Leak Detection And Repair Research Articles

Large-Scale Controlled Experiment Demonstrates Effectiveness of Methane Leak Detection and Repair Programs at Oil and Gas Facilities.

Most jurisdictions around the globe use leak detection and repair (LDAR) programs to find and fix methane leaks from oil and gas operations. In this work, we empirically evaluate the efficacy of LDAR programs using a large-scale, bottom-up, randomized controlled field experiment across ∼200 oil and gas sites in Red Deer, Canada. We find that tanks are the single largest source of emissions, contributing to nearly 60% of the total emissions. The average number of leaks at treatment sites that underwent repair reduced by ∼50% compared to the control sites. Although control sites did not see a reduction in the number of leaks, emissions reduced by approximately 36%, suggesting potential impact of routine maintenance activities to find and fix large leaks. By tracking tags on leaking equipment over time, we find a high degree of persistence; leaks that are repaired remain fixed in follow-up surveys, while non-repaired leaks remain emitting at a similar rate, suggesting that any increase in observed leak emissions following LDAR surveys are likely from new leaks. Our results show that a focus on equipment and sites that are prone to high emissions, such as tanks and oil sites, is key to cost-effective mitigation.

The Role of Emission Size Distribution on the Efficacy of New Technologies to Reduce Methane Emissions from the Oil and Gas Sector.

Methane emissions from oil and gas operations exhibit skewed distributions. New technologies such as aerial-based leak detection surveys promise cost-effective detection of large emitters (greater than 10 kg/h). Recent policies such as the US Environmental Protection Agency (EPA) methane rule that allow the use of new technologies as part of leak detection and repair (LDAR) programs require a demonstration of equivalence with existing optical gas imaging (OGI) based LDAR programs. In this work, we illustrate the impact of emission size distribution on the equivalency condition between the OGI and site-wide survey technologies. Emission size distributions compiled from aerial measurements include significantly more emitters between 1 and 10 kg/h and lower average emission rates for large emitters compared to the emission distribution in the EPA rule. As a result, we find that equivalence may be achieved at lower site-wide survey frequencies when using technologies with detection thresholds below 10 kg/h, compared to the EPA rule. However, equivalence cannot be achieved with a detection threshold of 30 kg/h at any survey frequency, because most emitters across most US basins exhibit emission rates below 30 kg/h. We find that equivalence is a complex tradeoff among technology choice, design of LDAR programs, and survey frequency that can have more than one unique solution set.

A Practical Framework for Oil and Gas Operators to Estimate Methane Emission Duration Using Operational Data

Summary Methane management is a key greenhouse gas (GHG) reduction focus within the oil and gas industry. While there are a variety of techniques for methane detection and measurement, aircraft-mounted sensors have become popular for both academic studies and operators in onshore regions in North America due to their ability to screen many sites in a relatively short amount of time. Many traditional leak detection and repair (LDAR) techniques, like optical gas imaging (OGI), and emerging approaches, such as aircraft-based or satellite-based screenings, are periodic, which means that they can provide information about the presence of emissions and approximate rates during the observation period. Scaling periodic observations to annual emission estimates needed for regulatory and corporate reporting requires information on emission duration, which is not generally provided by the same screening techniques. In the literature to date, there have been several statistical approaches proposed for the annualization of basin-level methane observations, but these techniques may struggle to downscale to individual operators, across which methane emission intensities are expected to vary. In this paper, we propose a novel, conceptual framework for using other sources of data, such as records from operator inspections and parametric monitoring, to help define the duration of detected methane emissions. Such information may prove to be a useful input to measurement-informed methane emission protocols that are under development by multistakeholder groups, like GTI Energy Veritas and federal agencies in the United States.

A practical approach to LDAR effectiveness evaluation

As a growing number of oil and gas facilities worldwide implement leak detection and repair (LDAR) plans, the owners and the public are interested in better understanding their effectiveness, i.e. how total facility leak emission is decreased as a result of LDAR implementation. For this objective, it is critically important when calculating total mass leak emission to consider an estimated leak lifetime for the leakers found. Obviously, more frequent monitoring and shorter leak repair time should return lower leak lifetime and less emission. This simple yet important factor is mentioned but not detailed in existing guides. Some guides suggest formulae with the same equipment operating time both for leakers and non-leakers, which is not quite accurate since the actual leak lifetime could be significantly less than the total equipment operating time due to the proper LDAR implementation. In this article, we address this gap. The LDAR effectiveness evaluation approach utilizing leak lifetime is suggested and illustrated using examples.

