# Drilling Rig Emission

Inventory for the State of

Texas

Final Report

Prepared for:

Texas Commission on Environmental

Quality

Prepared by:

Eastern Research Group, Inc.

July 15, 2009

# Drilling Rig Emission Inventor y for the State of Texas

Final Report

Prepared for:

Greg Lauderdale

Texas Commission on Environmental Quality

P. O. Box 13087

Austin, TX 78711-3087

Prepared by:

Rick Baker

Mike Pring

Eastern Research Group, Inc.

5608 Parkcrest Drive, Suite 100

Austin, TX 78731

July 8, 2009

# Table of Contents

LIST OF ACRONYMS ................................................................................................................. iii

1.0 Executive Summary ......................................................................................................... 1-1

2.0 Introduction ...................................................................................................................... 2-1

3.0 Review of Existing Literature .......................................................................................... 3-1

3.1 Review of Existing Studies .................................................................................. 3-1

3.2 Review of Existing Data ...................................................................................... 3-2

3.3 Drilling Rig Overview ......................................................................................... 3-3

4.0 Data Collection Plan ........................................................................................................ 4-1

4.1 Participant Recruitment ....................................................................................... 4-1

4.2 Phone/Email Surveys ........................................................................................... 4-1

4.3 Confidentiality ..................................................................................................... 4-2

5.0 Data Collection Results .................................................................................................... 5-1

5.1 Survey Findings ................................................................................................... 5-1

5.2 Model Rig Category Development ...................................................................... 5-3

5.3 Fracturing ............................................................................................................. 5-6

6.0 Emissions Inventory Development and Results .............................................................. 6-1

6.1 Activity Data ........................................................................................................ 6-1

6.1.1 2008 Base Year Activity .......................................................................... 6-1

6.1.2 2002 and 2005 Prior Years Activity ........................................................ 6-1

6.1.3 2009 through 2021 Projected Activity ..................................................... 6-3

6.1.4 2002, 2005, and 2008 through 2021 Activity Summary ..........................6-6

6.2 Model Rig Emission Profiles ............................................................................. 6-12

6.2.1 Model Rig Engine Profiles ..................................................................... 6-12

6.2.2 Model Rig Emission Factors .................................................................. 6-14

6.3 Emission Estimation Methodology .................................................................... 6-17

6.4 Results ................................................................................................................ 6-19

6.4.1 Emission Summary ................................................................................ 6-19

6.4.2 NIF 3.0 Files .......................................................................................... 6-19

7.0 Conclusions and Recommendations ................................................................................ 7-1

8.0 References ........................................................................................................................ 8-1

Appendix A – Approved Data Collection Plan

Appendix B – Survey Letter

Appendix C – Drill Rig Survey Form

Appendix D – Survey Data

Appendix E – Total Drilling Depth by County by Model Rig Well Type Category

Appendix F – Emission Factors

Appendix G – Annual and OSD Co unty-Level Emission Estimates

i

# List of Tables

Table 1.1 Drilling Rig Estimates (tons/year) ............................................................................... 1-2

Table 3.1 Existing Oil and Gas Exploration Emissions Studies .................................................. 3-1

Table 5.1 Survey Summary Statistics .......................................................................................... 5-3

Table 5.2 Model Rig Category Statistics ..................................................................................... 5-5

Table 6.1 2002 and 2005 Prior Year Activity Scaling Factors .................................................... 6-3

Table 6.2 Projected Crud e Oil Production 2008-2021................................................................. 6-5

Table 6.3 Projected Natura l Gas Production 2008-2021 ............................................................. 6-5

Table 6-4 Projected Growth Factors 2009-2021 .......................................................................... 6-7

Table 6.5 2008 Total Depth by Model Rig Well Type Category (1,000 feet) ............................. 6-8

Table 6.6 Model Rig Engine Parameters ................................................................................... 6-14

Table 6.7 PM 10 

# Speciation Factors ............................................................................................ 6-16

Table 6.8 TOG Speciation Factors ............................................................................................. 6-16

Table 6.9 TxLED Counties ........................................................................................................ 6-17

Table 6.10 Texas Drilling Rig Estimates (tons/year) ................................................................. 6-20

Table 6.11 2008 Annual and OSD County-Leve l Criteria Pollutant Emission Estimates ......... 6-21

List of Figures

Figure 5.1 Counties with Survey Data ......................................................................................... 5-4

Figure 6.1 TRC District Map ....................................................................................................... 6-2

Figure 6.2 EIA Regions ............................................................................................................... 6-4

ii

# iii 

# LIST OF ACRONYMS

Acronym Definition

API American Petroleum Institute

CARB California Air Resources Board

CO Carbon Monoxide

DOE U.S. Department of Energy

EIA Energy Information Administration

ERG Eastern Research Group

HAP Hazardous Air Pollutant

hp Horsepower

IADC International Associat ion of Drilling Contractors

MMBBL Million Barrels

NEI National Emissions Inventory

NIF NEI Input Format

NO

x 

# Nitrogen Oxides

OSD Ozone Season Daily

PM 10 

# PM with particle diameter less than 10 micrometers

PM 2.5 

# PM with particle diameter less than 2.5 micrometers

SCC Source Classification Code

SIP State Implementation Plan

SO 2 

# Sulfur Dioxide

TCEQ Texas Commission on Environmental Quality

TexAER Texas Air Emissions Repository

TIPRO Texas Independent Producers and Royalty Owners Association

TOG Total Organic Gases

TRC Texas Railroad Commission

TxLED Texas Low Emission Diesel

TXOGA Texas Oil and Gas Association

US EPA United States Environmental Protection Agency

VOC Volatile Organic Compounds

WRAP Western Regional Air Partnership

# 1.0 Executive Summary

The purpose of this study was to develop a comprehensive emissions inventory for

drilling rig engines associated wi th onshore oil and gas explorati on activities occurring in Texas

in 2008. Oil and gas exploration and production faci lities are considered some of the largest

sources of area source emissions in certain geog raphical areas, dictating the need for continuing

studies and surveys to more accurately depict these activities. A 2005 base year oil and gas

emissions inventory developed for the Texas Commission on Environmental Quality (TCEQ) by

Eastern Research Group (ERG) in 2007 (TCEQ, 2007) was comprehensive in coverage of all

exploration and production facility and equipment types, including drilling rig engines. However,

that project relied on data from secondary source s with assumptions applied to represent local

activities. The Western Regional Air Partnership (WRAP) devel oped a comprehensive emissions

inventory of oil and gas explora tion and production facilities for th e western states that did not

include Texas, although the previous ERG study did make use of the WRAP results in terms of

methodology and emission factors where practicable.

The current inventory effort built off of the previous 2007 study, focusing exclusively on

drilling activities. The previous effort was expanded upon by improving both the activity data

(well counts, types, and depths ) used to estimate emissions, and through the development of

updated drilling rig engine emi ssion profiles. The improved well activity data was obtained

through acquisition of the “Drilli ng Permit Master and Trailer” database from the Texas Railroad

Commission (TRC), while the impr oved drilling rig emissions ch aracterization profiles were

obtained through a survey of oil and gas explorat ion and production companies. The activity data

and emissions characterization data were then us ed to develop the drillin g rig engine emissions

inventory for a 2008 base year.

In order to survey drilling rig contractors and oil and gas operators across the state, ERG

purchased contact information for companies that were active in well drilling activities that

occurred in Texas in 2008 through a commercial vendor (RigData ® 

# ). Through phone and email

surveys, ERG obtained 45 drilling rig profiles representative of over 1,500 wells drilled in Texas

in 2008.

The survey effort itself focused on colle cting the following information from each

respondent:

• The number of engines on a rig

• Engine make, model, model year, and size (hp)

• Average load for each engine

1-1

# • Engine function (draw works, mud pumps, power)

• Actual engine hour data for each well (total hours)

• Actual engine fuel use data for each well (total fuel use)

• Total well drilling time (actual number of drilling days)

• Total well completion time (number of days needed for well completion activities)

• Well depth

• Number of wells represented by survey

Target pollutants for this inventory include nitrogen oxides (NO X 

# ), volatile organic

compounds (VOC), carbon monoxide (CO), particulate matter (PM 10 

# and PM 2.5 

# ), sulfur dioxide

(SO 2 

# ), and hazardous air pollutants (HAP). Emissions were calculated for each county in Texas

where drilling occurred in 2008 a nd are provided in a nnual tons per year and by typical ozone

season day. For planning purposes, the 2008 base y ear estimates were used to develop 2002 and

2005 prior year inventories, as well as pr ojected inventories for 2009 through 2021. 2002 and

2005 prior year inventories were based on TRC r ecords of oil and gas well completions during

those years, and U.S Department of Energy (DOE), Energy Inform ation Administration (EIA) oil

and gas production growth estimates were used to develop the projecti ons for future years 2009

through 2021.

Emissions estimates developed from this in ventory project may be used for improved

input data to photochemical air quality dispersi on modeling, emissions sensitivity analyses, State

Implementation Plan (SIP) development, and ot her agency activities. The final 2002, 2005, and

2008 base year inventory estimates are provided in National Emissions Inventory (NEI) Input

Format (NIF) 3.0 to facilitate entry of the data into the state’s TexAER ( Tex as A ir E missions

R epository) database, and for the purposes of submittal to US EPA. For purposes of NIF

preparation, Source Classificat ion Code (SCC) 23-10-000-220 (I ndustrial Processes - Oil and

Gas Exploration and Production - All Processe s - Drill Rigs) was used as provided by TCEQ

(TCEQ, 2009).

Table 1-1 summarizes the statewide a nnual emission estimates for 2002, 2005, and 2008

through 2021.

Table 1.1 Drilling Rig Estimates (tons/year)

Year CO NO

x 

# PM 10 

# PM 2.5 

# SO 2 

# VOC

2002 13,305 35,828 2,552 2,475 4,776 3,631

2005 15,878 42,854 3,036 2,945 5,977 4,337

2008 16,721 55,238 2,543 2,467 956 4,326

2009 16,769 55,457 2,550 2,474 961 4,340

2010 16,336 53,123 2,417 2,344 45 4,182



# 1-2

# 1-3 Table 1.1 Drilling Rig Estimates (tons/year) (Continued)

Year CO NO

x 

# PM 10 

# PM 2.5 

# SO 2 

# VOC

2011 15,117 48,462 2,319 2,249 44 3,806

2012 14,748 46,253 2,263 2,196 43 3,665

2013 12,008 39,793 1,378 1,337 38 3,413

2014 11,945 39,461 1,372 1,331 38 3,392

2015 11,755 38,837 1,350 1,310 37 3,349

2016 11,558 36,440 1,320 1,280 37 3,320

2017 8,915 34,771 1,118 1,085 36 2,800

2018 6,114 31,282 811 787 35 2,227

2019 6,073 31,127 805 781 35 2,215

2020 6,035 30,771 800 776 35 2,205

2021 3,299 26,063 448 435 33 1,504

# 2.0 Introduction

The purpose of this study was to develop a comprehensive emissions inventory for

drilling rig engines associated wi th onshore oil and gas explorati on activities occurring in Texas

in 2008. Oil and gas exploration and production faci lities are considered some of the largest

sources of area source emissions in certain geog raphical areas, dictating the need for continuing

studies and surveys to more accurately depict these activities. A previous study conducted by

Eastern Research Group (ERG) in 2007 under TC EQ contract 582-7-84003, Work Order 01 was

comprehensive in coverage of all the explora tion and production facility and equipment types,

including drilling rig engines, a lthough this project relied on data from secondary sources with

assumptions applied to represent local activ ities (TCEQ, 2007). Th e Western Air Regional

Partnership (WRAP) developed a comprehensive emissions inventory of oil and gas exploration

and production facilities for the we stern states that di d not include Texas, although the previous

ERG study did make use of the WRAP study in terms of methodology and emission factors

where practicable.

While drilling activities are ge nerally short-term in dura tion, typically covering a few

weeks to a few months, the associated diesel engines are usually very large, from several

hundred to over a thousand horsepower. As such, drilling activities can ge nerate a substantial

amount of NO

x 

# emissions. While previous studies have focused more intently on quantifying the

ongoing fugitive VOC emissions associated with oil and gas production, significant uncertainty

remains regarding the shorter term NO

x 

# emission levels associated with drilling activity.

In order to gain a more accurate understandi ng of emissions from drilling rig engines,

data regarding typical rig profile s (number of engines, engine si zes, and engine load factors)

were collected through phone and email surveys for drilling operations for the 2008 base year.

These data were used to deve lop well drilling emissions prof iles using US EPA’s NONROAD

emissions model. 1 

# To develop the statewide emissions inventory, the drilling rig emissions

profiles developed as a result of the survey we re applied to well dril ling activity data for 2008

obtained from the Texas Railroad Commission (TRC).

The activity and drilling rig engine emissi ons profiles developed under this study were

used to develop emissions estimates of vol atile organic compounds (VOC), nitrogen oxide

(NO

x 

# ), carbon monoxide (CO), particulate matter (PM 10 

# and PM 2.5 

# ), sulfur dioxide (SO 2 

# ), and

1 

# While the NONROAD model was used to calculate drilling activity emissions (in order to more accurately capture

emission standard phase in impacts), th ese emissions are actually classified as area sources emissions and reported

as such to the TCEQ.



# 2-1

# 2-2 hazardous air pollutants (HAP) for drilling rig engines across the stat e. Emissions are calculated

on a county-level basis and provided in annual to ns per year and by typical ozone season day.

For planning purposes, the 2008 base year estim ates were used to develop 2002 and 2005 prior

year inventories, as well as projected inventories for 2009 through 2021.

Section 3.0 of this report provides the results of a review of existing literature as well as

currently available data that could be used to develop the inventor y. This discussion also

provides an overview of the drilli ng process and identifies the t ypes of activities and equipment

that are commonly associated with drilling activity. Sec tion 4.0 provides an overview of the data

collection plan and the subsequent survey that was used to obtain the information needed to

develop the model drilling rig emi ssions profiles. Section 5.0 presen ts the results of the survey,

including a discussion of how the data was broke n down into distinct “m odel” drilling rigs by

well type and depth. Section 6.0 de scribes the development of th e emissions inventory including

how the activity data was compiled, how the model drilling rig emission profiles were

developed, and how these model drilling rig emissi on profiles were combined with the activity

data to develop the 2002, 2005, and 2008 through 2021 emission inventories.

# 3.0 Review of Existing Literature

At the start of this study ERG conducted a review of relevant literature, current studies,

and available data that could be used in the development of a drilling rig engine emissions

inventory for Texas. The results of this resear ch are discussed below in Sections 3.1 through 3.3.

Section 3.1 discusses the review of existing studies concerning es timating emissions from oil and

gas drill rig operations, Section 3.2 covers the results of the re view of existing Texas data

available from government and industry websit es and publications, and Section 3.3 includes a

discussion of drilling rigs and the types of e ngines and activities occurring during a drilling

operation.

3.1 Review of Existing Studies

Over the last several years numerous studies ha ve been conducted in the western states to

develop area source emission estimates for oil and gas exploration and production sources, with

subsequent studies improving upon the data collection methodology and emission estimation

approaches. Most of these studies addressed emissions from drilli ng rig engines to some degree.

The relevant studies ERG identif ied are listed in Table 3-1.

Table 3.1 Existing Oil and Gas Exploration Emissions Studies

Report Title Geographic

Coverage Publication Date

Oil and Gas Emission Inventories for the Western

States (Russell, et al., 2005) WRAP States December, 2005

Ozone Precursors Emission Inventory for San

Juan and Rio Arriba Counties, New Mexico

(Pollack, et al., 2006) San Juan and

Rio Arriba

Counties,

New Mexico August, 2006

Emissions from Oil and Gas Production Facilities

(TCEQ, 2007) Texas August, 2007

WRAP Area Source Emissions Inventory

Projections and Control Strategy Evaluation

Phase II (Bar-Ilan, et al., 2007) WRAP States September, 2007

Development of Baseline 2006 Emissions from

Oil and Gas Activity in the Denver-Julesburg

Basin (Bar-Ilan, et al., 2008) DenverJulesburg

Basin,

Colorado April, 2008

Recommendations for Improvements to the

CENRAP States’ Oil and Gas Emissions

Inventories (Bar-Ilan, et al., 2008a) CENRAP

States November, 2008



# 3-1

# Table 3.1 Existing Oil and Gas Expl oration Emissions Studies (Cont.)

Report Title Geographic

Coverage Publication Date

Development of Baseline 2006 Emissions from

Oil and Gas Activity in the Piceance Basin (BarIlan, et al., 2009) Piceance

Basin,

Colorado January, 2009



# Based on a review of these studies, ERG devel oped a series of survey questions to obtain

the types of data that would be needed to de velop the 2008 base year emissions inventory. The

resultant survey was developed using example surv ey questions and forms from several of these

existing studies.

