Posts Tagged ‘venting’

According to EIA data for 2001-2021, Gulf of Mexico flaring and venting volumes peaked in 2001 at 21.6 bcf, 2.25 times the volume flared or vented in 2022 (ONRR data for 2022). However, gas production in 2001 was 5.05 tcf, 6.4 times higher than in 2022. The % of the produced gas that was flared or vented in 2001 was thus 0.4%, less than 1/3 the 2022 rate of 1.22%.

Points to consider:

left axis: gas produced in millions of cubic feet; right axis: % flared or vented

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From ONRR OGOR B data:

OWG flared59196987
OWG vented14051638
GWG flared311213
GWG vented548722
total flared and vented81839559
total gas prodution791,983784,238
% flared or vented1.031.22
OWG=oil well gas; GWG=gas well gas; all volumes are in MMCF


  • Of the 784 bcf produced, 9.6 bcf (1.2%) were either vented or flared (vs. 1.03% in 2021). With the exception of 2020 (1.3%), this is the highest % of gas flared/vented from 2015-2022.
  • The % of gas produced that is flared or vented is trending upward (first chart below).
  • Both the gas flaring and venting volumes were higher in 2022 (vs. 2021) despite lower gas production.
  • Assuming oil-well gas (OWG) production of 600 bcf (final 2022 volume not yet available), approximately 1.4% (8.6/600) of the OWG was flared or vented.
  • 2022 OWG flaring volume increased by 18% vs. 2022 despite nearly identical total oil production
  • A very large increase in OWG flaring in December skewed the 2022 data (921 million cu ft vs 522 million in November, see 2nd chart below). OWG vented and gas-well gas (GWG) vented also spiked in December (third chart). Were these spikes associated with production startups, major compressor issues, administrative/accounting corrections, or other issues?
  • Although total venting increased by 407 million cu ft (21%) in 2023 vs. 2022, the overall venting trend is still favorable (last chart).
  • The previously noted inconsistencies in flaring data sets remain a concern.
  • Kudos to ONRR for posting the flaring/venting data.
  • More regulator/industry transparency on flaring episodes is needed, particularly in light of the PNAS paper and the June 2022 Inspector General Report.


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An interesting study published in the Proceedings of the National Academy of Sciences (PNAS) was brought to my attention by leading offshore energy historian Tyler Priest. The study used airborne observations and emissions reports to measure the carbon intensity (CI) of Gulf of Mexico oil and gas production. Their CI measure is grams of CO2 equivalent of greenhouse gas emissions per megajoule of energy produced.

The authors conclude that inventory emissions of CO2 (as reported to BOEM) “are generally consistent with observations from our aircraft survey, suggesting that combustion is well represented in the federal inventory.

However, that is not the case for methane (CH4) emissions which are underestimated by the Federal inventories. As summarized in the chart below, deepwater facility methane emissions are consistent with the reported inventories, but shelf emissions in State and Federal waters differ significantly.


  • As previously discussed, the lower CI for deepwater production is entirely consistent with expectations. When the most modern 5% (57) of GoM platforms are producing 93% of the oil and 76% of the gas, their CI should be impressive (which indeed it is).
  • As summarized using ONRR data, more gas-well gas was vented from 2015-2021 than was flared, which is not what you want from a GHG standpoint. Gas wells are predominantly at shallow water facilities, many of which are not equipped with flare booms.
  • Oil-well gas, most of which is produced at deepwater platforms, is flared rather than vented by a ratio of approximately 4 to 1.
  • About 15 years ago, the Federal government (MMS) considered requiring that older production platforms be retrofitted with flare booms, but safety, space limitations, and cost considerations precluded such a regulation. Instead, additional flaring/venting limits, and measurement and reporting requirements were imposed.
  • One bad actor may have been a major contributor to the shelf methane emissions observed during the study’s observational flights. That company entered into bankruptcy proceedings. Presumably those issues have been resolved and more rigorous monitoring and enforcement practices have been implemented. I’ll be looking at the 2022 ONRR flaring and venting data for evidence of such improvement. The remainder of the 2022 data should be available in May.
  • The subject study’s only observational measurements were in August 2020. Followup airborne measurements would be helpful.
  • The study only considered production emissions. Shelf facilities are primarily natural gas producers and would thus have a lower relative CI when consumed.
  • When will updated BOEM GOADS flaring and venting data be available? The latest data are for 2017 (cover below)? Are GOADS data being compared with ONRR and World Bank data?

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Gulf of Mexico flaring and venting data have been sorted for the years 2015-2021. The reporting of these data is mandatory and strictly enforced, so these ONRR numbers should be accurate.

Biggest surprise: The biggest surprise is that there were no big surprises in the data. The % of gas flared and vented were generally consistent with expectations based on familiarity with historical data.