Assessing the effectiveness and efficiency of methane regulations in British Columbia, Canada

ABSTRACT Many jurisdictions are introducing methane reduction policy as part of climate commitments, with a focus on the oil and gas supply chain. Periodic comprehensive leak detection and repair (LDAR) surveys or screening leak detection and repair surveys are required in the British Columbia, Canada oil and gas sector to reduce unintentional methane emissions caused by leaking infrastructure. By finding and fixing leaks quickly, emissions of methane, a potent greenhouse gas, are reduced. In this study, we explored how effectively British Columbia’s regulation, deposited in December 2018, made progress towards meeting the policy objective of a 45% decrease in methane emissions by 2025 from a 2014 baseline. We evaluated the performance and cost effectiveness of regulatory-prescribed LDAR programmes using data collected by the BC Energy Regulator (formerly BC Oil and Gas Commission) for the 2020 year, and survey cost data submitted by service providers. We found that the new regulation was only partially effective due to low compliance rates. We also observed heavy tail leak distributions in LDAR data collected by service companies, but comparatively narrow leak distributions in data from permit holders who internalized LDAR operations, suggesting a difference in work practice or the use of equipment. Comprehensive leak detection surveys were found to be more cost efficient ($23 CAD/tCO2e reduced) compared to screening surveys ($1,787 CAD/tCO2e reduced) because more methane leaks are detected in comprehensive assessments. To meet methane reduction targets, we recommend that: 1) jurisdictions work to improve compliance rates by introducing minimum administrative penalties specific to noncompliance; 2) that all future LDAR surveys are instrument-based; 3) limiting turnaround time limits so that repairs are not delayed indefinitely; and 4) that LDAR completed internally by permit holders undergo independent third-party verification.

Source profile study of VOCs unorganized emissions from typical aromatic devices in petrochemical industry

Volatile organic compounds (VOCs) are significant pollutants generated during the processes of petroleum refining and chemical production. Aromatic hydrocarbons, in particular, pose a great risk to human health. Nevertheless, unorganized emissions of VOCs from typical aromatics units remain poorly studied and reported. Therefore, it is vital to achieve precise control over aromatic hydrocarbons while managing VOCs. In this study, two typical aromatics production devices in petrochemical enterprises, namely aromatics extraction devices and ethylbenzene devices, were selected. The fugitive emissions of VOCs from the process pipelines in the units were investigated. Samples were collected and transferred using the EPA bag sampling method and HJ 644 and analyzed using gas chromatography–mass spectrometry. The results indicated that a total of 112 VOCs were emitted during the six rounds of sampling in the two types of devices, with alkanes (61 %), aromatic hydrocarbons (24 %), and olefins (8 %) being the primary types of VOCs emitted. The results also revealed the unorganized emissions characteristic substances of VOCs in the two types of devices, with slight differences in the types of VOCs emitted. The study found significant differences in the detection concentrations of aromatic hydrocarbons and olefins, as well as the types of detected chlorinated organic compounds (CVOCs), between the two sets of aromatics extraction units in distinct regions. These differences were closely related to the processes and leakages in the devices and can be effectively controlled by enhancing leak detection and repair (LDAR) and other measures. This article offers guidance for compiling VOCs emission inventories and improving the management of VOCs emissions in petrochemical enterprises by refining the source spectrum at the device scale. The findings are significant for analyzing VOCs unorganized emission factors and promoting safe production in enterprises.