The studies identified in Table 3-1 were co mprehensive in nature, inclusive of all

emission sources found at oil and gas exploratio n and production locatio ns. While drilling rig

engines were typically included in these studies, this source category was not the primary focus

of these efforts, as these inventories addresse d emissions sources asso ciated with both the

exploration and production sides of the oil and ga s industry. As such, many of the surveys used

in these studies were sent to th e oil and gas producers themselves, and not directly to the owners

and operators of the drill rigs, w ho are typically contracted by th e producers to drill the well. As

described below in Section 5, ERG focused this survey effort on the drilling contractors

themselves, who are most familiar with drilling equipment and activities, with less emphasis on

the production companies.

3.2 Review of Existing Data

All exploratory oil and gas drilling in Te xas requires a permit. These permits are

processed and maintained through the TRC. The dr illing permits are available for review through

the TRC website, and include well-specific data such as approval date, location (county), well

profile (vertical, horizontal, dir ectional), well depth, start or “spud-in” date, and well completion

date. On March 10, 2009, ERG obtained this data in electronic format through acquisition of the

“Drilling Permit Master and Trailer” database. This database formed the basis of the activity data

used to develop the 2008 base year emissions inventory.

In addition to the drilling permit data obt ained through the TRC, many of the larger

drilling contractors provide information about their drilling rig fleets in their on-line websites.

Examples of these websites are provided in th e approved Data Collection Plan, which is included

as Appendix A of this report. ERG reviewed this on-line information in an effort to gain a better

understanding of typical drilling rig engine profiles, including the size, number, and type of

3-2

# engines used on typical rigs. A dditional information provided included make and model of the

engines. Engine manufacturer webs ites were also reviewed and pr oved useful as a resource to

obtain engine specifications and fuel usage data that could be used to gapfill the data obtained

during the survey and needed to complete the emissions inventory. For example, engine fuel

usage data could be used to determine load percentages for engines where the operator provided

fuel use data but did not provide load estimates.

3.3 Drilling Rig Overview

Air pollutant emissions from oil and ga s drilling operations originate from the

combustion of diesel fuel in the drilling rig engi nes. The main functions of the engines on an oil

and gas drilling rig are to provide power for hoisting pipe, circul ating drilling fluid, and rotating

the drill pipe. Of these operations, hoisting and dr illing fluid circulation require the most power.

There are two common types of rigs currently in use

– mechanical and electrical. In general, mechanical rigs

have three independent sets of engines. The first set of

engines (draw works engines) ar e used to provide power to

the hoisting and rotating equipm ent, a second set of engines

(mud pump engines) are dedicate d to circulating the drilling

fluid which is commonly referre d to as “mud”, and a third

set of engines (generator engine s) are used to provide power to auxiliary equipment found on the

drill site such as lighting equipment and heati ng and air conditioning for crew quarters and office

space. There may be one, two, or more draw works engines, depending on the input power

required. There are typically two mud pumps for land rigs, with each mud pump independently

powered by a separate engine. The mud pump engi nes are typically the largest engines used on a

mechanical rig. Finally, there ar e typically two electric generato r engines per mechanical rig,

with one running continuously and th e second serving as a stand by unit.

Electrical rigs are typically comp rised of two to three large, identical diesel-fired enginegenerator sets that provide electr icity to a control house called a si licon controlled rectifier (SCR)

house. Electricity from the SCR house is then used to provide power to separate motors on the

rig. In this configuration, ther e are dedicated electric motors used for the draw works/hoisting

operations, the mud pumps, and other ancillary power needs (such as lighting). The generator

engines are loaded as required to meet fluc tuating power demands, w ith one unit typically

designated for standby capacity. The trend in ne w rig design is almost exclusively towards

electric rigs, except perhaps for the smallest rigs. This is probably due to the relative expense of Draw Works engines

– used to power hoisting and

rotating equipment

Mud Pump engines – used

to circulate drilling fluid

Generator engines – used to

power auxiliary equipment

3-3

# engines versus motors, both in terms of initial cost and maintenance. Today, electrical rigs are

common, especially for larg er rigs (Bommer, 2008).

After drilling and casing a well, it must be “completed.” Completion is the process in

which the well is enabled to produce oil or gas. Once the desired well depth is reached, the

geological formation must be tested and eval uated to determine whet her the well will be

completed for production, or plugged and aband oned. To complete the well production, casing is

installed and cemented and the main drilling rig is dismantled and moved to the next site. A

smaller rig, called a completion rig (also known as a workover rig), is then moved on site to

bring the well into production, to perforate the production casi ng and run production tubing to

complete the well. Typically, the completion ri g is a carrier-mounted arrangement and may be

on-site for several days to a week or more depending on well depth and other factors. The

completion rigs hoist smaller loads and pump at lower rates than the drilling rigs, and therefore

require much smaller engine capacity.

Increasingly, reservoir productivity is enha nced by the application of a stimulation

technique called hydraulic fractur ing. In this process, the re servoir rock is hydraulically

overloaded to the point of rock fracture. The fract ure is induced to propagate away from the well

bore by pumping hydraulic fracturing fluid into the well bore under hi gh pressure. The fracture is

kept open after the end of the job by the introduc tion of a solid proppant (sand, ceramic, bauxite,

or other material), by eroding the sides of the fracture walls and creatin g rubble by high injection

rates, or for carbonate formations, by etching the walls with acid. The frac ture thus created and

held open by the proppant materials becomes a high conductivity pathway to the well bore for

reservoir fluid.

In vertical wells a single fracture job per reservoir is commonly done. In high angle or

horizontal wells, it is common to perform multiple fracturing jobs (multi stage fracturing) along

the path of the bore hole through a reservoir. Fr acturing jobs are often high rate, high volume,

and high pressure pumping operations. They ar e accomplished by bringing very large truckmounted diesel-powered pumps (e.g., 2,000 hp or more ) to the well site to inject the fracturing

fluids and material, and to power the support equipment such as fluid blenders. The measure of

the power required is based on the hydraulic hor sepower necessary to fracture the well. Although

very short in duration (typically less than a day) , fracturing activities may result in substantial

NO

x 

# emissions due to the very high horsepower requirements.

Oil and gas wells are commonly classified as vertical, directional, or horizontal wells,

depending on the direction of the well bore. Vert ical wells are the most common, and are wells

3-4

# 3-5 that are drilled straight down from the location of the drill rig on the surface. Directional wells

are wells where the well bore has not been drilled straight down, but has been made to deviate

from the vertical. Directional we lls are drilled through the use of special tools or techniques to

ensure that the well bore path hits a particular subsurface target, typically located away from (as

opposed to directly under) the su rface location of the well. Hori zontal wells are a subset of

directional wells in that they ar e not drilled straight down, but ar e distinguished from directional

wells in that they typically have well bores th at deviate from vertical by 80 - 90 degrees.

Horizontal wells are commonly dr illed in shale formations. On ce the desired depth has been

reached (the well bore has penetrated the target fo rmation), lateral legs are drilled to provide a

greater length of well bore in the reservoir.

# 4.0 Data Collection Plan

ERG’s Data Collection Plan identified th e proposed approach for collecting the

information needed to develop a comprehensive emissions inventory for land-based drilling rig

engines in the state of Texas in 2008. The primar y focus of the data collection survey was to

obtain engine operating data from rig operators who were activel y drilling in Texas in 2008. The

goal of this survey was to obtain sufficient data to allow for the development of a series of

“model” drilling rig emission profiles for differe nt well types and/or depths to apply to the

corresponding subsets of the TRC well activity data.

Details of the Data Collection Plan were subj ect to external peer review and approved by

TCEQ. ERG conducted the data colle ction as per the approved Da ta Collection Plan, which is

included as Appendix A.

4.1 Participant Recruitment

In order to encourage survey response rates, stakeholder support for the study was

sought. In addition to consulting with contacts at the University of Texas, Southern Methodist

University, and the Texas Railro ad Commission for suggestions on implementing the survey and

soliciting participants, the following trade asso ciations were contacted to help encourage

participation in the study:

• International Association of Drilling Contractors (IADC)

• Texas Independent Producers and Royalty Owners Association (TIPRO)

• Texas Oil and Gas Association (TXOGA)

ERG provided the trade associations with a draft copy of the survey materials and

requested they distribu te them to their membership for feedback. In addition, ERG requested

these trade groups lend their support to the pr oject through a letter of introduction about the

study to be sent to their constituents. While thes e associations were s upportive of the goals and

appreciated the need for this study, ERG did not receive any feedback on the draft survey

materials. However, both TIPRO and TXOGA r ecognized the importance of the project and

agreed to allow ERG to reference their support in the survey transmittal letter (see Appendix B).

4.2 Phone/Email Surveys

Once the survey was developed, ERG obtained contact information for oil and gas well

operators and drilling contractors in order to distribute the surve y. The primary source of data

used to identify target respondents was the commercial RigData ® 

# database. This database

4-1

# 4-2 contains information for over 24,000 drilling pe rmits issued in Texas between January 1, 2008

and March of 2009. For over 14,000 of these records, drilling contractor c ontact information was

provided. The RigData ® 

# database used to develop the target respondent list has been provided to

the TCEQ in electronic format

ERG attempted to contact each of the drilling contractors included in this listing through

phone and/or email surveys. The survey effort itself focused on collecting the following

information from each respondent:

• The number of engines on a rig

• Engine make, model, model year, and size (hp)

• Average load for each engine

• Engine function (draw works, mud pumps, power)

• Actual engine hour data for each well (total hours)

• Actual engine fuel use data for each well (total fuel use)

• Total well drilling time (actual number of drilling days)

• Total well completion time (number of days needed for well completion activities)

• Well depth

• Number of wells represented by survey

An example of the data collection form used to compile the results of the survey is

presented in Appendix C. For those respondents w ho were contacted via email, an Excel file

containing similar information was provided as an email transmittal. The results of the survey

effort are described in Section 5.0.

4.3 Confidentiality

Confidentiality was stressed to survey particip ants, as evidenced in the survey letter. ERG

is particularly sensitive to the privacy of individuals and businesses. Therefore all interviews and

data collection efforts began with a guarantee of privacy, anonymity, a nd confidentiality. To

ensure survey respondent’s rights to privacy, respondents were info rmed of the research purpose,

the kinds of questions that w ould be asked, and how the TCEQ may use the results of the study.

Confidentiality was maintained by eliminating re spondent names from the study datasets before

provision to the TCEQ.

# 5.0 Data Collection Results

5.1 Survey Findings

Using the contact information in the RigData ® 

# dataset, ERG began implementation of the

Data Collection Plan on April 30, 2009 and co llected data through June 16, 2009. Initially,

contacts were attempted with many of the oil a nd gas well operators themselves. As a rule, the

operators were knowledgeable concerning gene ral information about the drilling process

including average depth, drilling days, number of engines used and gallons of fuel used per day.

However, they typically did not have the specific information about the ch aracteristics of the rig

engines (model year, engine size, and load factors) needed to estimate emissions.

During phone interviews it was discovered that several of the operators also drilled their

own wells. Based on these intervie ws, the strategy for the remainder of the data collection phase

of the project was refined. In particular, fact ors such as depth of the well, the engine

configurations used, the individual preferences of drilling superintendents to idle engines or to

turn them off, and the difficulty of estimating load and operating hours ov er the entire drilling

period made it difficult to collect the data via email or fax without bei ng able to discuss the

needed data directly with the re spondent. The complexity of the drilling process a nd the lack of

response from the operators to anything other th an a verbal interview informed the collection

process for the drilling contractors.

Therefore to obtain the information needed, a verbal interview with the actual drilling

contractors was determined to be preferable in order to carefu lly walk the respondent through the

survey questions.

The RigData ® 

# dataset included approximately 225 uni que contact profiles for drilling

contractors. However, many of these contacts were regional contacts for the same company,

several had gone out of business, and others had recently consolidated into a single company. As

a result, the final number of unique contact s for the drillers was approximately 190.

ERG attempted to contact each of the drilli ng companies at least four times, by phone

and/or email. Based on the experience with contacting the operators, verbal contact was

attempted with each respondent before distri bution of the survey through email or fax. The

strategy was designed to increa se participation by explaining the purpose of the survey, to

explain the data being requested, and thus avoid receiving incomplete or inaccurate surveys. For

each targeted survey respondent, three attempts were made via phone to find someone to speak

5-1

# with before a voicemail was left or an email wa s sent. This strategy was intended to eliminate

dead-end contacts such as unret urned voicemails or emails.

Because smaller companies generally had fewer administrative and management

personnel, contact for companies with less than 50 wells generally consisted of a phone call

answered by a receptionist who either took a me ssage, transferred the ca ll to a voicemail, or

established direct contact with someone who coul d answer the survey que stions. If there was no

answer, a return call was schedule d. After three attempts without response, a short voice message

was left. If no reply was received to this messa ge, no further attempt was made to contact the

respondent.

For the larger drilling companies (those thatdrilled over 100 wells in 2008), an enhanced

contact strategy was used. Because some of th e companies are quite large and represent a

significant percentage of the wells drilled in th e state, more extensive efforts were made to

increase their participation. For several of these companies, an effort was made to encourage

response by providing them with ta ilored Excel spreadsheets iden tifying their wells and asking

about specific well types and loca tions. In addition, attempts were made to contact the company

through multiple avenues, either through multip le contacts provided in the RigData ® 

# dataset, or

through contact information available on-line. In one case, ERG collected data from one of the

top 25 drilling contractors after an initial refu sal from one drilling superintendent by requesting

data through other contacts at the company.

Generally speaking, at least ten contacts th rough phone calls and emails were attempted

for the larger companies, the medium sized co mpanies required from 5 to 7 contacts, and the

smaller companies required 3 to 4 contacts before identifying the appropri ate person to talk to.

At the completion of the survey effort, 45 completed surveys with sufficient data to

estimate emissions had been obtained from 39 differ ent drilling rig contract ors and/or oil and gas

well operators. This figure reflects approximately a 15% response rate for complete surveys from

the attempted contacts. One additional survey wa s received after the submittal cutoff date, but it

was not received in time for inco rporation into the inventory.

The surveys that were received and used in the inventory were representative of over

1,500 wells drilled in Texas in 2008 and covered 121 counties and all of the major oil and gas

basins in the state (Andarko, East Texas, Ft. Worth/Bend Arch, Permian, and Western Gulf). An

additional 17 survey responses were obtained, but the respondents for these surveys did not

provide sufficient information to be used in the final model drilli ng rig emission profile

development. Typically, these incomplete respon ses were those received from the oil and gas

5-2

# well operators and not the drilli ng contractors. Considering both the complete and incomplete

survey responses, the overall response rate for the survey effort was approximately 21%.

Table 5-1 presents the summary results for the survey effort.

Table 5.1 Survey Summary Statistics

Survey Activity/Results Number of Respondents

Attempted Company Contacts 295

Refusal to Participate 24

Soft Refusal (did not return attempted contacts via

phone calls or email) 209

Respondent Interviewed and provided sufficient data

for inclusion in inventory dataset 45

Respondent Interviewed, but insufficient data

provided for inclusion in inventory dataset 17



# Figure 5-1 provides a county-leve l map of Texas providing a gr aphical representation of

the geographic coverage of the survey results.

5.2 Model Rig Category Development

Upon completion of the survey and data collec tion task, the survey results were compiled

into a spreadsheet database for evaluation in order to disaggrega te the survey data into subcategories for model drilling rig profile development. As each completed survey was received

from the surveyor, identifying information fo r that survey was entered into a tracking

spreadsheet, and the survey was prepared for da ta entry and forwarded to data entry personnel.

Upon receipt of the survey, data entry personnel tran sferred the data in the survey form into the

spreadsheet database, and updated the survey trac king spreadsheet with date of data entry and

their initials. A QA check was then performed on the data entered into the spreadsheet database,

and the tracking spreadsheet was updated to indi cate the date of QA and the initials of the

personnel performing the QA.

5-3

# Figure 5.1 Counties with Survey Data

Survey results for vertical, directional, a nd horizontal well types were reviewed as

described below.

