M ETHANE E MISSIONS E STIMATES FROM O IL AND N ATURAL G AS P RODUCTION U SING A TMOSPHERIC M EASUREMENTS Anna Karion, Colm Sweeney, Eric Kort, Paul Shepson, Mackenzie Smith, M. Obie Cambaliza, Tegan Lavoie, Sonja Wolter, Stephen Conley, Gabrielle Pétron, Tim Newberger, Scott Herndon, Tara Yacovitch, Chris Rella, Mike Hardesty, Alan Brewer, Jon Kofler Photo: sunset over the Denton airport, by Sonja Wolter
Why (continue to) study US oil and gas CH 4 emissions? Methane (CH 4 ) is the principal component of natural gas and a powerful greenhouse gas (GWP 100 yrs = 28) Methane is released in fugitive emissions from oil and natural gas production, processing, etc. Emissions of methane from natural and anthropogenic sources are not well quantified (globally or regionally). Recent studies and overviews (Brandt et al., Science , 2014) show high emissions but they generally cover only a small fraction of US production. 2 NOAA Global Monitoring Division Annual Conference, May 21 2014
So what are the CH 4 emissions from natural gas? EPA Inventory of GHG Sources and Sinks 15 12 2010 Tg CH4/yr 10 Tg CH4/yr Report 10 8 Distribution 2011 6 Report Transmission 4 5 2013 Processing 2 Report Production 0 0 2010 2011 2013 2004 2009 1 2 3 Report Year 3 Leakage % CH4 Distribution 2 Transmission 1 Processing 0 Production 2010 2011 2013 1 2 3 Report 3 NOAA Global Monitoring Division Annual Conference, May 21 2014
Mass Balance Approach for Emissions Estimation Wind Wind Downwind CH 4 Background CH 4 mixing height (PBL) emissions Molar CH 4 enhancement in PBL CH 4 flux + z b PBL ∫ ∫ = cos θ ∆ n V X n dz dx CH CH air 4 4 − b z gnd Perpendicular wind speed 4 NOAA Global Monitoring Division Annual Conference, May 21 2014
TEXas Methane EXperiment Barnett Shale: 7% of US gas production; one of top 3 shale plays in US 6 NOAA Global Monitoring Division Annual Conference, May 21 2014
Texas Methane Experiment Phase I: March 2013 University of Colorado NOAA/ESRL (GMD, CSD) Picarro Shell / Sanders Geophysics Aerodyne Penn State (Davis group) Phase II: October 2013 Purdue (Shepson group) University of Michigan (Kort) University of Cincinnati (Townsend-Small) UC Irvine (Blake group) University of Houston West Virginia University Duke Princeton & UT Dallas LI-COR 7 NOAA Global Monitoring Division Annual Conference, May 21 2014
Texas Methane Experiment: Aircraft Scientific Aviation Mooney Purdue Duchess 8 NOAA Global Monitoring Division Annual Conference, May 21 2014
19 Oct 2013 Upwind (Duchess) wind Downwind (Mooney) 10 NOAA Global Monitoring Division Annual Conference, May 21 2014
19 Oct 2013 5 downwind transects CH 4 C 2 H 6 Methane (left) and ethane (right) in five separate downwind transects show consistency of plume. They also indicate that a portion of the methane enhancement does not correspond with an ethane enhancement. 12 NOAA Global Monitoring Division Annual Conference, May 21 2014
13 NOAA Global Monitoring Division Annual Conference, May 21 2014
Total CH 4 Emission Mean of nine flights 14 NOAA Global Monitoring Division Annual Conference, May 21 2014
10172014 Attribution to oil and gas Oil producing wells Dry gas producing wells 17 NOAA Global Monitoring Division Annual Conference, May 21 2014
Ethane to Methane Ratio: 19 Oct 2013 18 NOAA Global Monitoring Division Annual Conference, May 21 2014
Ethane to Methane Ratio: 19 Oct 2013 ~10% ~2-3% 19 NOAA Global Monitoring Division Annual Conference, May 21 2014
Wells with Gas Production Gray dots = wells with gas production 20 NOAA Global Monitoring Division Annual Conference, May 21 2014
Gray dots = wells with oil (liquids) production 21 NOAA Global Monitoring Division Annual Conference, May 21 2014
Gray dots = wells with oil (liquids) production 22 NOAA Global Monitoring Division Annual Conference, May 21 2014
Correlations of C 2 H 6 with CH 4 Survey Flight 10172013 No correlation Significant correlation Use the sum of CH 4 that does NOT correlate with C 2 H 6 (blue) to establish contribution from biogenic sources: ~25%. 23 NOAA Global Monitoring Division Annual Conference, May 21 2014
Conclusions & Future Work Methane emissions for several other basins are going to be published in the next year Barnett Fayetteville, Haynesville, Marcellus (Peischl, in prep.) Bakken, San Juan, Marcellus – upcoming measurements planned Work is still needed to reconcile inventories with estimates based on atmospheric measurements. More work is going to focus on attribution using ethane (U Mich, Aerodyne) and 13CH 4 (Picarro). 24 NOAA Global Monitoring Division Annual Conference, May 21 2014
25 NOAA Global Monitoring Division Annual Conference, May 21 2014
Utah, 2012 High emissions, but this field only represents ~1% of US production. downwind CH 4 (ppb) upwind Distance perpendicular to wind (km) Karion, A., C. Sweeney, et al. (2013). Methane emissions estimate from airborne measurements over a western United States natural gas field. Geophysical Research Letters. 26 NOAA Global Monitoring Division Annual Conference, May 21 2014
Denver-Julesburg, May 2012 Pétron et al., 2014. 27 NOAA Global Monitoring Division Annual Conference, May 21 2014
Summary of Results for O&G Emissions in the D-J Basin Pétron et al., 2014 NMHC C 6 H 6 CH 4 cars 1. Top-down oil and gas emission estimates based on flight data in May 2012 are ~2 times larger than state inventory estimates for NMHCs and 7 times larger for the carcinogen benzene (C 6 H 6 ). 2. CH 4 emissions are close to 3 times larger than an estimate based on EPA GHGRP data. 28
Average Daily NG Production Barnett Shale natural gas comprises 7% of US total production. 29 5/22/2014
19 Oct 2013 30 NOAA Global Monitoring Division Annual Conference, May 21 2014
27 March 2013 Ethane (C 2 H 6 ) Methane (CH 4 ) 31 NOAA Global Monitoring Division Annual Conference, May 21 2014
27 March 2013 CH 4 but no C 2 H 6 in this plume Ethane (C 2 H 6 ) Methane (CH 4 ) 32 NOAA Global Monitoring Division Annual Conference, May 21 2014
27 March 2013 CH 4 and C 2 H 6 are both components of natural gas; CO is not. CH 4 C 2 H 6 CO Downwind Transect 2 Downwind Transect 1 33 NOAA Global Monitoring Division Annual Conference, May 21 2014
27 March 2013 CH 4 but no C 2 H 6 in this plume CH 4 C 2 H 6 CO Downwind Transect 2 Downwind Transect 1 34 NOAA Global Monitoring Division Annual Conference, May 21 2014
Average Daily NG Production 35 NOAA Global Monitoring Division Annual Conference, May 21 2014
Well Count 36 NOAA Global Monitoring Division Annual Conference, May 21 2014
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