Analysis of a tiered top-down approach using satellite and aircraft platforms to monitor oil and gas facilities in the Permian basin

As energy systems transition towards decarbonization, natural gas is expected to play an important role as a cleaner hydrocarbon fuel source to bridge the gap between renewable energy production and increasing energy demand. Regulations aim to reduce methane emissions from natural gas systems to ensure the total environmental impacts of natural gas production and consumption are indeed lesser than for other fossil fuels. GHGSat Inc., has developed a tiered top-down remote sensing approach utilizing satellite and airborne instruments to monitor methane emissions from industrial sites globally. This satellite-aircraft hybrid system was demonstrated in the Permian basin for detecting and quantifying methane emissions from oil and gas (O&G) facilities. A heavy-tail distribution of methane emissions was observed, with 12% of emitting targets (total sample size of 106) accounting for over 50% of total detected methane emissions. Traditional leak detection and repair (LDAR) programs often incorporate multiple annual screening campaigns with ground-based optical gas imaging (OGI) technologies to detect methane leaks from O&G infrastructure. Three alternative LDAR programs incorporating GHGSat's satellite and airborne monitoring technologies were modelled using the Arolytics AroFEMP methane model. Model parameters were derived from GHGSat's 2021 Permian basin data to evaluate their equivalency and costs against traditional LDAR monitoring. When compared to the required practice of performing OGI surveys four times per year, the proposed alternative LDAR programs were modelled to have at least equivalent methane reduction performance while being substantially more cost-effective.

Origins of Oil and Gas Sector Methane Emissions: On-Site Investigations of Aerial Measured Sources.

Success in reducing oil and gas sector methane emissions is contingent on understanding the sources driving emissions, associated options for mitigation, and the effectiveness of regulations in achieving intended outcomes. This study combines high-resolution, high-sensitivity aerial survey data with subsequent on-site investigations of detected sources to examine these points. Measurements were performed in British Columbia, Canada, an active oil- and gas-producing province with modern methane regulations featuring mandatory three times per year leak detection and repair (LDAR) surveys at most facilities. Derived emission factors enabled by source attribution show that significant methane emissions persist under this regulatory framework, dominated by (i) combustion slip (compressor exhaust and also catalytic heaters, which are not covered in current regulations), (ii) intentional venting (uncontrolled tanks, vent stacks or intentionally unlit flares, and uncontrolled compressors), and (iii) unintentional venting (controlled tanks, unintentionally unlit/blown out flares, and abnormally operating pneumatics). Although the detailed analysis shows mitigation options exist for all sources, the importance of combustion slip and the persistently large methane contributions from controlled tanks and unlit flares demonstrate the limits of current LDAR programs and the critical need for additional monitoring and verification if regulations are to have the intended impacts, and reduction targets of 75% and greater are to be met.

Technological avenues and market mechanisms to accelerate methane and nitrous oxide emissions reductions.

Strategies targeting methane (CH4) and nitrous oxide (N2O) emissions are critical to meeting global climate targets. Existing literature estimates the emissions of these gases from specific sectors, but this knowledge must be synthesized to prioritize and incentivize CH4 and N2O mitigation. Accordingly, we review emissions sources and mitigation strategies in all key sectors (fuel extraction and combustion, landfilling, agriculture, wastewater treatment, and chemical industry) and the role of carbon markets in reducing emissions. The most accessible reduction opportunities are in the hydrocarbon extraction and waste sectors, where half (>3 Gt-CO2e/year) of the emissions in these sectors could be mitigated at no net cost. In total, 60% of CH4 emissions can be mitigated at less than $50/t-CO2. Expanding the scope of carbon markets to include these emissions could provide cost-effective decarbonization through 2050. We provide recommendations for carbon markets to improve emissions reductions and set prices to appropriately incentivize mitigation.

Reduction of fugitive VOC emissions using leak detection and repair (LDAR) in a petroleum refinery of Pearl River Delta, China

Fugitive volatile organic compound (VOC) emissions from the petroleum-refining industry constitute a complex issue in China. This problem has a wide range of implications that require comprehensive measures, including a series of critical policing and legal injunctions in response to regional atmospheric pollution and the resulting safety hazards. In particular, process-based leak detection and repair (LDAR) surveys commonly used in developed countries should be vigorously promoted for fugitive VOC emission reduction. In this study, a campaign was conducted to measure the effectiveness of LDAR surveys by quantifying fugitive VOC emissions caused by equipment leaks in a local petroleum refinery in the Pearl River Delta (PRD) region of China. The leakage points detected in the initial survey accounted for 0.63 % of all the components within the refinery, among which open-ended pipes and valve packing had the highest ratio. After the procedure, the leakage rate was reduced to 0.23 %, suggesting a satisfactory repair performance. The process-based fugitive emission characteristics of each refining unit, storage tank, and loading area were investigated, and the corresponding composite profiles were estimated using the correlation equation method and data from the LDAR survey. Results demonstrated that the total emission of the refinery was 12,595.83 kg/a, with dominant VOC species of alkanes being emitted in nearly all units. Finally, the secondary organic aerosol formation potential (SOAP) and ozone formation potential (OFP) were estimated. All the above results were process-oriented and demonstrated that establishing a local LDAR system that considers the differences in VOC emissions from various manufacturing facilities should be the key strategy for future VOC emission reduction from the entire petroleum refining industry in China.

