugitive methane emissions in upstream oil and gas

Abstract

Fugitive methane emissions from the oil and gas industry are targeted using leak detection and repair (LDAR) programs. Until recently, only a limited number of measurement standards have been permitted by most regulators, with emphasis on close-range methods (e.g. Method-21, optical gas imaging). Although close-range methods are essential for source identification, they can be labor-intensive. To improve LDAR efficiency, there has been a policy shift in Canada and the United States towards incorporating alternative technologies. However, the suitability of these technologies for LDAR remains unclear. In this paper, we systematically review and compare six technology classes for use in LDAR: handheld instruments, fixed sensors, mobile ground labs (MGLs), unmanned aerial vehicles (UAVs), aircraft, and satellites. These technologies encompass broad spatial and temporal scales of measurement. Minimum detection limits for technology classes range from <1 g h−1 for Method 21 instruments to 7.1 × 106 g h−1 for the GOSAT satellite, and uncertainties are poorly constrained. To leverage the diverse capabilities of these technologies, we introduce a hybrid screening-confirmation approach to LDAR called a comprehensive monitoring program. Here, a screening technology is used to rapidly tag high-emitting sites to direct close-range source identification. Currently, fixed sensors, MGLs, UAVs, and aircraft could be used as screening technologies, but their performances must be evaluated under a range of environmental and operational conditions to better constrain detection effectiveness. Methane-sensing satellites are improving rapidly and may soon be ready for facility-scale screening. We conclude with a speculative discussion of the future of LDAR, touching on integration, analytics, incentivization, and regulatory pathways.

Aerial and ground-based optical gas imaging survey of Uinta Basin oil and gas wells

“…Cold ambient temperature leads to poorer contrast between the plume and the background (Ravikumar et al, 2016). Fox et al (2017) and Fox et al (2019) discussed the problem of poor optical gas imaging detection during winter months due to cold temperatures. More plumes were detected per pad at the lowest wind speeds, likely because of decreased plume dilution (Ravikumar and Brandt, 2017), though this trend was inconsistent across the range of observed wind speeds.…”

Repeated leak detection and repair surveys reduce methane emissions over scale of years

“…These policies typically include a combination of absolute limits on venting and periodic leak detection and repair (LDAR) programs to detect and mitigate fugitive emissions or leaks [15,16]. While many technologies have been recently developed to detect methane emissions, most regulatory LDAR programs require the use of optical gas imaging (OGI) systems for leak detection [17][18][19]. While OGI-based LDAR programs have been found to be effective in a survey of operators, there has been no systematic study of the effectiveness of repair process and the persistence of emissions reductions from one survey to the next in real-world operating conditions [20].…”

A methane emissions reduction equivalence framework for alternative leak detection and repair programs

“…Although effective, these approved methods remain labour-intensive (ICF International, 2014, 2015. Recently, new methane-sensing technologies have emerged, promising faster, cheaper, or more effective leak detection (Fox et al, 2019). In response, regulators in Canada and the U.S. have created opportunities for flexible LDAR programs that permit new approaches to detection.…”