A review of the 32 surveys completed for vertical drilling, representing 1,261 wells,

provided a clear distinction betw een the engine profiles (number and size of engines) used to

drill shallow vertical wells relative to deeper vertical wells. In part icular, by separating the

5-4

# survey results into those represen ting wells at 7,000 feet of dept h or less, and those representing

wells deeper than 7,000 feet, the fo llowing differences were observed:

• The average drilling duration for the shallo wer wells was 8 days, with a maximum of

14 days;

• The average drilling duration for deeper wells was 27 days, with a maximum of

84 days;

• Only 1 of the 16 profiles for shallow wells was for an electrical rig, compared to

6 electrical rig profile s out of the 16 profiles for the deeper wells;

• The engine sizes were signifi cantly different for the shallow and deep wells, with the

survey results for the shallow wells c ontaining no engines over 700 hp, while the

engine population for surveys received for th e deeper wells contained approximately

25 engines rated at over 1,000 hp.

For horizontal and directional wells, a tota l of 13 completed surveys were received

representative of 288 wells. The average measured well depth of the wells covered under these

surveys was approximately 11,000 feet, with a minimum of 8,000 feet and a maximum of

17,688 feet. All of the profiles for hor izontal and directional wells were either for electrical rigs

(6 profiles) with 2 or 3 engines, or for mechanical rigs (7 profiles) with 6 engines. Due to the

limited number of surveys received for horizon tal and directional we lls, and the relative

consistency of the profiles for these types of wells, it was determ ined to consolidate the survey

results for horizontal and directiona l wells into one model rig category.

Table 5-2 provides a summary of the final survey statistics for each of the three model rig

well type categories.

Table 5.2 Model Rig Category Statistics

Model Rig

Well Type

Category Number

of surveys

included

in profile Number of

respondents

providing

surveys Number of

Wells

Represented Number of

Mechanical

Rig Profiles Number of

Electrical

Rig Profiles

Horizontal and

Directional

Wells 13 10 288 7 6

Vertical Wells

<= 7,000 feet 16 16 900 15 1

Vertical Wells >

7,000 feet 16 13 361 10 6



# Tables D-1 through D-3 in Appendix D contain the collected survey data for each of the

three model rig well type categories.

5-5

# 5.3 Fracturing

During the data collection phase of this project, information was solicited from

respondents regarding fractur ing activities. While not specifically mentioned in the original work

plan or data collection plan, a re view of existing literature and studies showed fracturing activity

to be increasing in Texas over the past several year s. As part of their survey response, the drilling

contractors and oil and gas exploration compan ies occasionally provided some qualitative or

quantitative information regarding fracturing, but the responses were highly variable in content

and format. In general, the indication was that fr acturing was a short-term activity (less than one

day in duration), and that pump trucks containi ng multiple, large diesel-fired engines could be

used simultaneously to pump the fracturing fluids into the well. Specific information regarding

the frequency of fracturing events and the total hp-hours required per event were not

generalizable to the invent ory as a whole, however.

Further investigation regardi ng fracturing was made by contacting service companies that

provide fracturing services, as well as interviewing personnel at the TRC and researching the

availability of fracturing data on-line through the TRC website.

Two of the three service comp anies contacted provided some data for the fracturing

activities they performed in 2008, which varied from the use of five 1,250 hp pump engines for a

total duration of 1 hour, to the use of seven 2,500 hp pump engines for a total duration of

12 hours. The third service compa ny contacted did not provide any data as of the time of this

draft report.

Unlike the drilling permit records obtained through the “Drilli ng Permit Master and

Trailer” database, fracturing data is not compiled by the TRC or otherwise made readily

available in any summarized format through any on-line queries or electronic datasets. However,

images of individual well completion records (re ferred to as G-1 forms for gas well completions

and W-2 forms for oil well completions) are av ailable on-line through the TRC website. Using

American Petroleum Institute (API) numbers fr om the TRC data, a random on-line search was

performed to review the G-1 and W-2 record s for approximately 1,200 wells. The G-1 and W-2

forms were only found for approximately one-thir d of these wells. These forms are frequently

completed by hand, with inconsistent data be ing reported by individua l well operators, with

much of the data being incomplete. However, base d on a review of the records we were able to

identify, it appears that approxi mately 80% of the wells in the sample had some kind of

fracturing activity occurri ng prior to well completion.

5-6

# 5-7 While data is not currently available under this project to provide em ission estimates for

fracturing activities, due to the large engine sizes used by the pump trucks, this is a source

category that may be considered for inclusion in future emission inventor y development projects.

# 6.0 Emissions Inventory Development and Results

The 2008 activity data from the TRC and the model rig emissions profiles developed

using the survey results for each model rig well ty pe category were utilized to develop emissions

estimates for selected target years as described below.

6.1 Activity Data

6.1.1 2008 Base Year Activity

Activity data for the 2008 base year was obtained from the TRC through acquisition of

the “Drilling Permit Master and Trailer” databa se, which contains information on well drilling

activities, including American Petroleum Ins titute (API) number, date approved, location

(county), well profile (vertical, horizontal, directional), well depth, spud-in date, and well

completion date. The TRC data was combined with data from the RigData ® 

# dataset used to

identify survey respondents as discussed previo usly. This combined database was used to

compile an initial list of all oil and gas wells that were either completed in 2008 (based on

completion date), or that were started in 2008 (based on spud-in date).

As many of the wells comple ted in 2008 were started in 2007, and many of the wells

started in 2008 were not completed until 2009, an ad justment was needed to the initial list of

wells to determine a representative dataset for 2008. This adjustment was accomplished by

including only those wells w ith spud dates of December 1, 2007 or later (and that were

completed in 2008), and only those wells with co mpletion dates of Janu ary 31, 2009 or earlier

(and that had spud-in dates in 2008). In all, 16,964 oil and gas wells are included in the final

2008 dataset which compares favorably with th e 16,569 oil and gas well completions reported by

the TRC in 2008 (TRC, 2009c). The slight discrepa ncy with the total well s included in the 2008

dataset compared to the completion figure from the TRC is due to the fact that the TRC data only

includes 2008 completions and does not account for wells started in 2008 that were not

completed until 2009.

The final 2008 activity dataset contains drilling activity da ta for 210 of the 254 counties

in Texas.

6.1.2 2002 and 2005 Prior Years Activity

Once the final 2008 activity data set was established, activity data scaling factors for 2002

and 2005 were developed based on the ratio of the oil and gas well completions for those years

relative to the number of oil and gas well comp letions in 2008 as reported by the TRC (TRC

6-1

# 2009a, TRC 2009b, TRC 2009c). This analysis was perf ormed at the TRC district level, which

allowed geographic variation in drilling trends across the state from 2002 through 2008 to be

reflected in the 2002 and 2005 prior year datase ts. Figure 6-1 provides a county-level map of

Texas showing the location and covera ge of each of the TRC districts.

Figure 6.1 TRC District Map

6-2

# For example, in 2008 there were 512 total oil/ga s well completions in TRC District 1, and

in 2002 there were 165 total oil/gas well completions in District 1. Therefore, the scaling factor

from 2002 to 2008 is:

2002 to 2008 scaling factor = 165 wells / 512 wells = 0.32

Table 6-1 shows the 2002, 2005, and 2008 oil an d gas well completion records and the

resultant 2002 and 2005 scaling factors that were developed for each district for this analysis.

Table 6.1 2002 and 2005 Prior Year Activity Scaling Factors

TRC District 2008 Total

Oil/Gas

Completions 2002 Total

Oil/Gas

Completions 2002 Scaling

Factor 2005 Total

Oil/Gas

Completions 2005 Scaling

Factor

1 512 165 0.32 389 0.76

2 687 513 0.75 672 0.98

3 699 724 1.04 712 1.02

4 1,351 1,266 0.94 1,123 0.83

5 738 618 0.84 714 0.97

6 1,973 717 0.36 1,556 0.79

7B 746 298 0.40 501 0.67

7C 2,082 887 0.43 1,389 0.67

8 2,641 1,281 0.49 927 0.35

8A 559 756 1.35 626 1.12

9 3,484 1,096 0.31 1,185 0.34

10 1,095 419 0.38 856 0.78



# As can be seen in Table 6-1, certain areas of the state experienced significant growth in

drilling activity in 2008 relative to 2002, while other areas remained relatively stable. The most

dramatic example of this change in activity can be seen in T RC District 9, whic h contains the

Barnett Shale, an area that has experienced sign ificant growth in drilling activity over the last

6 years. For this District, drilling activ ity approximately tripled between 2002 and 2008.

The scaling factors presented in Table 6-1 we re applied to the 2008 base year well depth

totals by county for each of th e three model rig well types to determine county-level well depth

for each model rig type for 2002 and 2005.

6.1.3 2009 through 2021 Projected Activity

2009 through 2021 projected activity data we re developed using the 2008 base year

activity data from the TRC and forecasting futu re activity based on US DOE Energy Information

Administration (EIA) projections of oil and gas production for the Southwest and Gulf Coast

6-3

# 6-4 regions from the Annual Energy Outlook 2009, Updated Reference Case with ARRA (EIA,

2009). The EIA data tables (specifically Tables 113 and 114) present estimated crude oil and

natural gas production estimates for the years 2006-2030. The geographic le vel of the projected

data is by EIA Region.

Portions of Texas fall into three EIA Regions : Gulf Coast (Region 2); Southwest (Region

4); and Midcontinent (Region 3). The majority of the State is in the Gulf Coast and Southwest

EIA Regions. Only a small portion (area to the west of Oklahoma) is in the Midcontinent

Region. In addition, because the Midcontinent EIA Region contains six other states, any

projections data for the Midcont inent EIA Region may not be reflective of Texas operations.

Thus, it was assumed that the Southwest and Gulf Coast EIA Regions are representative of Texas

and each region was weighted equally to determ ine the statewide projections. Figure 6-2 shows

the EIA regions and their coverage in Texas.

Figure 6.2 EIA Regions

Tables 6-2 and 6-3 show projected crude oil and natural gas production for the Gulf

Coast and Southwest EIA Regions, as well as the combined total for both regions, from 2008

through 2021. The total percentage change for each year from 2009 through 2021 is presented

relative to the base year of 2008.

This data was then used to calculate a proj ected growth factor (%) for each year from

2009 through 2021 by weighing the oil and gas percen tage growth figures relative to the number

of oil and gas wells completed in Texas 2008. For example, the projected growth factor for 2009

is calculated as follows:Table 6.2 Projected Crude Oil Production 2008-2021Crude Oil Production (MMBBL/day)EIA Region20082009201020112012210320142015201620172018201920202021Gulf Coast0.5030.5050.5030.4830.4650.4500.4380.4010.3740.3470.3200.2940.2710.251Southwest0.9190.9200.9040.8920.8900.9150.9561.0001.0431.0821.1171.1471.1671.183Total1.4221.4251.4071.3751.3551.3651.3931.4021.4161.4291.4361.4421.4381.434% change from 20080.21%-1.05%-3.29%-4.71%-4.01%-2.02%-1.42%-0.39%0.50%1.02%1.38%1.14%0.86%Table 6.3 Projected Natural Gas Production 2008-2021Natural Gas Production (trillion cubic feet)EIA Region20082009201020112012210320142015201620172018201920202021Gulf Coast5.4125.1654.7924.6064.4154.3264.2334.1624.0864.0203.9593.9213.9033.825Southwest2.1702.4742.6232.7162.7132.6792.6592.6452.6272.6092.6032.5912.5912.564Total7.5827.6397.4157.3217.1287.0056.8926.8076.7136.6296.5636.5126.4956.388% change from 20080.76%-2.20%-3.44%-5.99%-7.61%-9.09%-10.2%-11.5%-12.6%-13.4%-14.1%-14.3%-15.7%6-5

# 2009 growth factor = ((% change from 2008 to 2009 in Crude Oil Production x number of oil

well completions in 2008) + (% change from 2008 to 2009 in Natural Gas

Production x number of gas well comple tions in 2008)) / (total number of

oil and gas well completions in 2008)

Using the data in Tables 6-2 through 6-4, the projected growth factor for 2009 is:

2009 growth factor = ((0.21% x 6,208) + (0.76% x 10,361)) / (6,208 + 10,361) = 0.55%

Table 6-4 shows the growth factors that were developed for each projected year as a

result of this analysis. These f actors were then applied to the 2008 base year well depth totals by

county for each of the three m odel rig profile well types to determine activity data for 2009

through 2021. It is worth noting that through the first five months of 2009, the number of well

completions in Texas has exceeded the number of well completions for the same period in 2008.

However, during the second half of 2008, there was a dramatic incr ease in drilling activity in

Texas which dropped off significantly by the end of the year due to commodity prices and the

effects of the economic recession. Therefore, while Table 6-4 presents projected production data

based on the current DOE EIA da ta, the volatility in drilling activity during 2008, coupled with

the rapidly changing economic climate over the last year, results in a high level of uncertainty

regarding these (or any) projec tions for drilling activity in 2009 and beyond. These projections

are based on the best data currently available, but should be revisited once the economic climate

and oil and gas prices stabilize in order to more accurately assess fu ture year projected

emissions.

6.1.4 2002, 2005, and 2008 through 2021 Activity Summary

Once the final activity dataset for 2008 was de termined, total county-level well depth for

each of the three model rig well type categorie s was calculated by summing the individual well

depths in each county by mode l rig well type category. The tota l county-level well depth for

2002, 2005, and 2009 through 2021 for each model rig we ll type category was then calculated

based on the 2008 summary data using the met hodology described above. Table 6-5 shows the

total depth by model rig well type category for 2008 (blank cells indicate there was no activity in

that county for that well type).

6-6Table 6-4 Projected Growth Factors 2009-2021Production % change from 20082008 Well Completions2009201020112012210320142015201620172018201920202021Oil6,2080.21%-1.05%-3.29%-4.71%-4.01%-2.02%-1.42%-0.39%0.50%1.02%1.38%1.14%0.86%Natural Gas10,3610.76%-2.20%-3.44%-5.99%-7.61%-9.09%-10.2%-11.5%-12.6%-13.4%-14.1%-14.3%-15.7%Projected Growth Factor0.55%-1.77%-3.38%-5.51%-6.26%-6.44%-6.92%-7.31%-7.67%-8.02%-8.31%-8.54%-9.52%6-7