Biggest disappointment: the continued sharp decline in nonassociated (gas-well) gas production. GoM gas well gas production exceeded 4 tcf annually in the 1990s and was still above one tcf ten years ago. Since then, GWG production has declined by 80%. Nonassociated offshore natural gas has important environmental advantages, so the decline in production should be a major concern to policy makers

Encouraging sign: The % of oil-well gas vented has ticked down over the past 2 years which is encouraging from a GHG standpoint. This is presumably because most associated gas is produced on modern deepwater facilities equipped with flare booms. An astute politician would be rushing to take credit for this achievement.😀

Unfavorable ratio: Although the volumes are low (<1 Bcf combined in 2021), more gas-well gas was vented each year than flared. This is presumably because older shelf facilities without flare booms still produce much of the natural gas.


  • ONRR: Office of Natural Resources Revenue
  • GoM: Federal waters of the Gulf of Mexico
  • OWGP: oil-well gas production
  • GWGP: gas-well gas production
  • OWGF: oil-well gas flared
  • OWGV: oil-well gas vented
  • GWGF: gas-well gas flared
  • GWGV: gas-well gas vented

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Kudos to ONRR for posting complete flaring and venting data for all oil and gas operations on US Federal and Indian lands. These data, which distinguish between oil-well gas and gas-well gas, are included in the large “Production Disposition by Month” file that can be downloaded here.

The data should give us a good read on flaring and venting trends and help resolve the inconsistencies previously identified.

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Given the importance of flaring and venting from both environmental and resource conservation standpoints, accurate and reliable data are necessary and should be readily available to the public. ONRR has advised me that they will begin posting flaring and venting data on their website within 2 months. This is a positive step. Currently, data from the 3 primary sources differ considerably.

Data Sources:


  • The EIA (from BSEE) and ONRR flaring/venting numbers should be the same given that the ONRR data are reported in accordance with BSEE regulations, and BSEE is presumably providing ONRR data to EIA. This needs to be clarified.
  • The World Bank’s gas flaring estimates are based on observations from satellites. This explains their lower numbers given that vented gas would not be detected and some flares might be missed.
  • In a 1/2021 interview with World Oil, the exiting BSEE Director commented that the “industry has consistently achieved a ratio of less than 1.25% of flared, vented gas to produced gas.” However, based on EIA flaring and venting data (from BSEE per EIA) and EIA gas production data, the volume of gas flared/vented exceeded 1.25% of the gas produced from 2016-2020 and was as high as 1.8% in 2019. (See the chart below.) Even if the lower ONRR flaring/venting totals are used, those volumes exceeded 1.25% in 2019 (1.5%).
  • BSEE/ONRR should make more detailed flaring/venting data available so that the differences between facilities and sectors (e.g. deepwater vs. shelf) could be assessed. Efforts should also be made to post these data in a more timely manner. At this time, 2021 data are still not available.

Reports of interest:

  • Argonne report for BSEE (2017):
    • p. 17 – “The 2015 BSEE/BOEM study on reducing methane emissions observed that “while natural gas production has declined, …vented and flared gas volumes as a percentage of produced natural gas are increasing” and noted that additional investigation is needed to determine why.” This is consistent with my observations and is probably due in large part to the fact that most gas production is now from oil-wells (e.g. associated gas).
    • p. 24 – “Argonne estimates, in 2015, platform startups for deep-water floating structures accounted for roughly 15% of the total annual flaring volume on the OCS and an additional 20% of the annual total resulted from monthly spikes associated with compressor outage, pipeline maintenance, and well-unloading.”
  • Univ. of Michigan study (2020): “Large, older facilities situated in shallow waters tended to produce episodic, disproportionally high spikes of methane emissions. These facilities, which have more than seven platforms apiece, contribute to nearly 40% of emissions, yet consist of less than 1% of total platforms.” 

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Among other provisions, EPA’s proposed rule, issued on 11/2/2021, specifies that associated gas be handled as follows:

Route associated gas to a sales line. If access to a sales line is not available, the gas can be used as an onsite fuel source, used for another useful purpose that a purchased fuel or raw material would serve, or routed to a flare or other control device that achieves at least 95 percent reduction in methane and VOC emissions.

Because the Dept. of the Interior has jurisdiction over air emissions on most of the Gulf of Mexico OCS, I assume this proposed rule does not apply to those facilities. However, the EPA proposal is not entirely clear in that regard. If the EPA proposal does not apply, will BOEM/BSEE be proposing similar restrictions in their regulations?

MMS/DOI considered prohibiting venting, but determined that adding flaring capability was not feasible for many shelf platforms, and for some platforms there would have been a net increase in emissions. That said, venting is not insignificant. A 2017 Argonne study indicated (table 2) that, for shelf platforms from 2011 through 2015, more than 3 times as much gas was vented as was flared. More recent data should be reviewed to get a better sense of the costs, benefits, and safety considerations associated with achieving further reductions in venting.

Current flaring/venting regulations for OCS facilities are here.

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