Leak detection and repair data from California's oil and gas methane regulation show decrease in leaks over two years

Leak detection and repair (LDAR) programs are commonly used to identify and mitigate unintentional emissions at oil and gas facilities. This study utilizes regulatory reporting data from 2018 to 2019 at over 300 facilities (including crude oil production, natural gas production, natural gas storage, and natural gas transmission) to evaluate the effectiveness of California's statewide LDAR requirements. The results from this study can offer guidance for other jurisdictions looking to reduce methane emissions from oil and gas facilities. Total leaks found in 2018 and 2019 were 11,359 and 7,208, respectively. Although the number of components surveyed increased from 2018 to 2019 by 16%, the number of leaks decreased over the eight quarterly surveys (slope [95% confidence interval]: -287 leaks/quarter [-395, -180]). In both 2018 and 2019, 20% of all leaks accounted for approximately 50% of estimated emissions from leaking components, demonstrating the importance of frequent LDAR surveys to mitigate emissions from larger leaks. Emission reductions from LDAR surveys were estimated by using correlation equations to roughly approximate emission rates based on measurements of concentration. In 2018 and 2019, emission reductions were 5,400 and 3,000 metric tons methane, respectively (∼9% and ∼4% of total fugitive methane emissions from oil and gas production and processing according to California's emissions inventory for 2018 and 2019).

A review of whole-process control of industrial volatile organic compounds in China

Volatile organic compounds (VOCs) play an important role in the formation of ground-level ozone and secondary organic aerosol (SOA), and they have been key issues in current air pollution prevention and control in China. Considerable attention has been paid to industrial activities due to their large and relatively complex VOCs emissions. The present research aims to provide a comprehensive review on whole-process control of industrial VOCs, which mainly includes source reduction, collection enhancement and end-pipe treatments. Lower VOCs materials including water-borne ones are the keys to source substitution in industries related to coating and solvent usage, leak detection and repair (LDAR) should be regarded as an efficient means of source reduction in refining, petrochemical and other chemical industries. Several types of VOCs collection methods such as gas-collecting hoods, airtight partitions and others are discussed, and airtight collection at negative pressure yields the best collection efficiency. Current end-pipe treatments like UV oxidation, low-temperature plasma, activated carbon adsorption, combustion, biodegradation, and adsorption-combustion are discussed in detail. Finally, several recommendations are made for future advanced treatment and policy development in industrial VOCs emission control.

New Technologies Can Cost Effectively Reduce Oil and Gas Methane Emissions, but Policies Will Require Careful Design to Establish Mitigation Equivalence.

Reducing methane emissions from oil and gas systems is a central component of US and international climate policy. Leak detection and repair (LDAR) programs using optical gas imaging (OGI)-based surveys are routinely used to mitigate fugitive emissions or leaks. Recently, new technologies and platforms such as planes, drones, and satellites promise more cost-effective mitigation than existing approaches. To be approved for use in LDAR programs, new technologies must demonstrate emissions mitigation equivalent to existing approaches. In this work, we use the FEAST modeling tool to (a) identify cost vs mitigation trade-offs that arise from using new technologies and (b) provide a framework for effective design of alternative LDAR programs. We identify several critical insights. First, LDAR programs can trade sensitivity for speed without sacrificing mitigation outcomes. Second, low sensitivity or high detection threshold technologies have an effective upper bound on achievable mitigation that is independent of the survey frequency. Third, the cost effectiveness of tiered LDAR programs using site-level detection technologies depends on their ability to distinguish leaks from routine venting. Finally, "technology equivalence" based on mitigation outcomes differs across basins and should be evaluated independently. The FEAST model will enable operators and regulators to systematically evaluate new technologies in next-generation LDAR programs.

