Use of Photochemical Grid Models for N

New Oil and Gas Wells

Ralph Morris 

ENVIRON International Corporation

rmorris@environcorp.com

EPA’s 9th Conference on Air Quality Modeli

Non-Guideline Applications

October 9, 2008
National Environmental Policy A

 Legislation enacted in 1969 Requires agencies to fully analyze and disclose im

new projects

 Guided by Council on Environmental Quality (CEQ Consultation with public and private parties Disclosure provided through Environmental Assess

and Environmental Impact Statements (EISs)

 Use “Best Science” available

 Potential environmental impacts of Oil and Gas 

developments in the western states disclosed und

 The FLM is responsible for preparing EISs/EAs for 

development projects on federal land. The Bureau Management (BLM) has been most active in this arU.S. Forest Service, Tribes and other agencies are active in this area
NEPA Oil and Gas Exam

Source: Wyoming Oil and Gas Conservation Commission

 Wyoming natural gas production increasi Efforts to increase domestic production o

gas
Background SWWY O&

 The development of an oil and gas production project on fe

usually involves the preparation of an EIS or EA under NEPdiscloses the potential environment effects of the project 

 EIS/EA includes air quality modeling to show project impac

criteria pollutant concentrations, visibility, and deposition 

Drill Rig Natural Gas Processin

Images from Wikipedia
Background: SWWY O&G 

Quality Assessments

 Pre-History <1996: Qualitative 1996 – Moxa Arch: Set Many Precedents 1997 – 1st Jonah & Pinedale Anticline EIS 

– Pinedale Anticline mitigates visibility impacts through purchase of low 

Bridger coal-fired generating station

 1997 – 1999 – SWWYTAF

– Develop CALPUFF Database for SWWY

 1999 Continental Divide & SUIT

– First to Use CALPUFF for Cumulative Analysis

 2000: FLAG guidance Issued 2004 – 2006 Jonah Infill EIS 2005 Ozone exceedances recorded in Pinedale area 2007 Pinedale Supplemental EIS

– First to address ozone using PGM

 2007-2008 – 4-Corners Interagency AQ Task Force Analysis 2008 – 2009 Planned: Continental Divide-Creston EIS

– Use PGM for air quality, visibility and deposition (No CALPUFF)
EIS Air Quality Modeling

 Until recently, EIS AQ impact assessments used AERM

field impacts and CALPUFF for far-field AQ and AQRV i

 High ozone concentrations have been observed in south

Wyoming

 AERMOD/CALPUFF do not simulate ozone formation

8-Hour Ozone Measured at the Jonah Monitor in 

Southwest Wyoming: February, 2005

0

102030405060708090

100

1 2 3 4 5 6 7 8 10 11 12 13 14 15 16 17 19 20 21 22 23 24 25 26 28

Day

8-Hour Ozone (ppb)
Southwest Wyoming O&G 
2006+ SWWY O&G Develo

 2006 Moxa Arch and Hiawatha (MA&H) O&G Infil

– Use AERMOD for near-source AQ and CALPUFF for far

AQRV

 2005-2006 ozone exceedances recorded in SWW 2007 ozone analysis added to MA&H using PGM

– Leverage off of WRAP 2002 PGM database

 2007+ proposed Continental Divide-Creston O&G

– First EIS to proposed using PGM for ozone and all far-fie

AQRV (still use AERMOD for near-source AQ)

 2008 MA&H also adopt PGM approach for ozone 

AQ and AQRV

– Need to redo ozone/AQ/AQRV analysis due to emission 

lack of adequate cumulative inventory to address ozone

– CD-C PGM and emissions database development availa
Continental Divide-Cres

 Proposed natural gas project in southern 

Wyoming: 8,950 new wells

 First EIS to propose to use photochemica

model to perform both ozone and AQ/AQimpact analysis

 Comprehensive emission inventory for oi

production sources in southwest Wyominfield-specific information supplied by the producers

 2005 & 2006 36/12/4 MM5 meteorologica

modeling
2006 Drill Rig Locations:

5 County SWWY
2006 Producing Wells:

5 County SWWY
MM5 Modeling Domains

 3 nested grid 36 km grid is 

national grid

 12 km doma

enough to enCD-C 4 km dwell as those O&G Basins 

 4 km domain 

on SWWY

-3000 -2000 -1000 0 1000 2000 3000

-2000-1000

0

10002000

GIANT MM5 36km

GIANT MM5 12km

CD-C MM5 04km

2005 and 2006 Calendar Years
Copyrighted page/s removed. Copyrighted material is not available in 

Regulations.gov since it may not be reproduced without consent of 

the copyright holder. 

