2013 Western Air Quality Modeling Workshop Technical

2013 Western Air Quality Modeling Workshop Technical Methods and Applications

Boulder, CO July 11, 2013

Jennifer Snyder and Roy Huntley

Emission Inventory and Analysis Group, US EPA

Background ◦ Growth in industry, with previously uncharacterized

emissions ◦ National Oil and Gas Committee

Tool Structure ◦ Flexibility needed due to variability ◦ Calculations

Results ◦ Comparisons to previous years and state

submissions

OAQPS, Emissions Inventory and Analysis Group 2

Major emission sources associated with O&G have traditionally been included as point sources (processing plants, compressor stations, refineries)

Activities occurring upstream have not been well characterized on a national level (see OIG report, “EPA Needs to Improve Air Emissions Data for the Oil and Natural Gas Production Sector,” February 20, 2013.)


◦ Formed in 2011 to develop the O&G inventory ◦ Members from WRAP, MARAMA, CenSARA,

ERTAC ◦ Experts in Oil and Gas inventories from states ◦ Acted as advisory group to EPA; Facilitated

review of the tool by states



Nonpoint Emissions Inventory on a county/basin level

Calculates NOx, VOC, PM, CO, SO2, HAP, H2S, for 2011 ◦ National Defaults based on New Source

Performance Standards/EPA data where possible ◦ CENSARA survey data ◦ HPDI (Drillinginfo) production data

MS Access database Development started with CENSARA tool


Emission Factors: ◦ Gas composition profiles can vary by basin/county

Equipment: ◦ Types of well (e.g., coal bed methane (CBM),

conventional, fracked) ◦ Types and number of pieces of equipment (e.g., fewer

compressors in PA) ◦ Control efficiencies

Production: ◦ (e.g., higher oil production in ND, CBM in NM)

States can override EPA defaults with their own values


Artificial Lift Engines Wellhead Compressor

Engines Lateral Compressor Engines Drilling Rigs Condensate Tanks Hydraulic Fracturing Pumps Well Completion Venting Liquids Unloading Associated Gas Venting Dehydrators Pneumatic Devices

Heaters Crude Oil Tanks Produced Water Tanks Gas-Actuated Pneumatic

Pumps Fugitive Emissions Mud Degassing Hydrocarbon Liquids

Loading Flaring (when used to

control emissions from the unit processes listed above)

It should be noted that these source categories do not represent a complete list of all emission sources that may be found at upstream oil and gas exploration and production sites. Future versions of the tool may include additional processes.


Salt water injection engines, well pad construction equipment, workover equipment and associated mobile sources.

Associated onroad mobile sources operating in the field, such as service vehicles used during construction, drilling and production phases, may be included in some states’ mobile source emissions inventories but are not specifically included in this inventory.


where:

Eengine are emissions from a particular type (rich vs. lean) of compressor engine [ton/year/engine]

EFi is the emissions factor of pollutant i [g/hp-hr]

HP is the horsepower of the engine [hp]

LF is the load factor of the engine

tannual is the annual number of hours the engine is used [hr/yr]

Fcontrolled is the fraction of compressors of a particular type (rich vs. lean) that are controlled

CFi is the control factor for controlled engines for pollutant i

907,185 is the unit conversion factor g/ton

)1(185,907, icontrolled

annualitypeengine CFFtLFHPEFE ×−×

×××=


HPDI ◦ Consistent ◦ Obtained from state oil and gas commission ◦ Provides oil and NG produced, condensate and

associated gas, oil, NG and CBM well counts, completions, produced water, feet drilled

CenSARA Survey ◦ Counts, efficiencies of equipment

EPA Data ◦ NG composition profiles ◦ Emission factors

State Data ◦ State oil and gas commission information ◦ TCEQ and CENRAP studies


VOC Emissions 2011 Oil and Gas Tool

12 OAQPS, Emissions Inventory and Analysis Group

>= 0 to <= 100 TPY >100 to <= 1,000 >1,000 to <= 5,000 >5,000 to <= 25,000 >25,000

NOx Emissions 2011 Oil and Gas Tool

OAQPS, Emissions Inventory and Analysis Group

>= 0 to <= 100 TPY >100 to <= 500 >500 to <= 2,500 >2,500 to <= 10,000 >10,000

13

Pollutant

State-submitted 2011 Data1

PM NAAQS Modeling

(2007)

2008 NEI v3

2011 EPA

Tool

Point Nonpoint Total Nonpoint Nonpoint Nonpoint

NOX 23,015 467,256 490,272 369,738 385,439 882,249

VOC 43,637 1,747,131 1,790,768 1,762,596 1,648,386 2,925,315

CO 23,894 419,300 443,194 1,040,553

SO2 55,255 13,276 68,532 7,231

1As of May 2013


In general, higher emissions, and this is makes sense… ◦ Better national coverage New high production states such as Alaska and

North Dakota are covered ◦ More complete set of source categories covered

(SCCs) ◦ O&G production continues to grow

Continued improvements in tool is likely to see both increases and decreases

Much stronger case overall sector estimates


0

200000

400000

600000

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1000000

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CA CO KS LA MO NY OH OK PA TX UT WY