Characteristics of Volatile Organic Compound Leaks from Equipment Components: A Study of the Pharmaceutical Industry in China

Leak detection and repair (LDAR) plays an important role in controlling the fugitive emission of volatile organic compound (VOC) from chemical enterprises. At present, many policies and standards issued in China have set clear requirements for implementing LDAR in the pharmaceutical industry. In this study, the LDAR work of nine typical pharmaceutical enterprises was selected for analysis to allow investigation of the characteristics of VOC emissions from leaking equipment components. Some suggestions for controlling VOC are proposed to provide a reference for managing the fugitive emissions of VOC from pharmaceutical enterprises. The results showed that the number of equipment components used by the pharmaceutical enterprises ranged from several thousand to more than 20,000, which is lower than that in oil refining and coal chemical enterprises. The predominant leaky component was the flange, which accounted for 56.31% of the total, followed by connectors (21.51%) and valves (18.53%). Light liquid medium components accounted for the largest proportion of equipment (52.83%) on average, followed by gas medium components (45.52%, on average). Heavy liquid medium components, which are rarely used in pharmaceuticals, accounted for only 1.65%. The average leak ratio of the components in the pharmaceutical industry was approximately 0.99%. The leak ratio of the open-ended line was much higher than that of other types of components, reaching an average of 5.00%, while that value was only 0.92% for the flange, despite the numbers and proportion of them that were in use. The total annual VOC leakage from the nine pharmaceutical enterprises studied in this work was 20.11 tons, with an average of 2.23 tons per enterprise and an average of 0.22 kg/a per equipment component. Flanges, connectors, and valves were the top three contributors to leakage, generating 39.17%, 38.72%, and 16.79% of the total, respectively, and a total proportion of 94.68%. Although the number of pumps accounted for only 0.15% of the components, it generated 1.94% of the leakage. In terms of different production processes, the greatest unit product leakage came from the bulk production of chemicals used for pharmaceuticals, reaching 0.085 t/a. The production from traditional Chinese medicine enterprises was the lowest (0.011 t/a), which was only 12.80% of the leakage from the bulk production of chemicals for drugs. The leakage of VOC from the equipment components in the nine enterprises was reduced, to varying degrees, using LDAR. The overall reduction ratio was between 23.55% and 67.72%, with an average of 44.02%. The reduction in leakage was relatively significant after the implementation of LDAR; however, there is still room for improvement. Pharmaceutical enterprises should improve their implementation of LDAR and reduce VOC leakage by reducing the number of inaccessible components used and increasing the repair ratio of leaky components. Controlling the source of component leakage, which should be emphasized, can be realized by cutting down the number of components used, adopting low-leakage equipment, and putting anti-leakage measures in place.

Can new mobile technologies enable fugitive methane reductions from the oil and gas industry?

New mobile platforms such as vehicles, drones, aircraft, and satellites have emerged to help identify and reduce fugitive methane emissions from the oil and gas sector. When deployed as part of leak detection and repair (LDAR) programs, most of these technologies use multi-visit LDAR (MVL), which consists of four steps: (a) rapidly screen all facilities, (b) triage by emission rate, (c) follow-up with close-range methods at the highest-emitting sites, and (d) conduct repairs. The proposed value of MVL is to identify large leaks soon after they arise. Whether MVL offers an improvement over traditional single-visit LDAR (SVL), which relies on undirected close-range surveys, remains poorly understood. We use the Leak Detection and Repair Simulator (LDAR-Sim) to examine the performance and cost-effectiveness of MVL relative to SVL. Results suggest that facility-scale MVL programs can achieve fugitive emission reductions equivalent to SVL, but that improved cost-effectiveness is not guaranteed. Under a best-case scenario, we find that screening must cost < USD 100 per site for MVL to achieve 30% cost reductions relative to SVL. In scenarios with non-target vented emissions and screening quantification uncertainty, triaging errors force excessive close-range follow-up to achieve emissions reduction equivalence. The viability of MVL as a cost-effective alternative to SVL for reducing fugitive methane emissions hinges on accurate triaging after the screening phase.

