Field inter-comparison of low-cost sensors for monitoring methane emissions from oil and gas production operations

Torres, Vincent M.; Sullivan, David W.; He'Bert, Elyse; Spinhirne, Jarett P.; Modi, Mrinali; Allen, David T.

doi:10.5194/amt-2022-24

“…The source was assumed to be emitting methane at a continuous rate of 10 kg/h. Three sensor detection thresholds were considered: 200, 500, and 1000 ppb above background, representing detection ranges of field-deployed methane sensors, as tested in a sensor intercomparison in the Permian Basin . If the dispersion modeling results indicated that a sensor would be exposed to a background-corrected methane concentration above one of these thresholds, for at least 1 min, the emission was assumed to be detected.…”

Section: Methodsmentioning

confidence: 99%

“…Evidence of intermittent large emission events and the limits of short-duration sampling has generated interest in the deployment of continuous emission monitoring systems on oil and gas production sites. In a typical deployment, three to four fixed ground sensors might be placed on a single site, with methane concentrations recorded continuously . Even a continuously operating network may not be able to detect all emissions, however.…”

Section: Introductionmentioning

confidence: 99%

“…In a typical deployment, three to four fixed ground sensors might be placed on a single site, with methane concentrations recorded continuously. 15 Even a continuously operating network may not be able to detect all emissions, however. Detection capabilities of continuous monitoring networks with fixed sensors depend on meteorological conditions, sensor detection limits, the number of sensors deployed, and sensor placement strategies.…”

Section: ■ Introductionmentioning

confidence: 99%

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Assessing Detection Efficiencies for Continuous Methane Emission Monitoring Systems at Oil and Gas Production Sites

Chen

¹

,

Schissel

²

,

Kimura

³

et al. 2023

Environ. Sci. Technol.

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Continuous monitoring systems, consisting of multiple fixed sensors, are increasingly being deployed at oil and gas production sites to detect methane emissions. While these monitoring systems operate continuously, their efficiency in detecting emissions will depend on meteorological conditions, sensor detection limits, the number of sensors deployed, and sensor placement strategies. This work demonstrates an approach to assess the effectiveness of continuous sensor networks in detecting infinite-duration and fixed-duration emission events. The case studies examine a single idealized source and a group of nine different sources at varying heights and locations on a single pad. Using site-specific meteorological data and dispersion modeling, the emission detection performance is characterized. For these case studies, infinite-duration emission events are detected within 1 h to multiple days, depending on the number of sensors deployed. The percentage of fixed-duration emission events that are detected ranged from less than 10% to more than 90%, depending on the number of sources, emission release height, emission event duration, and the number of sensors deployed. While these results are specific to these case studies, the analysis framework described in this work can be broadly applied in the evaluation of continuous emission monitoring network designs.

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“…The source was assumed to be emitting methane at a continuous rate of 10 kg/hr, to be consistent with the minimum detection threshold for advanced measurement technologies proposed by U.S. Environmental Protection Agency [20]. Three sensor detection thresholds were considered: 200ppb, 500ppb, and 1000ppb above background, representing detection ranges of field-deployed methane sensors [15]. If the dispersion modeling results indicated that a sensor would be exposed to a background-corrected methane concentration above one of these thresholds, for at least one minute, the emission was assumed to be detected.…”

Section: Defining Emission Detection and Emission Event Detectionmentioning

confidence: 99%

“…Evidence of intermittent large emission events, and the limits of short duration sampling, has generated interest in the deployment of continuous emission monitoring systems on oil and gas production sites. In a typical deployment, 3-4 fixed ground sensors might be placed on a single site, with methane concentrations recorded continuously [15]. Even a continuously operating network may not be able to detect all emissions, however.…”

Section: Introductionmentioning

confidence: 99%

Assessing detection efficiencies for continuous methane emission monitoring systems at oil and gas production sites