Tons

VO

C

NP State Submissions

Oil and Gas Tool



0

50000

100000

150000

200000

250000

300000

CA CO KS LA MO NY OH OK PA TX UT WY

Tons

NO

x

NP State Submissions

Oil and Gas Tool

◦ Generally similar emissions on a state level ◦ Some states showed great differences Wyoming California Texas Pennsylvania ◦ We are still reviewing state submittals ◦ In general, our policy is to use state data over

EPA defaults If we have questions, we generally discuss with State

before using EPA data


0

1E+09

2E+09

3E+09

4E+09

5E+09

6E+09

7E+09

8E+09

0

100000

200000

300000

400000

500000

600000

700000

800000

900000

1000000 AK

AL

AR

AZ

CA

CO

FL

GA

IL

IN

KS

KY

LA

M

D

MI

MN

M

O

MS

MT

ND

N

E N

M

NV NY

OH

O

K O

R PA

SD

TN

TX

UT

VA

WV

WY

SumOftotal_emissions Oil (.1 BBL) Gas Well Gas (MCF) CBM Gas (MCF) OAQPS, Emissions Inventory and Analysis Group 19

0

1E+09

2E+09

3E+09

4E+09

5E+09

6E+09

7E+09

8E+09

0

20000

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AK AL AR AZ CA CO FL IL IN KS KY LA MD MI MN MO MS MT ND NE NM NV NY OH OK OR PA SD TN TX UT VA WV WY

SumOftotal_emissions Oil (0.1 BBL) Gas Well Gas (MCF) CBM Gas (MCF) OAQPS, Emissions Inventory and Analysis Group 20

Source Category NOX (TPY) VOCs (TPY) Total HAP (TPY)

Artificial Lifts 105,684 1,378 1,510

Associated Gas 30 32,722 85

Condensate Tanks 452 464,065 4,957

Crude Oil Tanks 110 769,805 20,298

Dehydrators 71,172 84,147 53,497

Drill Rigs 80,129 4,852 1,054 Fugitives 144,552 768

Gas-Actuated Pumps 164,739 980

Heaters 119,631 6,580 3,117

Hydraulic Fracturing 5,523 349 76 Lateral/Gathering Compressor Engines 133,883 3,921 2,750

Liquids Unloading 133 159,633 439 Loading Emissions 0 64,606 816

Mud Degassing 0 81,696 179 Pneumatic Devices 0 788,866 5,328

Produced Water 0 57,840 233 Well Completions 734 82,254 637

Wellhead Compressor Engines 364,768 13,313 10,481

Total 882,250 2,925,316 107,205


Artificial Lifts, 105,684

Associated Gas, 30

Condensate Tanks, 452

Crude Oil Tanks, 110 Dehydrators ,

71,172 Drill Rigs, 80,129

Heaters, 119,631

Hydraulic Fracturing,

5,523

Lateral/ Gathering

Compressor Engines, 133,883

Liquids Unloading,

133

Well Completions,

734

Wellhead Compressor

Engines, 364,768


Associated Gas 32,722

Condensate Tanks 464,065

Crude Oil Tanks 769,805

Dehydrators 84,147

Fugitives 144,552

Gas-Actuated Pumps 164,739

Heaters 6,580

Liquids Unloading 159,633

Loading Emissions

64,606

Mud Degassing

81,696

Pneumatic Devices , 788,866

Produced Water 57,840

Well Completions 82,254

Wellhead Compressor

Engines 13,313


EPA currently gathering information on available studies/analyses for larger basins

EPA needs a future inventory quickly ◦ By early to mid-August ◦ Future year TBD, but likely in 2018-2022 timeframe ◦ Focus on largest basins or basins expected to undergo the

most significant change (less or more) vs. 2011 ◦ Alternatively, a high-level, quick to implement projection

strategy would be useful, by: State, county or basin And/or SCC

Default is to use 2011 NEI (point and non-point) Oil & Gas as-is for all future years

Longer-term (end of 2013), would prefer more robust projected inventory, possibly out to 2030


VOC Speciation ◦ Basin-specific VOC speciation from WRAP Phase III

project ◦ Looking to develop/best-match non-WRAP oil & gas

basins based on characteristics (wet vs dry gas vs coal bed methane, production cycle, other?)

Spatial Allocation ◦ 2km-based shapefile developed for WRAP Phase III &

Permian basins ◦ 2km HIS-based shapefile developed for Northeastern

Region (includes Marcellus) ◦ Fallback to existing IHS & USGS Oil & Gas Wells surrogate

Temporal Allocation ◦ Annual to monthly, day-of-week, and diurnal based on

existing SCC assignments and 2007 platform profiles


Public release in July 2013 expected to generate comments for future improvements

National Committee comments and concerns are being recorded and prioritized for future updates ◦ Addition of Coal Bed Methane distinction between wells ◦ New Survey Data coming from BLM/WRAP in summer ◦ Incorporate new state/RPO data

EPA plans to continue improving this tool and O&G emission estimates (Version 2 to be released in Spring 2014)

Emission controls-task to improve control information in 2014 NEI

EPA resource constraints could make improvements slower than we would like


Documents

2013 Western Air Quality Modeling Workshop Technical