ethane emissions estimates from oil and … · methane emissions estimates from oil and natural gas...

METHANE EMISSIONS ESTIMATES FROM OIL AND NATURAL GAS PRODUCTION USING ATMOSPHERIC MEASUREMENTS 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 CH4 emissions?

Methane (CH4) 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.

NOAA Global Monitoring Division Annual Conference, May 21 2014 2

So what are the CH4 emissions from natural gas?

0

1

2

3

1 2 3

% C

H4

Leak

age

Report

DistributionTransmissionProcessingProduction2013 2011 2010

02468

1012

2004 2009

Tg C

H4/

yr

Year

2010Report2011Report2013Report

0

5

10

15

1 2 3

Tg C

H4/

yr

Report

DistributionTransmissionProcessingProduction

2013 2011 2010

EPA Inventory of GHG Sources and Sinks


Mass Balance Approach for Emissions Estimation

∫ ∫+

−

∆=

b

b

z

zairCHCH dxdznXVn

PBL

gnd

44cosθ

Perpendicular wind speed

Wind

emissions

Wind

Background CH4

Downwind CH4

CH4 flux Molar CH4 enhancement in PBL

mixing height (PBL)


TEXas Methane EXperiment


Barnett Shale: 7% of US gas production; one of top 3 shale plays in US

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


Texas Methane Experiment: Aircraft

Purdue Duchess

Scientific Aviation Mooney


19 Oct 2013 Upwind (Duchess)

Downwind (Mooney)


wind

19 Oct 2013

CH4 C2H6

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.

5 downwind transects


Total CH4 Emission


Mean of nine flights

Attribution to oil and gas


10172014

Oil producing wells

Dry gas producing wells

Ethane to Methane Ratio: 19 Oct 2013


Ethane to Methane Ratio: 19 Oct 2013

~10%

~2-3%



Wells with Gas Production

Gra

y do

ts =

wel

ls w

ith g

as p

rodu

ctio

n


Gra

y do

ts =

wel

ls w

ith o

il (li

quid

s) p

rodu

ctio

n

Correlations of C2H6 with CH4


Survey Flight 10172013

Significant correlation

No correlation

Use the sum of CH4 that does NOT correlate with C2H6 (blue) to establish contribution from biogenic sources: ~25%.

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 13CH4 (Picarro).

Utah, 2012

Distance perpendicular to wind (km) C

H4 (

ppb)

downwind

upwind

Karion, A., C. Sweeney, et al. (2013). Methane emissions estimate from airborne measurements over a western United States natural gas field. Geophysical Research Letters.


High emissions, but this field only represents ~1% of US production.

Denver-Julesburg, May 2012

Pét

ron

et a

l., 2

014.


Summary of Results for O&G Emissions in the D-J Basin

28

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 (C6H6).

2. CH4 emissions are close to 3 times larger than an estimate based on EPA GHGRP data.

C6H6 CH4 NMHC

cars

Pétron et al., 2014

Average Daily NG Production

5/22/2014 29

Barnett Shale natural gas comprises 7% of US total production.

19 Oct 2013


27 March 2013

Methane (CH4) Ethane (C2H6)


27 March 2013

Methane (CH4) Ethane (C2H6)

CH4 but no C2H6 in this plume


27 March 2013

CH4

C2H6

CO

CH4 and C2H6 are both components of natural gas; CO is not.

Downwind Transect 1 Downwind Transect 2


27 March 2013

Downwind Transect 1

CH4 but no C2H6 in this plume

Downwind Transect 2

CH4

C2H6

CO


Average Daily NG Production


Well Count


ethane emissions estimates from oil and … · methane emissions estimates from oil and natural gas...

Documents