Contact the EPA Docket Center’s Public Reading Room to view 

or receive a copy of this document. 

Requests for copies may be made as follows: 

In person/writing: 

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1301 Constitution Ave NW, 2822T, Room 3334 

Washington, DC. 20004 

Telephone: 

202-566-1744 

Fax: 

202-566- 9744 

Email: 

docket-customerservice@epa.gov 
Winds at Jonah: 4 km Grid

Observed MM

4 km

 MM5 4km run shows good direction performance, 

wind speed bias for peak wind speeds

 Improvement over 4 km CALMET runs using 12 k

data 

NORTHSOUTH

WEST EAST

5%

10%

15%

20%

25%

WIND SPEED(Knots)

>= 2217 - 2111 - 177 - 114 - 71 - 4

Calms: 5.77%

CALMET 

4 km
36/12/4 km CD-C PGM Dom
CD-C 12/4 km PGM Dom

 Impact assessm

focus on ozone and AQ/AQRV Class I and senareas

– AERMOD still 

source impacts

 12/4 km domain

that the inputs dthe CD-C projecused for other E

– Moxa Arch– Hiawatha– Other?

 Consistency am

assessments

 Using best scie
PGM Configuration

 MM5 36/12/4 km meteorology (2005 & 200 CB05 gas-phase and RADM aqueous-pha

chemical mechanisms and ISORROPIA aethermodynamics

 Boundary conditions on 36 km grid from gl

chemistry model

 How to simulate winter high ozone events 

SWWY?

– Clear Skies– Snow on ground– Strong surface inversion– High VOC and NOx concentrations
SWWY EIS Modeling Chall

 Monitoring network n

as is typical for urba

– How to use EPA-gui

approach using relatresults?

– How to perform mod

 How to obtain projec

cumulative impacts?

– Use ozone and PM s

apportionment to obtcontributions

 How to address ozon

current measuremen(75 ppb) ozone NAA

– Need Projects that re

(existing decline plus wells)

– Ozone source appor

assess Project’s conozone exceedances
PGMs in NEPA-Related Stu

 Comprehensive Air-quality 

Model with extensions (CAMx; www.camx.com) 

for SWWY and Four Corners region

 Community Mul

Quality (CMAQ) Uinta Basin Air QStudy (www.cmascene
Conclusions

 Recent advances allows for the more routine use of PGM

EIS/EA air quality assessments – Represents best science – Advances in PGM modeling features

Two-way grid nestingFlexi-nestingPlume-in-GridOzone and PM source apportionment – Advances in database availability and expertiseRPO databases (e.g., WRAP) – Advances in computingDoubling computing speed every 18 months – Advances in PGM softwareMM5/WRF meteorological; SMOKE/CONCEPT emissions; post

 Current NEPA-related studies demonstrate utility of PGMs – BLM Moxa Arch and Hiawatha EISs in SWWY – Uinta Basin Air Quality Study (UBAQS) Utah – Four Corners Air Quality Task Force NM/CO – BLM/WDEQ Continental Divide Creston EIS SWWY
Acknowledgements

 We acknowledge the assistance of nume

groups to make the use of PGMs routine EISs/EAs

– Bureau of Land Management (BLM)– U.S. Environmental Protection Agency (EPA)– Wyoming Department of Environmental Quali– Colorado Department of Health and Environm

(CDPHE)

– New Mexico Environmental Department (NME– BP and other Operators– Sage Environmental Consulting– SWCA Environmental Consultants