# Table 6.5 2008 Total Depth by Model Rig Well Type Category (1,000 feet)

County Vertical <= 7,000 feet Vertical > 7,000 feet Directional/Horizontal

Anderson 52.20 113.70 20.33

Andrews 1,969.19 1,115.41 46.30

Angelina 1.32 394.74 101.70

Aransas 6.00 45.45 23.30

Archer 221.32 15.50

Atascosa 39.80 38.50

Austin 67.19 28.70 15.02

Bastrop 6.40 74.60 71.70

Baylor 45.54 5.50

Bee 239.20 204.49 240.25

Bell 4.50

Bexar 0.80

Borden 11.45 166.10 42.85

Bosque 10.00 15.80

Bowie 9.00

Brazoria 15.90 252.90 103.39

Brazos 33.14 214.89

Briscoe 6.50 8.50

Brooks 17.16 582.32 103.96

Brown 41.00

Burleson 208.41 172.77

Caldwell 29.86 8.15

Calhoun 15.60 112.60 82.83

Callahan 81.68

Cameron 9.50

Carson 6.50 10.10

Cass 7.00

Chambers 78.60 153.46

Cherokee 9.40 886.08 243.05

Childress 9.30

Clay 116.15 23.00 52.50

Cochran 229.30 25.00

Coke 121.70 15.70

Coleman 97.69

Colorado 122.71 149.88 25.42

Comanche 3.00

Concho 167.15

Cooke 161.00 228.84 17.90

Coryell 4.00

Cottle 39.20 106.70 8.00

Crane 602.54 175.75 43.26

Crockett 881.48 1,822.74 131.17

Crosby 91.69

Culberson 216.89 44.00

Dallas 99.50



# 6-8

# Table 6.5 2008 Total Depth by Model Rig Well Type Cate gory (1,000 feet) (Cont.)

County Vertical <= 7,000 feet Vertical > 7,000 feet Directional/Horizontal

Dawson 42.70 359.69 17.50

Denton 11.10 79.50 2,491.72

DeWitt 57.40 392.08 568.84

Dickens 174.02 123.70

Dimmit 270.51 178.14 125.64

Duval 68.80 479.83 71.95

Eastland 48.09

Ector 501.36 1,619.73 73.30

Edwards 119.55 206.10 67.50

Ellis 1.50 269.00

Erath 29.95 97.10

Falls 1.80

Fannin 19.00

Fayette 15.08 22.10 93.80

Fisher 162.58 68.30

Foard 25.10

Fort Bend 159.90 74.65 125.04

Franklin 10.90 94.55

Freestone 11.40 2,650.39 484.37

Frio 153.73 62.80 61.74

Gaines 407.24 633.81 56.99

Galveston 4.40 51.15 53.37

Garza 189.30 52.00 3.20

Glasscock 900.20 19.20

Goliad 231.61 377.49 76.04

Gonzales 15.53 21.26 21.50

Gray 12.15 13.00

Grayson 12.99 49.00 37.60

Gregg 503.10 263.25

Grimes 3.90 169.64

Guadalupe 9.20 7.79

Hale 65.00 15.00

Hansford 62.41 263.33 50.20

Hardeman 12.59 96.23 28.60

Hardin 81.95 284.12 180.35

Harris 19.20 34.20 85.40

Harrison 60.61 2,900.41 1,836.28

Hartley 17.95

Haskell 63.70

Hemphill 6.50 3,936.45 685.47

Henderson 233.25 53.60

Hidalgo 37.54 1,324.96 347.92

Hill 7.00 1,161.12

Hockley 208.43 123.40 87.44

Hood 1,011.19



# 6-9

# Table 6.5 2008 Total Depth by Model Rig Well Type Cate gory (1,000 feet) (Cont.)

County Vertical <= 7,000 feet Vertical > 7,000 feet Directional/Horizontal

Hopkins 4.50 21.80

Houston 8.30 161.85 56.50

Howard 81.64 779.85

Hudspeth 26.00 22.00

Hutchinson 313.77 17.10 39.00

Irion 196.70 1,513.07

Jack 197.69 137.50

Jackson 205.63 319.66 32.99

Jasper 8.10 44.50 194.33

Jefferson 24.80 166.30 300.61

Jim Hogg 9.40 194.13 14.38

Jim Wells 84.07 52.75 6.11

Johnson 52.00 8,421.16

Jones 221.93

Karnes 21.40 100.90 179.60

Kenedy 7.00 382.44 92.50

Kent 120.99 109.80 36.00

King 203.90 7.40

Kleberg 54.50 150.10

Knox 54.20 7.20

La Salle 52.36 691.44 24.00

Lamb 32.80 7.50

Lavaca 107.69 552.74 216.53

Lee 35.30 24.48 83.01

Leon 68.91 524.00 310.50

Liberty 34.00 330.85 145.10

Limestone 6.30 1,876.14 451.40

Lipscomb 214.88 1,447.13

Live Oak 132.03 342.83 129.60

Loving 149.10 620.83 33.00

Lubbock 60.30

Lynn 46.25

Madison 36.31 66.20

Marion 104.73 66.50

Martin 3,643.04

Matagorda 25.97 590.09 100.27

Maverick 333.88 27.00 241.35

McCulloch 1.00

McLennan 1.23 9.50 9.50

McMullen 128.79 749.60 49.50

Medina 30.11

Menard 70.50

Midland 8.60 2,637.28 75.30

Milam 19.29 10.00

Mitchell 640.83



# 6-10

# Table 6.5 2008 Total Depth by Model Rig Well Type Cate gory (1,000 feet) (Cont.)

County Vertical <= 7,000 feet Vertical > 7,000 feet Directional/Horizontal

Montague 107.08 475.44 365.20

Montgomery 6.00 51.95 24.52

Moore 126.48 6.30

Motley 5.00 9.00

Nacogdoches 1.00 2,210.41 761.92

Navarro 36.15 102.10 6.60

Newton 30.55 68.50

Nolan 332.89 37.70

Nueces 66.84 339.36 64.62

Ochiltree 16.50 309.88 427.67

Oldham 45.90

Orange 7.00 17.00 101.32

Palo Pinto 212.17 135.05

Panola 92.08 2,693.70 1,652.45

Parker 6.45 880.85

Pecos 224.68 2,667.60 840.55

Polk 60.63 90.83 218.65

Potter 21.20

Reagan 34.05 2,509.42

Real 3.00

Red River 5.80 8.20 5.80

Reeves 88.15 310.70 374.12

Refugio 588.28 335.65

Roberts 17.80 1,337.30 361.71

Robertson 2,317.69 438.50

Runnels 375.57 4.80

Rusk 27.00 3,697.44 508.05

Sabine 8.00

San Augustine 52.50 286.91

San Jacinto 3.70 127.95 24.00

San Patricio 29.80 94.07 89.11

Schleicher 117.95 416.02

Scurry 155.28 224.80 96.96

Shackelford 206.38

Shelby 546.60 881.58

Sherman 274.40 80.60

Smith 6.50 108.75 185.85

Somervell 144.00

Starr 69.53 1,406.17 178.30

Stephens 469.77 14.40

Sterling 40.42 294.86 9.25

Stonewall 221.08

Sutton 740.80 1,866.84 7.20

Tarrant 37.45 18.00 7,630.70

Taylor 69.30 4.00



# 6-11

# Table 6.5 2008 Total Depth by Model Rig Well Type Cate gory (1,000 feet) (Cont.)

County Vertical <= 7,000 feet Vertical > 7,000 feet Directional/Horizontal

Terrell 79.85 295.70 92.95

Terry 26.89 86.20 55.20

Throckmorton 90.84

Titus 4.60

Tom Green 123.60 16.00

Trinity 4.10

Tyler 23.11 70.20 329.95

Upshur 11.77 260.21 96.80

Upton 78.50 4,699.94 288.60

Val Verde 3.10 73.30

Van Zandt 8.20 35.20

Victoria 296.15 207.20 33.03

Walker 4.90

Waller 82.71 61.80 10.00

Ward 460.51 161.91 482.33

Washington 6.00 42.00

Webb 262.53 1,689.96 305.77

Wharton 239.83 586.42 114.77

Wheeler 3,839.70 482.40

Wichita 366.76 9.00

Wilbarger 126.99

Willacy 301.75 25.50

Wilson 4.45

Winkler 20.50 294.95 148.92

Wise 93.50 121.00 2,032.78

Wood 17.70 37.86 32.00

Yoakum 462.25 195.22 171.10

Young 259.30

Zapata 6.00 2,031.18 500.35

Zavala 16.05 60.20

Statewide Total 20,746 82,337 48,121



# Appendix E contains a summary of the total well depth by county and year for each

model rig well type category.

6.2 Model Rig Emission Profiles

6.2.1 Model Rig Engine Profiles

As described in Section 5.2, the survey data was disaggregated in to three model rig

categories for the following well types and depths based on the results of the data collection

survey:

• Vertical wells less than or equal to 7,000 feet;

6-12

# • Vertical wells greater than 7,000 feet; and

• Horizontal/Directional wells.

For each of these rig categories, a model rig engine profile was developed. In order for

the model rig engine profile data to be applied consistently to the TRC activity data, the survey

results were normalized to a 1,000 foot drilli ng depth. This was accomplished by dividing the

total drilling hours for each engine included in each surv ey by the well depth for that survey to

obtain the hours of operati on per engine per 1,000 f eet of drilling depth.

As the engine profiles and functions for engi nes used on mechanical rigs and electrical

rigs are distinctly different as described in Section 3.3, separate engine profiles for mechanical

and electrical rigs were developed fo r each model rig well type category.

The following average engine parameters were calculated for each model rig well type

category using a weighted average for each parameter based on the number of wells associated

with each survey:

• Number of engines by rig type (i.e., m echanical draw works, mud pumps, and

generators; electrical rig engi nes; and completion engines).

• Engine age

• Engine size (hp)

• Engine on-time (hours/1,000 feet drilled)

• Overall average load (%)

Surveys with missing data parameters were excluded from the weighted average

calculation. The weighted averaged engine parameters developed for each model rig category by

rig type are summarized in Table 6-6.

6-13

# Table 6.6 Model Rig Engine Parameters

Model Rig

Category Rig Type Engine

Type # of

Engines Average

Age (yrs) Engine

Size (hp) Hours/1,000

ft drilled Average

Load (%)

Draw Works 1.60 7 442 30.8 51.8

Mud Pumps 1.69 6 428 29.4 45.9 Vertical <=

7,000 ft 1 

# Mechanical

Generator 0.97 4 330 28.3 70.4

Draw Works 2.01 25 455 35.9 47.4

Mud Pumps 1.62 18 761 33.2 46.0 Mechanical

Generator 2.00 10 407 19.3 78.7 Vertical

> 7,000 ft

Electrical 2.15 2 1,381 62.6 48.5

Draw Works 2.00 15 483 50.1 41.1

Mud Pumps 2.00 6 1,075 36.4 42.6 Mechanical

Generator 2.00 10 390 26.8 69.0 Horizontal/

Directional

Electrical 2.03 2 1,346 47.3 52.5

All All Completion 1.00 Default 350 10.0 43.0

1 

# The one electrical rig surveyed for ver tical wells <= 7,000 feet represents less than 0.5% of the total wells in this

model rig well type category and was considered to have a negligible contribution to the emissions profile.



# As can be seen in Table 6-6, the expected trend toward larger engine sizes and more

hours required per 1,000 feet for th e deeper vertical wells and the horizontal/directional wells is

verified. The older engine ages for the mechanical rigs used on the deeper vertical wells and the

horizontal/directional wells are based on severa l surveys received for these well types that

covered a large number of wells drilled by rigs with older engines. However, as noted in Section

3.3, the future trend for these types of wells is towards the use of electrical rigs, and the average

age of the engines used on th e electrical rigs for these we ll types is only two years.

6.2.2 Model Rig Emission Factors

Once the final mechanical and electrical rig engine profiles were established for each

model rig well type category, US EPA’s NONR OAD model was used to develop criteria

pollutant emission factors for each rig type for each year of the inventory (2002, 2005, and

2008 – 2021). Use of the NONROAD model allowed for expected reductions in emissions over

time due to the phasing in of EPA’s emissions standards for nonroad diesel engines.

Using the engine parameters summarized in Table 6-6, NONROAD model input files

were developed (U.S. EPA, 2005). In particul ar, the NONROAD Activity file was modified

using the hours per 1,000 feet dri lled and average load, while the Population files were modified

using the engine size. In additi on, the population for a particular engine type was adjusted to a

unit value of 1 for ease in calculation. The modi fied NONROAD files used in the emission factor

calculation have been provided to the TCEQ in electronic format.

6-14

# A total of 16 years were modeled – the base year of 2008, the prior years of 2002 and

2005, and 13 projected years from 2009 to 2021. Fo r each year modeled, the engine model age

was kept constant. For instance, th e 7 year old mechanical draw wo rks engine for vertical wells <

7,000 feet was modeled as a 2001 model year engi ne for the 2008 base year, as a 1995 model

year engine for 2002, and as a 2014 model y ear engine for the future year of 2021.

The model year-specific emissions output fr om the NONROAD model (i.e., based on the

model year fraction of the unit engine popul ation specified by the NONROAD population file)

was then ratioed up to the number of engines in each rig type. 2 

# For mechanical rigs, the draw

works, mud pump, and generator engine emi ssions were aggregated together. For both

mechanical and electrical rig types, a singl e completion engine of 350 hp running 10 hours per

1,000 feet drilled was also included to model completion activities. A composite model rig

emissions profile was developed by aggregating th e mechanical and electrical rig types together

based upon the percentage of wells associated with each rig type. For example, for the

horizontal/directional model rig well type, a pproximately two-thirds of the wells were

represented by electrical rigs, so the resultant emission factors are weighted two-thirds by the

NONROAD electrical rig emission factors, and one-third by the m echanical rig emission factors.

SO 2 

# emissions are based on fuel sulfur content profiles for Texas obtained from historical

fuel sampling data performed for the TCEQ. The average diesel sulfur content (% weight) for a

particular analysis year was de veloped using the county-level fuel parameter data contained in

TCEQ’s TexN model, weighted by the number of wells in each county. The statewide average

diesel sulfur content values calculated were 0.2995% for 2002 and 2005, 0.0316% for 2008 and

2009, and 0.0015% for 2010 through 2021, reflecting the reduced sulfur requirements over time.

Total hydrocarbon (THC) exhaust emissions fr om the NONROAD model were converted

to VOC and TOG using ratios of 1.053 and 1.070, respectively (U.S. EPA, 2005a). Crankcase

THC emissions were assumed to be equivalent to both VOC and TOG (U.S. EPA, 2005b). For

diesel nonroad engines, PM 10 

# is assumed to be equivalent to PM, while the PM 2.5 

# fraction of

PM 10 

# is estimated to be 0.97 (U.S. EPA, 2005a).

Hazardous air pollutant (HAP) emission f actors were then developed by applying

speciated HAP emissions profiles for PM 10 

# and TOG from the Califor nia Air Resources Board’s

2 

# The NONROAD model allocates the total equipment popula tion across a distribution of model years and estimates

the emissions associated with each model year. For a given calendar year this analysis is interested in just one

engine age/model year representing the average age for eac h model profile. Therefore the emissions for the model

year of interest were scaled back up as if the entire e ngine population specified in NONROAD were allocated to just

this one model year.



# 6-15

# (CARB) Speciation Profile Database for diesel combustion to the PM and TOG emissions

factors obtained from the NONROAD model (ARB, 2001). ARB profile #425 was used to

speciate PM 10 

# , and ARB profile #818 was used to speciat e TOG. Tables 6-7 and 6-8 present the

speciation profiles for PM 10 

# and TOG, respectively.

Table 6.7 PM 10 

# Speciation Factors

HAP HAP CAS # Weight

Fraction of

PM10

Antimony 7440360 0.000036

Arsenic 7440382 0.000005

Cadmium 7440439 0.000040

Cobalt 7440484 0.000011

Chlorine 7782505 0.000344

Lead 7439921 0.000042

Manganese 7439965 0.000040

Nickel 7440020 0.000019

Mercury 7439976 0.000030

Phosphorous 7723140 0.000127

Selenium 7782492 0.000010



# Table 6.8 TOG Speciation Factors

HAP HAP CAS # Weight

Fraction of

TOG

1,3-butadiene 106990 0.002

2,2,4-trimethylpentane 540841 0.003

Acetaldehyde 75070 0.074

Benzene 71432 0.02

Cumene 98828 2E-04

Ethylbenzene 100414 0.003

Formaldehyde 50000 0.147

Methanol 67561 3E-04

m-xylene 108383 0.006

Naphthalene 91203 9E-04

n-hexane 110543 0.002

o-xylene 95476 0.003

Propionaldehyde 123386 0.01

p-xylene 106423 0.001

Styrene 100425 6E-04

Toluene 108883 0.015



# The final emissions profile for each of the three model rig well type categories was

developed by weighing the emission profiles for each rig type (mechanical and electrical) by the

6-16

# percentage of wells of each rig type in each m odel rig well type category. Appendix F presents

the emission factors developed for each of the model rig well type categories for 2002, 2005, and

2008 through 2021.

6.3 Emission Estimation Methodology

Using the model rig well type category emi ssion profiles, county-level emission estimates

were calculated using the activity data from the TRC dataset. C ounty-level well activity data in

terms of total depth (1,000 feet ) drilled was obtained by summing the depth of each individual

well drilled for each of the thre e model rig well type categories for each county as described in

Section 6.1. Once the total depth drilled by mode l rig well type category was known and the

emission factor profile for each model rig well type category was developed, annual county level

emissions for each model rig well type category were estimated by multiplying the total depth

drilled (in terms of 1,000 feet) by the emission factors obtained th rough use of the survey data

and the NONROAD model as follows:

E poll-type 

# = (Depth (1,000 feet/yr)) x (EF poll 

# (tons/1,000 feet))

Where:

E poll-type 

# = Emissions of pollutant for county by model rig well type

category (tons/yr)

Depth = Total depth drilled in m odel rig well type category by county

(1,000 feet/yr)

EF poll 

# = Emission factor of pollutant (tons /1,000 feet)

For 2008 through 2021, NO

x 

# emission estimates for the 110 counties subject to the Texas

Low Emission Diesel (TxLED) program were ad justed downward by 6.2% to account for the

effect of the rule. 3 

# Table 6-9 identifies the counties where this adjustment was made.

Table 6.9 TxLED Counties

Anderson Denton Johnson Robertson

Angelina Ellis Karnes Rockwall

Aransas Falls Kaufman Rusk

Atascosa Fannin Lamar Sabine

Austin Fayette Lavaca San Jacinto

Bastrop Franklin Lee San Patricio

Bee Freestone Leon San Augustine

3 

# The TxLED program requirements initiated in February 200 6, so these adjustments were not applied to the 2002

and 2005 modeling scenarios.