Methods of detecting and measuring fugitive methane emissions from elements of the gas transmission infrastructure – the results of GERG project Detection and Measurement of Fugitive Emissions of Natural Gas from the Transmission Systems

The article presents the results of the project carried out by GAZ-SYSTEM in cooperation with 5 other European gas Transmission System Operators (TSO) – ENAGAS, Fluxys, Gasunie, Snam and GRTgaz. The objective of the project was to investigate and identify the most useful devices for detecting and measuring methane emissions from infrastructure components typical for the TSO. The market analysis showed that methane detectors utilizing different principles of operation are available, but there are much fewer devices for measuring emission rates. 5 devices were selected for tests: 3 exclusively for detection based on the D-1 (semiconductor sensor), D-2 (infrared optical gas detection system), D-3(laser technology) principle of operation, and 2 devices that also enable emissions measurement – P-1 (ultrasound imaging) and P-2 (quantitative optical gas imaging). Laboratory tests were carried out in March 2020 at the Enagás’ Metrological &amp; Innovation Center (M&amp;I); according to the approved program, methane leaks were generated from deliberately unsealed valves, flanges, threaded and open-ended pipe connections. Field tests were carried out at the measuring gas station near the M&amp;I. The main purpose of the research was to verify the accuracy of the selected measuring instruments. It was carried out at different flowrate and various methane concentrations in the gas escaping from the components. Ease of use of the devices, their speed and range of operation were assessed. The results showed both the advantages and limitations of each device, and they clearly indicated that the assessment of methane emissions from gas transmission infrastructure components requires the use of at least two different devices. The results indicate that sniffer devices, characterized by the fact that the probe must be placed in the vicinity of the source of emission, give results similar to the FID Detector, most commonly used in Leak Detection and Repair (LDAR) programs, but can be used in a wider range of methane concentrations. D-3 has a fast response time and a wide measuring range, but their unit of measurement i.e. ppm-m prevents the conversion of the results into methane concentration without additional measurements of the distance between the leak and the device. The P-1 and P-2 allow to measure the emissions in real time, while the measurement errors for both devices are comparable, ranging from about 70% to 100%.

Mobile sampling of methane emissions from natural gas well pads in California

The oil and natural gas sector is the second largest source of methane (CH4) emissions in the U.S. (28% in 2018), and several studies have suggested that real-world emissions from this sector may be higher than previously reported estimates. This study was designed to measure methane emissions from non-associated (i.e., produced without crude oil extraction) natural gas (NG) well pads in California, by applying a novel mobile measurement system combined with a source characterization model. This study surveyed 86 non-associated NG well pads (66 active and 20 idle well pads) in northern California during a two-week field campaign in 2018. The mean emission rate from active non-associated NG well pads was estimated to be 9.5 (95% CI: 6.1–14.6) kg CH4/d. By extrapolating the survey results to the entire state, the annual methane emissions from all active non-associated NG well pads were 3.2 (95% CI: 2.0–5.1) Gg CH4/y, which represents roughly 5% of CH4 emissions from the oil and natural gas production sector in California. The methane emission rates exhibited a fat-tail distribution, with roughly 15% of the active well pads responsible for >85% of the total measured emissions. This result suggests that controlling a small number of large emitters can significantly reduce methane emissions from this sub-sector. Methane emissions were also detected from over 60% of the idle well pads, with a similar fat-tail distribution but much smaller magnitudes than the active well pads. Quick screening tools to identify and fix these unexpected fugitive leaks can offer useful real-world emission reductions. The mobile measurement system was also able to detect emissions from more well pads when compared to the use of an optical gas imaging camera, which suggests that mobile measurement techniques can be an effective screening tool to support leak detection and repair (LDAR) programs.