Chen

¹

,

Schissel

²

,

Kimura

³

et al. 2022

Preprint

Self Cite

0

View full text Add to dashboard Cite

Continuous monitoring systems, consisting of multiple fixed sensors, are increasingly being deployed at oil and gas production sites to detect methane emissions. While these monitoring systems operate continuously, their efficiency in detecting emissions will depend on meteorological conditions, sensor detection limits, the number of sensors deployed, and sensor placement strategies. This work demonstrates an approach to assess the effectiveness of continuous sensor networks in detecting infinite duration and fixed duration emission events from a point source, using a case study in west Texas. The case study examines a 10 kg/hr source at a height of 5.5m, representative of the emission pattern from a liquid storage tank. Using site specific meteorological data and dispersion modeling, emission detection performance was characterized. For this case study, infinite duration emission events were detected within 1 hour to multiple days, depending on the numbers of sensors deployed. The percentage of fixed duration emission events that were detected ranged from less than 30% to more than 90%, depending on the emission event duration and the number of sensors deployed. Because the dispersion modeling for the case study region predicted relatively narrow plumes, with steep concentration gradients, the benefit of using sensors with low detection thresholds was less important to system performance than the number of sensors deployed and the positioning of the sensors. While these results are specific to this case study, the analysis framework described in this work can be broadly applied in the evaluation of continuous emission monitoring network designs. Overall, while there can be time delays in continuous monitoring systems detecting continuous infinite duration emission events, and while some fixed duration emission events may not be detected, the detection efficiencies for continuous monitoring networks are greater than efficiencies for periodic short duration measurements, such as monthly or quarterly inspections.

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Automated Unmanned Systems Perform Safe Emissions Quantification & Reduction in Permian Operations

Churchill¹,

Wise²,

Cooper

³

et al. 2022

Day 3 Wed, October 05, 2022

2

0

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Traditional methods for monitoring emissions from production operations have typically employed optical gas imaging (OGI) cameras or Method 21 systems, based on an intermittent basis to determine and document methane gas leaks, which are then subsequently identified for repair (CFR, 2022). These OGI emissions monitoring surveys can have a subjective bias, are highly conditional on the skill of the camera operator, and are an inexact method of measuring quantity of the leak rate. With a renewed industry emphasis on methane emissions measurement and reduction, this paper describes a case study using a high-sensitivity sensor technology specifically targeting methane emissions, the unique capabilities engendered by its deployment on unmanned aerial systems (UAS), specifically leveraging automation in field-operation and data analysis, and its successful utilization in enabling emissions limitations over several production sites in the Permian. The use of automation enabled categorization of the leak type and intensity, and triage according to leak rate, facilitating prompt remedial action, directly limiting emissions. By automating the comprehensive flight paths, specific to equipment groups, e.g., compressors, tanks, flares etc., targeted repeat surveys confirmed that specific leaks were fixed, emphasizing a general downward trend in overall site- and asset-level emissions. Additionally, the use of high resolution UAS-generated orthomosaic maps enabled the direct placement of emissions data into the context of the actual operations at the time of the survey. also facilitating the generation of automated actionable reports, enabling repair teams to be directed, resulting in effective and necessary fixes. Furthermore, the campaign validated that following the set-up of the initial survey, subsequent regular, repeat surveys could be commissioned at the "push of a button", yielding reliable, actionable emissions data, with a direct impact on both environmental and financial impact.

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Field inter-comparison of low-cost sensors for monitoring methane emissions from oil and gas production operations

Cited by 4 publications

References 8 publications

Assessing Detection Efficiencies for Continuous Methane Emission Monitoring Systems at Oil and Gas Production Sites

Assessing Detection Efficiencies for Continuous Methane Emission Monitoring Systems at Oil and Gas Production Sites

Assessing detection efficiencies for continuous methane emission monitoring systems at oil and gas production sites

Automated Unmanned Systems Perform Safe Emissions Quantification & Reduction in Permian Operations

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