# 6-17

# Table 6.9 TxLED Counties (Cont.)

Bell Fort Bend Liberty Shelby

Bexar Galveston Limestone Smith

Bosque Goliad Live Oak Somervell

Bowie Gonzales Madison Tarrant

Brazoria Grayson Marion Titus

Brazos Gregg Matagorda Travis

Burleson Grimes McLennan Trinity

Caldwell Guadalupe Milam Tyler

Calhoun Hardin Montgomery Upshur

Camp Harris Morris Van Zandt

Cass Harrison Nacogdoches Victoria

Chambers Hays Navarro Walker

Cherokee Henderson Newton Waller

Collin Hill Nueces Washington

Colorado Hood Orange Wharton

Comal Hopkins Panola Williamson

Cooke Houston Parker Wilson

Coryell Hunt Polk Wise

Dallas Jackson Rains

De Witt Jasper Red River

Delta Jefferson Refugio

For counties subject to TxLED requirements, NO

x 

# emissions were estimated as follows:

E NOx-type 

# = (Depth (1,000 feet/yr)) x (EF NOx 

# (tons/1,000 feet)) x (0.938)

Where:

E NOx-type 

# = Emissions of NO

x 

# for each county by model rig well type

category (tons/yr)

Depth = Total depth drilled in m odel rig well type category by county

(1,000 feet/yr)

EF NOx 

# = NO

x 

# emission factor (tons/1,000 feet)

(0.938) = Adjustment Factor to account for 6.2% TxLED reduction

Total county level annual emissions were then obtained by summing the total emissions

for each of the three model rig well type categ ories for each county. Ozone season daily (OSD)

emissions were calculated by dividing the annual emissions by 365 (days/year).

6-18

# 6.4 Results

6.4.1 Emission Summary

Table 6-10 summarizes the statewide annual criteria pollutant emission estimates for

2002, 2005, and 2008 through 2021. Table 6-11 summar izes both annual and OSD criteria

pollutant emissions by county for the 2008 base year. Appendix G contains detailed tables

showing statewide annual emission estimates for each year for all crite ria pollutants and HAPs

(Appendix G, Table 1), as well as county-level annual and OSD emission estimates for each year

for all criteria pollutants and HAPs (Appendix G, Tables 2 and 3, respecti vely). The decreasing

emissions after 2009 reflecting the falling oil and gas production projections from the EIA

dataset for the areas including Texas.

As compared to the previous oil and ga s study prepared by TCEQ in 2007 (for a 2005

base year), the emission estimates presented in this study reflect a signi ficant decrease in the

statewide NO

x 

# emission estimate from drilling rig engine s for 2005 (42,854 tons per year in this

study compared to 119,647 tons per year in the 2007 study). While not as pronounced, there

were also significant decreases in the SO 2 

# and CO emission estimates based on this study. For

VOC, PM 10 

# , and PM 2.5 

# , the estimates contained in this study show slightly higher estimates than

in the previous study. These differences in th e estimates between the two studies can be

attributed to the emissions estimation methodol ogies used in each study. While the previous

study was done using a top-down approach, cons ervative emission estimation assumptions, and

the use of AP-42 emission factors, the current study used 2008 survey data on the actual engine

parameters (engine size, hours of operation, and engine load) used in drilling oil and gas wells in

2008, as well as utilizing the NONROAD m odel to develop emission factors.

6.4.2 NIF 3.0 Files

Once the emissions inventory was complete d, NIF 3.0 area source text-formatted input

files were prepared for base years 2002, 2005, and 2008. The NIF 3.0 files were created using

information provided by TCEQ regarding the correct format and valid code listings for submittal

to TexAER (TCEQ 2009a). Prior to submittal to TCEQ, the NIF 3.0 files were pre-processed

using EPA’s NIF Basic Format and Content Checke r to check for errors and inconsistencies.

Additionally, ERG performed a test upload to TexAER to ensure the files were complete and

accurate and in a format consistent with th e TexAER area source file data requirements.