The application of leak detection and repair program in VOCs control in China’s petroleum refineries

ABSTRACT Volatile organic compounds (VOCs) contribute to the formation of ground-level ozone. This causes the phenomena of haze and photochemical smog pollution. Recently, the leak detection and repair (LDAR) program was required to implement in China’s petroleum industry on the background of the huge emissions from equipment leaks. This paper analyzed and compared the application of LDAR program in four petroleum refineries and six typical processing units in these refineries. The results showed that non-flanged connectors, flanges, valves, and open-ended lines were the most common components, which accounted for over 99% in these refineries. And over half were non-flanged connectors. About 0.2% to 0.4% of all components were found to leak and emitted up to 91.8% of VOCs, especially the leaking valves and open-ended lines. And over 88.5% of VOC emissions were from high leaking components. The VOC emissions reduced 42% to 57% by repairing 42% to 81% of leaking components. And 90% of the reduction was achieved by repairing high leaking components. Besides, under the same processing capacity, the gas fractionation unit and continuous catalytic reforming unit have a higher average number of components, leaking components and VOC emissions than the other four units. Finally, this paper proposed some problems and suggestions during the implementation of LDAR program. These findings can enhance and improve the effectiveness of LDAR program, and establish a comprehensive VOCs control system, which provides a scientific basis and technical support for the government and refineries. Implications: Recently, China required industries to implement leak detection and repair (LDAR) program to control volatile organic compound (VOC) emissions, especially the petroleum industry. In this paper, we analyzed and compared the LDAR program implementation in four refineries and six typical processing units in these refineries. The results indicate that the implementation of LDAR program was highly effective in petroleum industry. The comparison helps us to enhance the effectiveness of LDAR program by locating the high VOC emission components and units, which provides technical support for the government and refineries in developing specific regulations and plans.

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

Reducing methane emissions from the oil and gas industry is a critical climate action policy tool in Canada and the US. Optical gas imaging-based leak detection and repair (LDAR) surveys are commonly used to address fugitive methane emissions or leaks. Despite widespread use, there is little empirical measurement of the effectiveness of LDAR programs at reducing long-term leakage, especially over the scale of months to years. In this study, we measure the effectiveness of LDAR surveys by quantifying emissions at 36 unconventional liquids-rich natural gas facilities in Alberta, Canada. A representative subset of these 36 facilities were visited twice by the same detection team: an initial survey and a post-repair re-survey occurring ∼0.5–2 years after the initial survey. Overall, total emissions reduced by 44% after one LDAR survey, combining a reduction in fugitive emissions of 22% and vented emissions by 47%. Furthermore, >90% of the leaks found in the initial survey were not emitting in the re-survey, suggesting high repair effectiveness. However, fugitive emissions reduced by only 22% because of new leaks that occurred between the surveys. This indicates a need for frequent, effective, and low-cost LDAR surveys to target new leaks. The large reduction in vent emissions is associated with potentially stochastic changes to tank-related emissions, which contributed ∼45% of all emissions. Our data suggest a key role for tank-specific abatement strategies as an effective way to reduce oil and gas methane emissions. Finally, mitigation policies will also benefit from more definitive classification of leaks and vents.

A Common Risk Classification Concept for Safety Related Gas Leaks and Fugitive Emissions?

Gas leaks in the oil and gas industry represent a safety risk as they, if ignited, may result in severe fires and/or explosions. Unignited, they have environmental impacts. This is particularly the case for methane leaks due to a significant Global Warming Potential (GWP). Since gas leak rates may span several orders of magnitude, that is, from leaks associated with potential major accidents to fugitive emissions on the order of 10−6 kg/s, it has been difficult to organize the leaks in an all-inclusive leak categorization model. The motivation for the present study was to develop a simple logarithmic table based on an existing consequence matrix for safety related incidents extended to include non-safety related fugitive emissions. An evaluation sheet was also developed as a guide for immediate risk evaluations when new leaks are identified. The leak rate table and evaluation guide were tested in the field at five land-based oil and gas facilities during Optical Gas Inspection (OGI) campaigns. It is demonstrated how the suggested concept can be used for presenting and analysing detected leaks to assist in Leak Detection and Repair (LDAR) programs. The novel categorization table was proven valuable in prioritizing repair of “super-emitter” components rather than the numerous minor fugitive emissions detected by OGI cameras, which contribute little to the accumulated emissions. The study was limited to five land based oil and gas facilities in Norway. However, as the results regarding leak rate distribution and “super-emitter” contributions mirror studies from other regions, the methodology should be generally applicable. To emphasize environmental impact, it is suggested to include leaking gas GWP in future research on the categorization model, that is, not base prioritization solely on leak rates. Research on OGI campaign frequency is recommended since frequent coarse campaigns may give an improved cost benefit ratio.