6-19

# 6-20 Table 6.10 Texas Drilling Rig Estimates (tons/year)

Year CO NOx PM 10 

# PM 2.5 

# SO 2 

# VOC

2002 13,305 35,828 2,552 2,475 4,776 3,631

2005 15,878 42,854 3,036 2,945 5,977 4,337

2008 16,721 55,238 2,543 2,467 956 4,326

2009 16,769 55,457 2,550 2,474 961 4,340

2010 16,336 53,123 2,417 2,344 45 4,182

2011 15,117 48,462 2,319 2,249 44 3,806

2012 14,748 46,253 2,263 2,196 43 3,665

2013 12,008 39,793 1,378 1,337 38 3,413

2014 11,945 39,461 1,372 1,331 38 3,392

2015 11,755 38,837 1,350 1,310 37 3,349

2016 11,558 36,440 1,320 1,280 37 3,320

2017 8,915 34,771 1,118 1,085 36 2,800

2018 6,114 31,282 811 787 35 2,227

2019 6,073 31,127 805 781 35 2,215

2020 6,035 30,771 800 776 35 2,205

2021 3,299 26,063 448 435 33 1,504Table 6.11 2008 Annual and OSD County-LevelCriteria Pollutant Emission EstimatesCO-ANNCO-OSDNOXANNNOX-OSDPM10-ANNPM10-OSDPM2.5-ANNPM2.5-OSDSO2-ANNSO2-OSDVOC-ANNVOC-OSDCountytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/dayAnderson2.03E+015.53E-025.94E+011.62E-013.10E+008.47E-033.01E+008.21E-031.04E+002.83E-035.11E+001.40E-02Andrews2.33E+026.36E-017.75E+022.12E+003.52E+019.61E-023.41E+019.33E-021.37E+013.74E-025.64E+011.54E-01Angelina6.70E+011.83E-011.93E+025.27E-011.03E+012.82E-021.00E+012.73E-023.26E+008.91E-031.72E+014.71E-02Aransas8.80E+002.41E-022.75E+017.51E-021.34E+003.67E-031.30E+003.56E-034.85E-011.32E-032.28E+006.23E-03Archer9.32E+002.55E-023.94E+011.08E-011.35E+003.68E-031.31E+003.57E-038.11E-012.22E-032.05E+005.61E-03Atascosa7.02E+001.92E-022.05E+015.61E-021.07E+002.93E-031.04E+002.84E-033.69E-011.01E-031.72E+004.71E-03Austin7.59E+002.07E-022.63E+017.20E-021.13E+003.10E-031.10E+003.01E-035.13E-011.40E-031.87E+005.10E-03Bastrop1.69E+014.63E-025.76E+011.57E-012.56E+007.01E-032.49E+006.80E-031.04E+002.85E-034.46E+001.22E-02Baylor1.87E+005.10E-039.04E+002.47E-022.65E-017.24E-042.57E-017.02E-041.90E-015.19E-044.23E-011.16E-03Bee5.68E+011.55E-012.06E+025.62E-018.51E+002.32E-028.25E+002.25E-023.92E+001.07E-021.47E+014.01E-02Bell1.42E-013.89E-046.28E-011.72E-032.01E-025.49E-051.95E-025.32E-051.45E-023.97E-052.98E-028.14E-05Bexar2.53E-026.92E-051.12E-013.05E-043.57E-039.76E-063.46E-039.47E-062.58E-037.06E-065.30E-031.45E-05Borden2.86E+017.80E-028.82E+012.41E-014.39E+001.20E-024.25E+001.16E-021.41E+003.85E-037.32E+002.00E-02Bosque2.72E+007.44E-039.98E+002.73E-024.09E-011.12E-033.97E-011.08E-031.85E-015.06E-047.29E-011.99E-03Bowie1.35E+003.68E-033.50E+009.57E-032.09E-015.70E-042.03E-015.53E-045.63E-021.54E-043.41E-019.32E-04Brazoria4.64E+011.27E-011.40E+023.84E-017.10E+001.94E-026.89E+001.88E-022.44E+006.65E-031.20E+013.27E-02Brazos2.17E+015.92E-029.57E+012.62E-013.18E+008.69E-033.09E+008.43E-031.88E+005.13E-036.02E+001.64E-02Briscoe1.48E+004.04E-034.49E+001.23E-022.26E-016.18E-042.19E-016.00E-047.41E-022.02E-043.65E-019.98E-04Brooks9.58E+012.62E-012.87E+027.84E-011.48E+014.03E-021.43E+013.91E-024.50E+001.23E-022.45E+016.69E-02Brown1.30E+003.54E-036.10E+001.67E-021.83E-015.00E-041.78E-014.85E-041.32E-013.62E-042.71E-017.42E-04Burleson4.46E+011.22E-011.48E+024.04E-016.77E+001.85E-026.57E+001.80E-022.65E+007.23E-031.17E+013.21E-02Caldwell1.58E+004.31E-037.31E+002.00E-022.25E-016.14E-042.18E-015.96E-041.60E-014.36E-043.78E-011.03E-03Calhoun2.38E+016.50E-027.79E+012.13E-013.61E+009.87E-033.50E+009.57E-031.40E+003.82E-036.21E+001.70E-02Callahan2.58E+007.06E-031.22E+013.32E-023.65E-019.96E-043.54E-019.67E-042.64E-017.21E-045.41E-011.48E-03Cameron1.42E+003.89E-033.94E+001.08E-022.20E-016.02E-042.14E-015.84E-045.94E-021.62E-043.60E-019.84E-04Carson9.90E-012.71E-035.12E+001.40E-021.42E-013.89E-041.38E-013.77E-049.95E-022.72E-042.67E-017.29E-04Cass2.22E-016.05E-049.77E-012.67E-033.13E-028.54E-053.03E-028.28E-052.26E-026.17E-054.63E-021.27E-04Chambers2.37E+016.47E-028.97E+012.45E-013.55E+009.69E-033.44E+009.40E-031.68E+004.60E-036.38E+001.74E-02Cherokee1.52E+024.15E-014.40E+021.20E+002.33E+016.37E-022.26E+016.18E-027.46E+002.04E-023.90E+011.07E-01Childress2.94E-018.04E-041.38E+003.78E-034.15E-021.13E-044.03E-021.10E-043.00E-028.20E-056.16E-021.68E-046-21Table 6.11 2008 Annual and OSD County-Level Criteria Pollutant Emission Estimates (Cont.)CO-ANNCO-OSDNOXANNNOX-OSDPM10-ANNPM10-OSDPM2.5-ANNPM2.5-OSDSO2-ANNSO2-OSDVOC-ANNVOC-OSDCountytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/dayClay1.12E+013.06E-024.84E+011.32E-011.64E+004.48E-031.59E+004.35E-039.27E-012.53E-032.80E+007.66E-03Cochran1.10E+013.01E-024.45E+011.22E-011.60E+004.38E-031.56E+004.25E-038.97E-012.45E-032.47E+006.74E-03Coke6.20E+001.69E-022.46E+016.73E-029.08E-012.48E-038.80E-012.41E-034.91E-011.34E-031.40E+003.83E-03Coleman3.09E+008.45E-031.45E+013.97E-024.36E-011.19E-034.23E-011.16E-033.15E-018.62E-046.47E-011.77E-03Colorado2.83E+017.73E-028.52E+012.33E-014.31E+001.18E-024.18E+001.14E-021.53E+004.18E-037.06E+001.93E-02Comanche9.49E-022.59E-044.46E-011.22E-031.34E-023.66E-051.30E-023.55E-059.69E-032.65E-051.99E-025.43E-05Concho5.29E+001.45E-022.49E+016.80E-027.46E-012.04E-037.24E-011.98E-035.40E-011.47E-031.11E+003.02E-03Cooke4.07E+011.11E-011.18E+023.24E-016.23E+001.70E-026.04E+001.65E-022.09E+005.71E-031.01E+012.77E-02Coryell1.27E-013.46E-045.58E-011.53E-031.79E-024.88E-051.73E-024.73E-051.29E-023.53E-052.65E-027.23E-05Cottle1.78E+014.87E-025.34E+011.46E-012.74E+007.49E-032.66E+007.26E-038.56E-012.34E-034.48E+001.22E-02Crane4.87E+011.33E-011.80E+024.93E-017.25E+001.98E-027.04E+001.92E-023.38E+009.24E-031.16E+013.17E-02Crockett3.11E+028.50E-019.41E+022.57E+004.77E+011.30E-014.63E+011.26E-011.53E+014.17E-027.79E+012.13E-01Crosby2.90E+007.93E-031.36E+013.73E-024.09E-011.12E-033.97E-011.08E-032.96E-018.09E-046.07E-011.66E-03Culberson3.59E+019.80E-021.08E+022.95E-015.53E+001.51E-025.36E+001.46E-021.70E+004.64E-039.20E+002.51E-02Dallas7.73E+002.11E-023.84E+011.05E-011.12E+003.05E-031.08E+002.96E-037.73E-012.11E-032.21E+006.03E-03Dawson5.66E+011.55E-011.63E+024.45E-018.73E+002.39E-028.47E+002.31E-022.52E+006.89E-031.43E+013.91E-02Denton2.06E+025.62E-019.93E+022.71E+002.99E+018.16E-022.90E+017.91E-021.99E+015.44E-025.83E+011.59E-01DeWitt1.05E+022.86E-013.80E+021.04E+001.57E+014.30E-021.53E+014.17E-027.06E+001.93E-022.79E+017.61E-02Dickens2.40E+016.56E-027.72E+012.11E-013.65E+009.96E-033.54E+009.66E-031.34E+003.65E-035.84E+001.60E-02Dimmit4.50E+011.23E-011.66E+024.53E-016.75E+001.84E-026.55E+001.79E-022.96E+008.10E-031.13E+013.10E-02Duval7.96E+012.17E-012.39E+026.53E-011.22E+013.35E-021.19E+013.25E-023.78E+001.03E-022.02E+015.53E-02Eastland1.52E+004.16E-037.16E+001.96E-022.15E-015.87E-042.08E-015.69E-041.55E-014.24E-043.18E-018.70E-04Ector2.64E+027.21E-017.77E+022.12E+004.06E+011.11E-013.94E+011.08E-011.23E+013.36E-026.64E+011.81E-01Edwards3.99E+011.09E-011.31E+023.58E-016.07E+001.66E-025.89E+001.61E-022.20E+006.01E-031.01E+012.76E-02Ellis2.09E+015.72E-021.04E+022.84E-013.03E+008.27E-032.94E+008.02E-032.10E+005.73E-035.97E+001.63E-02Erath8.49E+002.32E-024.44E+011.21E-011.22E+003.34E-031.19E+003.24E-038.51E-012.33E-032.35E+006.42E-03Falls5.70E-021.56E-042.51E-016.87E-048.04E-032.20E-057.80E-032.13E-055.81E-031.59E-051.19E-023.26E-05Fannin2.84E+007.77E-037.39E+002.02E-024.41E-011.20E-034.28E-011.17E-031.19E-013.24E-047.20E-011.97E-03Fayette1.11E+013.03E-024.69E+011.28E-011.63E+004.46E-031.58E+004.33E-039.16E-012.50E-033.02E+008.24E-03Fisher1.54E+014.20E-025.25E+011.44E-012.31E+006.31E-032.24E+006.12E-039.52E-012.60E-033.67E+001.00E-026-22Table 6.11 2008 Annual and OSD County-Level Criteria Pollutant Emission Estimates (Cont.)CO-ANNCO-OSDNOXANNNOX-OSDPM10-ANNPM10-OSDPM2.5-ANNPM2.5-OSDSO2-ANNSO2-OSDVOC-ANNVOC-OSDCountytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/dayFoard7.94E-012.17E-033.74E+001.02E-021.12E-013.06E-041.09E-012.97E-048.10E-022.21E-041.66E-014.54E-04Fort Bend2.60E+017.09E-029.96E+012.72E-013.85E+001.05E-023.73E+001.02E-021.95E+005.34E-036.66E+001.82E-02Franklin1.45E+013.96E-023.83E+011.05E-012.24E+006.13E-032.17E+005.94E-036.26E-011.71E-033.66E+009.99E-03Freestone4.35E+021.19E+001.22E+033.33E+006.70E+011.83E-016.50E+011.77E-012.04E+015.56E-021.11E+023.04E-01Frio1.91E+015.21E-027.43E+012.03E-012.84E+007.75E-032.75E+007.52E-031.37E+003.74E-034.77E+001.30E-02Gaines1.12E+023.07E-013.47E+029.48E-011.72E+014.69E-021.66E+014.55E-025.72E+001.56E-022.80E+017.65E-02Galveston1.19E+013.26E-024.11E+011.12E-011.81E+004.93E-031.75E+004.78E-037.49E-012.05E-033.15E+008.61E-03Garza1.40E+013.83E-025.11E+011.39E-012.09E+005.70E-032.02E+005.53E-039.61E-012.63E-033.30E+009.00E-03Glasscock1.36E+023.72E-013.81E+021.04E+002.11E+015.76E-022.05E+015.59E-025.78E+001.58E-023.46E+019.44E-02Goliad6.97E+011.91E-012.09E+025.70E-011.06E+012.91E-021.03E+012.82E-023.70E+001.01E-021.75E+014.79E-02Gonzales5.35E+001.46E-021.87E+015.12E-028.04E-012.20E-037.80E-012.13E-033.50E-019.57E-041.39E+003.79E-03Gray2.33E+006.37E-037.20E+001.97E-023.56E-019.72E-043.45E-019.43E-041.20E-013.29E-045.73E-011.57E-03Grayson1.07E+012.91E-023.54E+019.66E-021.62E+004.42E-031.57E+004.28E-036.40E-011.75E-032.78E+007.59E-03Gregg9.58E+012.62E-012.97E+028.12E-011.46E+014.00E-021.42E+013.88E-025.19E+001.42E-022.49E+016.81E-02Grimes1.33E+013.64E-026.59E+011.80E-011.92E+005.25E-031.86E+005.09E-031.33E+003.64E-033.79E+001.03E-02Guadalupe8.96E-012.45E-034.29E+001.17E-021.29E-013.51E-041.25E-013.41E-049.02E-022.47E-042.34E-016.38E-04Hale3.22E+008.80E-031.58E+014.33E-024.59E-011.25E-034.45E-011.22E-033.26E-018.92E-047.63E-012.08E-03Hansford4.53E+011.24E-011.39E+023.80E-016.95E+001.90E-026.74E+001.84E-022.24E+006.11E-031.15E+013.14E-02Hardeman1.70E+014.65E-025.35E+011.46E-012.61E+007.13E-032.53E+006.92E-038.64E-012.36E-034.37E+001.19E-02Hardin5.91E+011.62E-011.92E+025.23E-018.98E+002.45E-028.71E+002.38E-023.44E+009.40E-031.53E+014.18E-02Harris1.24E+013.38E-024.89E+011.34E-011.84E+005.02E-031.78E+004.87E-039.40E-012.57E-033.32E+009.06E-03Harrison5.79E+021.58E+001.84E+035.04E+008.82E+012.41E-018.55E+012.34E-013.26E+018.91E-021.51E+024.13E-01Hartley5.68E-011.55E-032.67E+007.30E-038.01E-022.19E-047.77E-022.12E-045.80E-021.58E-041.19E-013.25E-04Haskell2.02E+005.51E-039.48E+002.59E-022.84E-017.77E-042.76E-017.54E-042.06E-015.62E-044.22E-011.15E-03Hemphill6.43E+021.76E+001.92E+035.23E+009.90E+012.71E-019.61E+012.62E-013.00E+018.18E-021.64E+024.49E-01Henderson3.91E+011.07E-011.11E+023.04E-016.01E+001.64E-025.83E+001.59E-021.87E+005.12E-031.00E+012.74E-02Hidalgo2.27E+026.19E-016.98E+021.91E+003.48E+019.51E-023.38E+019.23E-021.11E+013.03E-025.82E+011.59E-01Hill9.04E+012.47E-014.49E+021.23E+001.31E+013.57E-021.27E+013.46E-029.05E+002.47E-022.58E+017.04E-02Hockley3.19E+018.71E-021.18E+023.23E-014.77E+001.30E-024.63E+001.27E-022.12E+005.80E-038.00E+002.18E-02Hood7.86E+012.15E-013.90E+021.07E+001.13E+013.10E-021.10E+013.01E-027.86E+002.15E-022.24E+016.12E-026-23Table 6.11 2008 Annual and OSD County-Level Criteria Pollutant Emission Estimates (Cont.)CO-ANNCO-OSDNOXANNNOX-OSDPM10-ANNPM10-OSDPM2.5-ANNPM2.5-OSDSO2-ANNSO2-OSDVOC-ANNVOC-OSDCountytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/dayHopkins3.41E+009.31E-039.11E+002.49E-025.26E-011.44E-035.10E-011.39E-031.51E-014.12E-048.56E-012.34E-03Houston2.89E+017.89E-028.59E+012.35E-014.43E+001.21E-024.29E+001.17E-021.48E+004.04E-037.44E+002.03E-02Howard1.19E+023.26E-013.36E+029.17E-011.85E+015.04E-021.79E+014.89E-025.14E+001.40E-023.01E+018.23E-02Hudspeth4.12E+001.12E-021.30E+013.55E-026.26E-011.71E-036.08E-011.66E-032.21E-016.05E-041.01E+002.75E-03Hutchinson1.55E+014.24E-026.98E+011.91E-012.24E+006.11E-032.17E+005.92E-031.42E+003.89E-033.59E+009.81E-03Irion2.33E+026.36E-016.57E+021.79E+003.60E+019.83E-023.49E+019.54E-021.01E+012.76E-025.87E+011.60E-01Jack1.69E+014.63E-028.59E+012.35E-012.43E+006.63E-032.35E+006.43E-031.71E+004.66E-034.36E+001.19E-02Jackson5.69E+011.56E-011.66E+024.53E-018.70E+002.38E-028.44E+002.31E-022.92E+007.97E-031.42E+013.88E-02Jasper2.20E+016.02E-029.34E+012.55E-013.25E+008.88E-033.15E+008.61E-031.81E+004.96E-036.05E+001.65E-02Jefferson4.90E+011.34E-011.84E+025.03E-017.34E+002.01E-027.12E+001.95E-023.46E+009.44E-031.31E+013.59E-02Jim Hogg3.05E+018.33E-028.78E+012.40E-014.71E+001.29E-024.57E+001.25E-021.36E+003.70E-037.74E+002.12E-02Jim Wells1.10E+013.01E-023.69E+011.01E-011.67E+004.56E-031.62E+004.42E-036.49E-011.77E-032.69E+007.36E-03Johnson6.62E+021.81E+003.27E+038.93E+009.57E+012.62E-019.28E+012.54E-016.58E+011.80E-011.89E+025.15E-01Jones7.02E+001.92E-023.30E+019.02E-029.91E-012.71E-039.61E-012.63E-037.17E-011.96E-031.47E+004.01E-03Karnes2.97E+018.12E-021.11E+023.05E-014.45E+001.22E-024.32E+001.18E-022.10E+005.73E-037.95E+002.17E-02Kenedy6.47E+011.77E-011.98E+025.40E-019.94E+002.72E-029.64E+002.63E-023.13E+008.56E-031.66E+014.53E-02Kent2.31E+016.30E-027.83E+012.14E-013.49E+009.54E-033.39E+009.25E-031.36E+003.71E-035.76E+001.57E-02King7.56E+002.07E-023.34E+019.13E-021.08E+002.96E-031.05E+002.87E-037.05E-011.93E-031.63E+004.45E-03Kleberg1.98E+015.42E-028.43E+012.30E-012.95E+008.06E-032.86E+007.82E-031.51E+004.12E-035.39E+001.47E-02Knox2.79E+007.63E-031.11E+013.02E-024.09E-011.12E-033.97E-011.08E-032.20E-016.01E-046.32E-011.73E-03La Salle1.07E+022.92E-013.04E+028.32E-011.65E+014.52E-021.60E+014.38E-024.68E+001.28E-022.71E+017.40E-02Lamb1.62E+004.43E-037.96E+002.18E-022.31E-016.30E-042.24E-016.11E-041.64E-014.49E-043.83E-011.05E-03Lavaca1.03E+022.81E-013.14E+028.57E-011.57E+014.30E-021.53E+014.17E-025.49E+001.50E-022.65E+017.23E-02Lee1.12E+013.07E-024.65E+011.27E-011.66E+004.53E-031.61E+004.39E-039.12E-012.49E-033.00E+008.20E-03Leon1.05E+022.86E-013.33E+029.10E-011.59E+014.36E-021.55E+014.23E-025.91E+001.61E-022.72E+017.43E-02Liberty6.19E+011.69E-011.89E+025.18E-019.46E+002.58E-029.17E+002.51E-023.31E+009.03E-031.60E+014.37E-02Limestone3.16E+028.64E-019.05E+022.47E+004.86E+011.33E-014.72E+011.29E-011.53E+014.17E-028.12E+012.22E-01Lipscomb1.45E+023.95E-016.84E+021.87E+002.12E+015.80E-022.06E+015.63E-021.26E+013.44E-024.02E+011.10E-01Live Oak6.56E+011.79E-012.02E+025.51E-011.00E+012.73E-029.70E+002.65E-023.58E+009.77E-031.67E+014.58E-02Loving1.00E+022.74E-012.93E+028.01E-011.54E+014.22E-021.50E+014.09E-024.62E+001.26E-022.53E+016.90E-026-24Table 6.11 2008 Annual and OSD County-Level Criteria Pollutant Emission Estimates (Cont.)CO-ANNCO-OSDNOXANNNOX-OSDPM10-ANNPM10-OSDPM2.5-ANNPM2.5-OSDSO2-ANNSO2-OSDVOC-ANNVOC-OSDCountytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/dayLubbock1.91E+005.21E-038.97E+002.45E-022.69E-017.36E-042.61E-017.14E-041.95E-015.32E-043.99E-011.09E-03Lynn6.92E+001.89E-021.92E+015.24E-021.07E+002.93E-031.04E+002.84E-032.89E-017.90E-041.75E+004.79E-03Madison1.06E+012.89E-023.96E+011.08E-011.59E+004.33E-031.54E+004.20E-037.41E-012.03E-032.84E+007.77E-03Marion2.08E+015.70E-026.64E+011.81E-013.18E+008.68E-033.08E+008.42E-031.17E+003.20E-035.44E+001.49E-02Martin5.45E+021.49E+001.51E+034.13E+008.45E+012.31E-018.20E+012.24E-012.28E+016.22E-021.38E+023.77E-01Matagorda9.69E+012.65E-012.72E+027.43E-011.49E+014.08E-021.45E+013.96E-024.55E+001.24E-022.48E+016.77E-02Maverick3.34E+019.11E-021.60E+024.37E-014.83E+001.32E-024.68E+001.28E-023.12E+008.53E-038.58E+002.35E-02McCulloch3.16E-028.65E-051.49E-014.07E-044.46E-031.22E-054.33E-031.18E-053.23E-038.82E-066.62E-031.81E-05McLennan2.20E+006.01E-037.53E+002.06E-023.33E-019.08E-043.23E-018.81E-041.37E-013.75E-045.79E-011.58E-03McMullen1.20E+023.28E-013.50E+029.58E-011.85E+015.06E-021.80E+014.91E-025.49E+001.50E-023.04E+018.30E-02Medina9.53E-012.60E-034.48E+001.22E-021.34E-013.67E-041.30E-013.56E-049.72E-022.66E-041.99E-015.45E-04Menard2.23E+006.10E-031.05E+012.87E-023.15E-018.60E-043.05E-018.34E-042.28E-016.22E-044.67E-011.28E-03Midland4.01E+021.10E+001.13E+033.08E+006.21E+011.70E-016.02E+011.64E-011.71E+014.67E-021.02E+022.78E-01Milam2.11E+005.76E-036.58E+001.80E-023.18E-018.69E-043.09E-018.43E-041.25E-013.41E-045.07E-011.38E-03Mitchell2.03E+015.54E-029.54E+012.61E-012.86E+007.82E-032.78E+007.58E-032.07E+005.65E-034.24E+001.16E-02Montague1.03E+022.81E-013.63E+029.92E-011.56E+014.26E-021.51E+014.14E-026.16E+001.68E-022.68E+017.33E-02Montgomery9.87E+002.70E-023.05E+018.33E-021.51E+004.12E-031.46E+003.99E-035.35E-011.46E-032.55E+006.98E-03Moore4.49E+001.23E-022.14E+015.85E-026.35E-011.74E-036.16E-011.68E-034.57E-011.25E-039.77E-012.67E-03Motley1.51E+004.11E-034.48E+001.22E-022.31E-016.31E-042.24E-016.13E-047.24E-021.98E-043.74E-011.02E-03Nacogdoches3.90E+021.07E+001.15E+033.15E+005.98E+011.63E-015.80E+011.59E-011.97E+015.39E-021.01E+022.75E-01Navarro1.69E+014.63E-024.73E+011.29E-012.60E+007.11E-032.53E+006.90E-038.06E-012.20E-034.26E+001.16E-02Newton9.90E+002.70E-023.83E+011.05E-011.48E+004.04E-031.43E+003.92E-037.23E-011.98E-032.68E+007.31E-03Nolan1.62E+014.42E-026.52E+011.78E-012.36E+006.45E-032.29E+006.26E-031.31E+003.58E-033.63E+009.93E-03Nueces5.79E+011.58E-011.66E+024.54E-018.90E+002.43E-028.63E+002.36E-022.84E+007.76E-031.47E+014.03E-02Ochiltree8.01E+012.19E-013.07E+028.38E-011.21E+013.30E-021.17E+013.20E-025.31E+001.45E-022.13E+015.83E-02Oldham6.87E+001.88E-021.90E+015.20E-021.06E+002.91E-031.03E+002.82E-032.87E-017.84E-041.74E+004.76E-03Orange1.06E+012.91E-024.67E+011.27E-011.56E+004.27E-031.52E+004.14E-039.16E-012.50E-032.94E+008.02E-03Palo Pinto1.72E+014.70E-028.71E+012.38E-012.46E+006.73E-032.39E+006.53E-031.73E+004.74E-034.40E+001.20E-02Panola5.35E+021.46E+001.70E+034.64E+008.14E+012.23E-017.90E+012.16E-013.00E+018.19E-021.39E+023.81E-01Parker6.86E+011.88E-013.40E+029.30E-019.91E+002.71E-029.62E+002.63E-026.87E+001.88E-021.96E+015.35E-026-25Table 6.11 2008 Annual and OSD County-Level Criteria Pollutant Emission Estimates (Cont.)CO-ANNCO-OSDNOXANNNOX-OSDPM10-ANNPM10-OSDPM2.5-ANNPM2.5-OSDSO2-ANNSO2-OSDVOC-ANNVOC-OSDCountytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/dayPecos4.72E+021.29E+001.49E+034.06E+007.23E+011.98E-017.02E+011.92E-012.39E+016.54E-021.21E+023.31E-01Polk3.25E+018.88E-021.28E+023.50E-014.83E+001.32E-024.69E+001.28E-022.46E+006.73E-038.69E+002.37E-02Potter6.71E-011.83E-033.16E+008.62E-039.47E-022.59E-049.18E-022.51E-046.84E-021.87E-041.40E-013.83E-04Reagan3.77E+021.03E+001.05E+032.86E+005.84E+011.59E-015.66E+011.55E-011.58E+014.32E-029.54E+012.61E-01Real9.49E-022.59E-044.46E-011.22E-031.34E-023.66E-051.30E-023.55E-059.69E-032.65E-051.99E-025.43E-05Red River1.86E+005.09E-036.24E+001.70E-022.81E-017.68E-042.73E-017.45E-041.15E-013.14E-044.78E-011.31E-03Reeves7.84E+012.14E-012.96E+028.08E-011.18E+013.22E-021.14E+013.13E-025.13E+001.40E-022.07E+015.64E-02Refugio6.89E+011.88E-012.13E+025.81E-011.04E+012.85E-021.01E+012.76E-024.00E+001.09E-021.66E+014.54E-02Roberts2.29E+026.25E-017.06E+021.93E+003.52E+019.61E-023.41E+019.32E-021.12E+013.07E-025.88E+011.61E-01Robertson3.81E+021.04E+001.07E+032.93E+005.87E+011.60E-015.69E+011.56E-011.79E+014.89E-029.76E+012.67E-01Runnels1.23E+013.35E-025.79E+011.58E-011.73E+004.73E-031.68E+004.59E-031.25E+003.41E-032.59E+007.08E-03Rusk5.94E+021.62E+001.64E+034.48E+009.16E+012.50E-018.88E+012.43E-012.71E+017.42E-021.52E+024.14E-01Sabine1.20E+003.27E-033.11E+008.50E-031.86E-015.07E-041.80E-014.92E-045.00E-021.37E-043.03E-018.29E-04San Augustine3.02E+018.24E-021.31E+023.58E-014.44E+001.21E-024.30E+001.18E-022.56E+006.99E-038.35E+002.28E-02San Jacinto2.11E+015.77E-025.96E+011.63E-013.25E+008.89E-033.16E+008.62E-039.98E-012.73E-035.41E+001.48E-02San Patricio2.19E+016.00E-027.51E+012.05E-013.32E+009.06E-033.22E+008.79E-031.38E+003.76E-035.74E+001.57E-02Schleicher6.60E+011.80E-011.90E+025.19E-011.02E+012.78E-029.87E+002.70E-022.98E+008.15E-031.66E+014.52E-02Scurry4.61E+011.26E-011.56E+024.27E-017.00E+001.91E-026.79E+001.85E-022.66E+007.27E-031.17E+013.20E-02Shackelford6.53E+001.78E-023.07E+018.39E-029.21E-012.52E-038.94E-012.44E-036.66E-011.82E-031.37E+003.73E-03Shelby1.50E+024.11E-015.53E+021.51E+002.26E+016.17E-022.19E+015.98E-021.03E+012.81E-024.03E+011.10E-01Sherman2.07E+015.67E-027.43E+012.03E-013.09E+008.46E-033.00E+008.20E-031.39E+003.80E-034.87E+001.33E-02Smith3.09E+018.45E-021.15E+023.14E-014.64E+001.27E-024.50E+001.23E-022.15E+005.86E-038.29E+002.26E-02Somervell1.12E+013.06E-025.55E+011.52E-011.62E+004.42E-031.57E+004.28E-031.12E+003.06E-033.19E+008.72E-03Starr2.27E+026.19E-016.67E+021.82E+003.49E+019.54E-023.39E+019.26E-021.04E+012.84E-025.77E+011.58E-01Stephens1.60E+014.37E-027.58E+012.07E-012.26E+006.17E-032.19E+005.99E-031.63E+004.45E-033.43E+009.37E-03Sterling4.61E+011.26E-011.32E+023.61E-017.12E+001.95E-026.91E+001.89E-022.05E+005.59E-031.17E+013.18E-02Stonewall7.00E+001.91E-023.29E+018.99E-029.87E-012.70E-039.57E-012.62E-037.14E-011.95E-031.46E+004.00E-03Sutton3.03E+028.29E-018.88E+022.43E+004.67E+011.28E-014.53E+011.24E-011.41E+013.86E-027.58E+012.07E-01Tarrant5.97E+021.63E+002.95E+038.07E+008.62E+012.36E-018.36E+012.29E-015.95E+011.63E-011.70E+024.65E-01Taylor2.50E+006.84E-031.20E+013.27E-023.54E-019.68E-043.44E-019.39E-042.55E-016.96E-045.47E-011.50E-036-266-27Table 6.11 2008 Annual and OSD County-Level Criteria Pollutant Emission Estimates (Cont.)CO-ANNCO-OSDNOXANNNOX-OSDPM10-ANNPM10-OSDPM2.5-ANNPM2.5-OSDSO2-ANNSO2-OSDVOC-ANNVOC-OSDCountytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/daytons/yrtons/dayTerrell5.40E+011.48E-011.73E+024.72E-018.26E+002.26E-028.01E+002.19E-022.83E+007.73E-031.38E+013.77E-02Terry1.80E+014.93E-026.24E+011.71E-012.74E+007.48E-032.66E+007.26E-031.05E+002.88E-034.67E+001.28E-02Throckmorton2.87E+007.85E-031.35E+013.69E-024.06E-011.11E-033.93E-011.07E-032.93E-018.01E-046.01E-011.64E-03Titus1.46E-013.98E-046.42E-011.75E-032.05E-025.61E-051.99E-025.44E-051.49E-024.06E-053.05E-028.32E-05Tom Green6.31E+001.72E-022.50E+016.84E-029.23E-012.52E-038.95E-012.45E-034.99E-011.36E-031.42E+003.89E-03Trinity1.30E-013.54E-045.72E-011.56E-031.83E-025.00E-051.78E-024.85E-051.32E-023.62E-052.71E-027.42E-05Tyler3.69E+011.01E-011.58E+024.31E-015.43E+001.48E-025.27E+001.44E-023.08E+008.41E-031.01E+012.77E-02Upshur4.68E+011.28E-011.40E+023.83E-017.18E+001.96E-026.96E+001.90E-022.42E+006.60E-031.21E+013.30E-02Upton7.28E+021.99E+002.08E+035.68E+001.13E+023.08E-011.09E+022.98E-013.19E+018.71E-021.85E+025.06E-01Val Verde1.11E+013.02E-023.09E+018.43E-021.71E+004.68E-031.66E+004.54E-034.68E-011.28E-032.80E+007.65E-03Van Zandt5.53E+001.51E-021.48E+014.05E-028.53E-012.33E-038.28E-012.26E-032.46E-016.73E-041.39E+003.79E-03Victoria4.30E+011.17E-011.35E+023.68E-016.50E+001.78E-026.30E+001.72E-022.51E+006.85E-031.05E+012.88E-02Walker1.55E-014.24E-046.84E-011.87E-032.19E-025.98E-052.12E-025.80E-051.58E-024.32E-053.24E-028.86E-05Waller1.26E+013.46E-023.94E+011.08E-011.92E+005.23E-031.86E+005.08E-037.31E-012.00E-033.11E+008.50E-03Ward7.63E+012.08E-013.34E+029.12E-011.12E+013.07E-021.09E+012.98E-026.25E+001.71E-021.99E+015.43E-02Washington3.45E+009.43E-031.70E+014.65E-024.98E-011.36E-034.83E-011.32E-033.46E-019.45E-049.71E-012.65E-03Webb2.85E+027.79E-018.66E+022.37E+004.38E+011.20E-014.25E+011.16E-011.38E+013.77E-027.26E+011.98E-01Wharton1.04E+022.85E-013.06E+028.36E-011.60E+014.36E-021.55E+014.23E-025.33E+001.46E-022.64E+017.20E-02Wheeler6.12E+021.67E+001.79E+034.89E+009.45E+012.58E-019.17E+012.50E-012.77E+017.58E-021.56E+024.27E-01Wichita1.30E+013.54E-025.83E+011.59E-011.85E+005.04E-031.79E+004.89E-031.24E+003.39E-032.77E+007.57E-03Wilbarger4.02E+001.10E-021.89E+015.16E-025.67E-011.55E-035.50E-011.50E-034.10E-011.12E-038.41E-012.30E-03Willacy4.72E+011.29E-011.36E+023.71E-017.29E+001.99E-027.07E+001.93E-022.08E+005.69E-031.20E+013.28E-02Wilson3.46E-019.45E-041.72E+004.69E-034.99E-021.36E-044.84E-021.32E-043.46E-029.45E-059.86E-022.69E-04Winkler5.64E+011.54E-011.87E+025.10E-018.61E+002.35E-028.35E+002.28E-023.07E+008.38E-031.46E+013.99E-02Wise1.79E+024.89E-018.44E+022.31E+002.60E+017.11E-022.53E+016.90E-021.69E+014.61E-025.03E+011.37E-01Wood8.71E+002.38E-022.95E+018.07E-021.32E+003.60E-031.28E+003.49E-035.42E-011.48E-032.26E+006.18E-03Yoakum5.71E+011.56E-012.20E+026.01E-018.51E+002.33E-028.26E+002.26E-024.04E+001.10E-021.43E+013.89E-02Young8.21E+002.24E-023.86E+011.05E-011.16E+003.16E-031.12E+003.07E-038.37E-012.29E-031.72E+004.69E-03Zapata3.43E+029.38E-011.05E+032.87E+005.28E+011.44E-015.12E+011.40E-011.66E+014.54E-028.81E+012.41E-01Zavala5.19E+001.42E-022.71E+017.41E-027.47E-012.04E-037.25E-011.98E-035.20E-011.42E-031.44E+003.94E-03

# 7.0 Conclusions and Recommendations

This study presents a comprehensive, statewide 2008 emissions inventory for Texas for

drilling rig engines. This inve ntory was prepared using well dr illing activity data obtained

through permit records from the TRC, combined with emissions data derived through detailed

drilling rig engine data collected through a bottom-up survey effort.

Survey data was collected through a phone and email survey which resulted in the

collection of 45 completed surveys obtained from 39 different drilling rig contractors and/or oil

and gas well operators. These surveys were repres entative of over 1,500 wells drilled in Texas in

2008, or about 10% of all wells drilled in that year, and covered all of the major oil and gas

basins in the state (Andarko, East Texas, Ft. Worth/Bend Arch, Permian, and Western Gulf). The

data collected included drilling rig engine sizes (hp), ages, hou rs of operation, and model year.

The 2008 inventory was used as the basis fo r developing 2002 and 2005 year inventories,

as well as projected inventories for 2009 through 2021. As compared to the previous oil and gas

study prepared by TCEQ in 2007 (for a 2005 base yea r), the emission estimates presented in this

study reflect a significant d ecrease in the statewide NO

x 

# emission estimate for 2005 (42,854 tons

per year in this study compared to 119,647 tons per year in the 2007 study). While not as

pronounced, there were also sign ificant decreases in the SO 2 

# and CO emission estimates based

on this study. For VOC, PM 10 

# , and PM 2.5 

# , the estimates contained in this study show slightly

higher estimates than in the previous study.

Further improvements to this inventory coul d be made through the addition of emission

estimates for fracturing operations, as well as additional refinement of the activity data used for

projected years 2009 through 2021.

7-1

# 8.0 References

ARB, 2001. Speciation Profile Database . Internet address:

http://www.arb.ca.gov/ei/spe ciate/interopt01.htm

Bar-Ilan, Amnon; Friesen, Ron; Pollack, Alison; and Hoats, Abigail, 2007. WRAP Area Source

Emissions Inventory Projections and Control St rategy Evaluation Phase II. Prepared for the

Western Governor’s Association. September, 2007.

Bar-Ilan, Amnon; Grant, John; Parikh, Rajashi; Pollack, Alison; Henderer, Doug; Pring, Daniel;

and Sgamma, Kathleen, 2008. Development of Ba seline 2006 Emissions from Oil and Gas

Activity in the Denver-Julesburg Basin. Prepared fo r Colorado Department of Public Health and

Environment Air Pollution Control Division. April, 2008.

Bar-Ilan, Amnon; Parikh, Rajashi; Grant, J ohn; Shah, Tejas; and Pollack, Alison, 2008a.

Recommendations for Improvements to the CENRAP States’ Oil and Gas Emissions Inventories.

Prepared for Central States Regi onal air Partnership. November, 2008

Bar-Ilan, Amnon; Grant, John; Friesen, Ron a nd Pollack, Alison, 2009. Development of Baseline

2006 Emissions from Oil and Gas Activity in the Piceance Basin. Prepared for the Western

Governor’s Association and the Independent Petroleum Associati on of Mountain States. January,

2009.

Bommer, P, 2008. A Primer of Oilwell Drilling, A Basic Text of Oil and Gas Drilling, Seventh

Edition. The University of Texas at Au stin, Petroleum Extension Service. 2008.

Energy Information Administration (EIA), 2009. Supplemental Tables to the Annual Energy

Outlook 2009, Updated Reference Case with ARRA , Data Tables 113 and 114. Data released

April 2009. Washington, D.C. Internet address:

http://www.eia.doe.gov/oiaf/aeo/suppl ement/stimulus/regionalarra.html

Pollack, Alison; Russell, James; Grant, John; Friesen, Ron; Fields, Pa ula; and Wolf, Marty,

2006. Ozone Precursors Emission Inventory for San Juan and Rio Arriba Counties, New Mexico.

Prepared for New Mexico Envi ronment Department. August, 2006.

Russell, James and Pollack, Alison, 2005. Oil and Gas Emissions Inventories for the Western

States. Prepared for Western Gove rnor’s Association. December, 2005.

Texas Commission on Environmental Quality (TCEQ), 2007. Emissions from Oil and Gas

Production Facilities, 2007. Prepared by Ea stern Research Group, Inc. August 31, 2007.

Texas Commission on Environmental Quality (TCEQ), 2009. New Oil and Gas SCCs. Data

provided by Greg Lauderdale, TCEQ. June 2, 2009. Email communication from Greg

Lauderdale, TCEQ to Mike Pri ng, Eastern Research Group, Inc.

8-1

# 8-2 Texas Commission on Environmental Quality (TCEQ), 2009a. NIF 3.0 Formatting for

TEXAER. Data provided by Greg Lauderdale, TCEQ. June 24, 2009. Email communication

from Greg Lauderdale, TCEQ to Mike Pring, Eastern Research Group, Inc.

Texas Railroad Commission (TRC), 2009a. Su mmary of Drilling, Completion and Plugging

Reports Processed for 2002. Accessed June 5, 2009. Internet address:

http://www.rrc.state.tx.us/data/drilling/drillingsummary/2002/ogdc02an.pdf

Texas Railroad Commission (TRC), 2009b. Su mmary of Drilling, Completion and Plugging

Reports Processed for 2005. Accessed June 5, 2009. Internet address:

http://www.rrc.state.tx.us/data/drilling/drillingsummary/2005/ogdc05an.pdf

Texas Railroad Commission (TRC), 2009c. Su mmary of Drilling, Completion and Plugging

Reports Processed for 2008. Accessed June 5, 2009. Internet address:

http://www.rrc.state.tx.us/data/drilling/drillingsummary/2008/annual2008.pdf

U.S. EPA, 2005. User’s Guide for the Fi nal NONROAD2005 Model . EPA-420-R-05-013. U.S.

Environmental Protection Agency, Office of Air and Radiation. December.

U.S. EPA, 2005a. Conversion Factors for Hydrocarbon Emission Components . EPA-420-R-05-

015. U.S. Environmental Protection Agency, Office of Air and Radiation. December.

# Appendix A – Approved Data Collection Plan

# 5608 Parkcrest Drive, Suite 100

Austin, TX 78731

MEMORANDUM

TO: Greg Lauderdale (TCEQ)

FROM: Rick Baker, Mike Pring (ERG)

DATE: April 3, 2009

SUBJECT: Work Order # 582-7-83985-FY09-01, Deliver able 2b- Final Data Collection Plan

This document serves as the final deliverable fo r Task 2 of the Work Order, and includes the

results of ERG’s review of exis ting activity and emissions data, and presents a Data Collection

Plan which identifies the proposed approach for collecting the information needed to develop a

comprehensive emissions inventory for land-based drilling rig engines in the state of Texas in

2008. In addition, as described in the Work Pla n, we have included our recommendations on how

to proceed with the Texas oil and gas dril ling activity emissions estimation project.

The methodology used to develop the 2008 em issions inventory will be based on the 2005

emissions inventory ERG completed for TCEQ in 2007, but will expand on that effort by

improving the analysis and data collection of both activity data and emissions data. ERG will

conduct the data collection survey as per the proposed Data Collection Plan and as approved by

TCEQ.

1.0 Review of Existing Studies, Data, and Industry Websites

Under Task 2, ERG has conducted a literature re view and evaluated existing information and

studies pertinent to the development of a comp rehensive oil and gas drilling activity emissions

inventory for the state of Texas for the year 2008. The results of this research is discussed below

in two parts, the first being a review of existing studies that address estimating emissions from

oil and gas drill rig operations, a nd the second being the results of our review of existing Texas

data available from government and industry websites and publications.

A-1

# 1.1 Review of Existing Studies

As mentioned above, the goal of this project is to improve upon the 2005 emissions inventory

ERG completed for TCEQ in 2007 for drill rig engines by obtaining more highly resolved

activity data, as well as more accurate emissions information. Over the last several years,

numerous studies have been conducted in the western states to devel op area source emission

estimates for oil and gas sources, with subsequent studies improving upon the data collection

methodology and emission estimation approaches in prior studies. The relevant studies ERG has

identified are provided in Table 1.

Table 1. Existing Drill Rig Engine Studies

Report Geographic Coverage Publication Date

Oil and Gas Emission Inventories for the Western

States (WRAP Phase I) WRAP States December, 2005

Ozone Precursors Emission Inventory for San Juan

and Rio Arriba Counties, New Mexico San Juan and Rio

Arriba Counties, New

Mexico August, 2006

Emissions from Oil and Gas Producti on Facilities Texas August, 2007

WRAP Area Source Emissions Inventory

Projections and Control Strategy Evaluation Phase

II WRAP States September, 2007

Development of Baseline 2006 Emissions from Oil

and Gas Activity in the Denver-Julesburg Basin Denver-Julesburg

Basin, Colorado April, 2008

Recommendations for Improvements to the

CENRAP States’ Oil and Gas Emissions

Inventories CENRAP States November, 2008

Development of Baseline 2006 Emissions from Oil

and Gas Activity in the Piceance Basin Piceance Basin,

Colorado January, 2009



# A-2

# As a result of a review of the existing liter ature, ERG has been able to develop a firm

understanding of the types of equipment curre ntly used by industry for different drilling

activities, as well as basic approaches to surv eying and compiling emissions estimates. Based on

this review, ERG anticipates organizing our su rvey based on rig type (drilling rigs vs.

completion/workover rigs), rig engine applicati on (draw works engines, mud pump engines, and

engines for general rig power), whether the rig is mechanical or elec trical, well depth, and

wellbore type (vertical, horizontal). Engine size (hp) will also be critical in our analysis, but the

parameters listed above will dictate the various engine sizes we anticip ate seeing. For example,

many workover and completion rigs may be powe red by a single engine at less than 600 hp,

while rigs used on deep (over 15,000 feet) horizonta l wells may require four or five engines,

ranging in size from 500 to 1,000 hp each.

In addition to process information, example surv eys and survey questions were included in

several studies, and ERG anticipates formulati ng the survey used for this project utilizing

examples provided in these reports.

It should be noted that these ex isting studies were comprehensiv e in nature, inclusive of all

emission sources found at oil and gas exploratio n and production locatio ns. While well drilling

was included as an emission source, this source ca tegory was not a major focus of these efforts.

As such, many of the surveys used in these st udies were sent to the oil and gas producers

themselves, and not directly to the owners and operators of the drill rigs, who are typically

contracted by the producers to drill the well. Once a given well is completed, the drilling

contractor will move on to the next well. Therefore, ERG anticipates focusing our survey efforts

on the drilling contractors themselves, with le ss emphasis on the production companies as has

been done previously.

A-3

# Of the reports listed in Table 1, the CENRAP report appears to be the most relevant for this

study as Texas is one of the CENRAP states covered under the report, and the report also

provides “default” activit y data and emission factors for the five major oil and gas basins in

Texas (Andarko, East Texas, Fort Worth, Permia n, and Western Gulf). While ERG anticipates

developing specific activity data a nd emissions data from our survey efforts as part of this

project, the CENRAP report may be useful for gap-filling and/or valid ation depending upon the

results of our survey activities.

1.2 Review of Existing Activity Data

The primary source of activity data to be used to compile the 2008 drill rig emissions inventory

will come from the Texas Railroad Commi ssion (RRC). ERG has contacted the RRC and

obtained a copy of the “Drilling Pe rmit Master and Trailer” databa se, which contains information

on every application to drill fo r an oil or gas well in Te xas since 1976, including American

Petroleum Institute (API) number, date approved, location (county), wellbore profile, well depth,

spud-in date, and well completion date. ERG is cu rrently in the process of translating this

database into Access for ease of use in estimating emissions. This data will allow us to allocate

emissions spatially (aggregated at the county level) , as well as temporally (based on spud-in date

and well completion date for each individual well). Use of this database will result in a more

highly refined dataset than was used in development of the 2005 emissions inventory, which was

based on total depth drilled by county by wellbore type, with drilling times estimated from the

“worst case” well for each count y/wellbore-type combination.

In addition, by obtaining the complete dataset, ERG will be able to analyze activity data for

multiple years. As described in the work plan, ERG has concerns regarding the

representativeness of activity data for 2008 given th e extreme volatility in the market that year.

Once the data has been properly compiled, ERG will consult with TCEQ and make a final

recommendation as to the base year for this inve ntory effort. Regardless of which base year is

chosen, the RRC data will be used to backcast th e base year inventory to develop the 2002 and

2005 prior year inventories based on drilling perm it records for those years. ERG anticipates

developing 2009 through 2021 projec ted inventories using the base year inventory and

forecasting future activity based on US DOE Ener gy Information Administration projections of

A-4

# oil and gas production for the Southwest and Gulf Coast regions from the Annual Energy

Outlook 2009.

1.3 Review of Industry Websites

Using information available on the Internati onal Association of Drilling Contractors (IADC)

website, we were able to identify many of the la rger drilling contractors in Texas (while there

may be non-IADC members with significant drilli ng activities in Texas, we did not identify any

during our review). A review of the websites for these larger contra ctors provided useful

information regarding the drilling ri g fleets in use in Texas, and we were able to easily assimilate

a dataset with specific equipment information on ove r 225 drill rigs. A few examples of this type

of information can be found at the fo llowing drill rig operator websites:

a) http://www.gwdrilling.com/services/riglist.htm

b) http://www.pioneerdrlg.com/HTML/RigFleet.html

c) http://www.rowancompanies.com/fw/main/Land-Rig-Fleet-61.html

This effort was not exhaustive, and if additional information is needed to gap-fill or supplement

our survey findings, there is additional informa tion that can be obtained online. For example,

Appendix A contains an example “spec sheet” for a specific rig used by Pioneer Drilling,

including specific makes and models of both th e draw works engines and mud pump engines.

ERG will compile this information to the extent possible prior to conducting the survey in order

to familiarize ourselves with the engine makes and models we are likely to encounter through the

survey.

2.0 Data Collection Plan

By obtaining and translating the RRC “Drilling Permit Master and Trailer” database, we will

have highly resolved data on all drilling activity that occurred in Texas during the base year. In

addition to wells that were started and finished during the base year, we will also have data on

drilling activities that commenced during the year preceding the ba se year (but finalized during

the base year), as well as data on wells that were started during the ba se year but were not

A-5

# completed until the following year. Therefore, we feel we have obtained the best activity data

available to use as the basis for the base year inventory.

As we will have obtained the activity data needed to estimate emissions from the RRC database,

the primary focus of our data collection and survey activities will be on obtaining real data from

rig operators who were actively drilling in Texa s in 2008. The goal of this survey will be to

develop a series of “model rig profiles” for different rig types, we ll depths, and geographic

locations (basin-specific profiles are preferred).

Our proposed survey methodology for obtaining this information is provided below.

2.1 Participant Recruitment

In order to encourage survey response, stakeh older support for the study will be sought. At the

current time, ERG has consulted with contacts at the University of Texa s, Southern Methodist

University, the Texas Railroad Commission, a nd the IADC in an effort to obtain an

understanding of well drilling practi ces, and to assist us in encour aging stakeholder participation.

The IADC provided helpful information on industr y practices, but their organization does not

endorse or participate in any survey activities, so further contribution from them may be limited

to feedback on our draft survey ma terials and/or survey approach.

In addition to those sources we have already contacted, ERG anticipates encouraging additional

stakeholder participation by contacting the followi ng trade associations a nd local organizations:

a) Texas Oil and Gas Association (TxOGA)

b) Texas Independent Producers and Royalty Owners Association (TIPRO)

c) Independent Petroleum Asso ciation of America (IPAA)

d) Petroleum Equipment Supplie rs Association (PESA)

e) The Barnett Shale Energy Education Council (BSEEC)

If possible, ERG will attempt to provide inform ation regarding the study and survey to trade

associations before administering the survey to promote cooperation with the study and to

A-6

# identify potential survey participants. We will prep are a draft survey for peer review by members

of the Petroleum Engineering Department at the Un iversity of Texas to obt ain feedback prior to

implementation. ERG will also reques t trade associations and stakehol ders help distribute a letter

of introduction about the project on TCEQ letterhead to the owners and ope rators of drill rigs.

2.2 Mail and Phone Surveys

At this point we do not have a specific list of ta rget respondents, but in ge neral, will seek to find

willing participants through our planned communication with the trade groups as described

above, as well as searches through business listings and directories obtained from such sources

as USA Data. Once we have identified a comprehe nsive listing of likely drilling rig operators,

ERG will obtain the services of a survey contractor to execute this portion of the Data Collection

Plan. ERG will train the survey contractor staff in conducting phone surveys of drill rig

operators, providing background in the purpose of the study and familiarizing staff with industry

terminology they may encounter. Once trained, the surv ey contractor will init iate the survey, first

by phone calls to targeted respondents, then potentially by follow-up with phone, mail or fax

surveys (as needed). Respondents will be asked to specify their preferred survey response mode,

although phone surveys will be encouraged in order to reduce incomplete responses and errors.

Upon completion of the first week of phone surv eys (and at regular inte rvals thereafter), ERG

will review and audit the results of the phone surveys to confirm that we are contacting

participants willing to provide us the needed information over the phone (or willing to continue

with the mail survey), and determine if adjustment s need to be made to the survey or survey

method in order to ensure sufficient response for proper stratification of our model rig profiles.

The survey itself will focus on collecting the fo llowing information for representative, or average

(based on a particular basin or dr illing depth), dri lling operations:

a) The number of engines on a rig

b) Engine make, model, model year, and size (hp)

c) Average load for each engine

d) Engine function (draw works, mud pumps, power)

A-7

# e) Actual engine hour data for well completion (total hours)

f) Actual engine fuel use data for well completion (total fuel use)

g) Engine fuel type (and sulfur content for diesel fuel)

h) Engine-specific emission factors (based on manufacturers’ or vendor da ta) or actual test

data if available

i) Well location (county, API #)

j) Total well drilling time (actual number of drilling days)

k) Total well completion time (number of days needed for well completion activities)

l) Well depth

Depending on how responsive the survey participan t are to the phone survey, and what level of

aggregation they have data ava ilable, we may request “average” da ta for their rigs, or specific

examples based on actual data for specific wells dr illed in the base year. ERG will first attempt

to obtain all the required information via the phone survey, but it is e xpected that specific

information may more readily be obtain ed by following up with a mail survey.

Appendix B presents an example cover letter that will be included with the mail survey, and

Appendix C provides an example of the types of information that will be requested. ERG will

periodically review the mail survey responses to see if adjust ments are needed in order to obtain

a sufficient response rate by checking that all fiel ds/basins are being covered, ensure all wellbore

types are included, and check that the survey adequa tely covers the range of well depths included

in the RRC drilling permit dataset.

2.3 Field Observations

Once ERG has obtained initial responses to our phone and/or mail surveys and with approval

from the TCEQ project manager, ERG will attempt to obtain permission for site visits to active

drilling sites through survey participation a nd stakeholder contacts. ERG’s protocol for

conducting on-site visits includes a standardized data collection form , such as that presented in

Appendix D. This form essentially requests th e same information as requested during the

phone/mail survey, but adds additional contact information and site visit date. On-site

observations of drill rig engine operation and specifications will be used to verify the data

A-8

# collected in the mail and phone surveys, and to at tempt to establish equipment load factors and

any other adjustment factors deemed necessary.

Site visits will be coordinated in advance, obt aining the site location, name of contact, and

date/time for each visit. Site co ntacts will be called one business day in advance to confirm the

time and location for the visit, as well as to determine any site-specific safety or operation

requirements. For example, it is expected that active drilling sites will re quire steel-toed boots,

hard hat, and safety glasses before entry. ERG representatives will adhere to all company

requirements while on site. If necessary, the TCEQ Project Representative sh all obtain an official

letter on TCEQ letterhead explaining the purpose of the study to be presente d to site foremen or

other company representatives as requested.

Once on site, each engine will be assigned a unique id entifier, and data collection will involve an

inspection of each engine located on site to collect the following information:

a) Make and model, model year, and size

b) A description of how each unit is used (obtained from the site foreman)

c) Typical Fuel usage information (gallons per day over the course of the drilling activity)

d) Typical operating schedule (hours per day over the course of the drilling activity)

e) Typical operating load if available

The on-site data collected will be recorded us ing the standard reporting form such as that

provided in Appendix D.

ERG will attempt to arrange for visits to multiple locations/fleets for field observations, and will

seek to arrange visits to different types and si zes of rigs, with a preference for a geographical

distribution reflective of the we ll drilling data obtained from the RRC (as feasible given the

project resources). Preference will be given to comp anies operating multiple drill rigs in order to

improve data collection efficiency.

A-9

# 2.4 Confidentiality

Confidentiality will be stressed to participants participating in the study, and will be addressed in

the survey cover letters and/or phone questionnaire scripts. ERG is particularly sensitive to the

privacy of individuals and busine sses. Therefore all interviews and data collection efforts will

begin with a guarantee of privacy, anonymity, and confidentiality. To ensure survey respondent’s

rights to privacy, respondents will be informed of the research purpose, the kinds of questions

that will be asked, and how TCEQ may use the results of the study. Confidentiality will be

maintained by eliminating names from intervie w records, stripping all respondent-identifying

characteristics from study datase ts. In addition, all project staff will be given explicit training

regarding confidentiality protocols and commitments.

3.0 Emissions Calculation Methodology

Once the Data Collection survey is complete, ERG will develop emission estimates for model rig

fleets which we will then apply to the population of wells from the RRC dataset. It is anticipated

that model rig fleets will be stratified according to:

a) Well location (basin, as identified by County)

b) Well depth (based on RRC data)

c) Well type (vertical, horizontal)

While these parameters are provided in the RRC da taset, and based on our review of available

literature and operator interviews appear to be the most critical parameters in terms of

differentiating wells for emission estimation purpos es, we may encounter other variables that

provide additional distinction be tween our model rig fleets ba sed on our survey results. For

example, we anticipate the total hp of each rig profile to vary by well depth, and although rig

power information is not provided in the RRC data , it will be critical in estimating emissions.

Once we have compiled the survey data into mode l rig fleets, an average emissions profile will

be developed for an average well in that fleet. The emissions profile will be developed for each

model rig fleet using a combination of emissi on and deterioration fact ors obtained through our

survey, EPA’s NONROAD model, a nd/or AP-42 emission factors. For HAPs, emission factors

will be obtained from the SPECIATE database, and/or AP-42.

A-10

# Each well in the RRC dataset will then be assigned to a specific model fleet, and emissions will

be calculated for each well base on scaling emissi ons from the model fleet to each individual

well based on the ratio of the actual well depth for that well to the model fleet average well

depth. For calculating daily emission estimates (for purposes of ozone-season daily estimates),

the total emissions for each wellbore will be evenly divided by the total number of days between

spud date and completion date, as obtained by the RRC dataset. The end result will be an

estimate of the actual emissions for each well for each day of the drilling period.

4.0 Recommendations

ERG recommends that TCEQ proceed with the dr ill rig engine emission estimation project as

described above. By obtaining the RRC well permit database in electroni c format, the activity

data we now have available prov ides us with a much greater le vel of geographical and spatial

resolution for emission estimates than was av ailable when ERG compiled the 2005 oil and gas

emissions inventory. In addition, ou r literature review has indicated that the “state of the art”

emissions estimation approaches and methodology have continued to be refined over the last few

years as regional, state, and local agencies have become increasingly awar e of the magnitude of

emissions from the sources associated with oi l and gas exploration and production. Subsequent

studies of emissions from these sources make us e of previous studies, and build upon those with

further refinement of the activity and emission fact or data used in the estimates. ERG anticipates

being able to continue this evolution for estim ating emissions from drill rig engines in Texas.

The next challenge in this process will be to continue to solicit support from stakeholders,

namely, the trade associations re presenting oil and gas dr ill rig operators, as well as the operators

themselves. Through data available on the IADC website, we have obtained contact information

for many of the major drill rig owners and operators in Texas. While we could proceed to contact

them directly at this point, we feel it will be be neficial to the ultimate success of this project to

obtain the endorsement and support from the industry as a whole through the trade associations if

possible.

A-11

# APPENDIX A

EXAMPLE OF DRILLING RIG INFORMATION AVAILABLE ONLINE

A-12

# APPENDIX B

ADVANCED LETTER TO DRILL RIG OWNERS/OPERATORS --- on TCEQ letter head

(distributed via fax &/or trade associations)

Dear Drill Rig Manager OR <Mr./Ms. LAST NAME>:

The Texas Commission on Environmenta l Quality (TCEQ) requests your help. We are

asking for your voluntary participation in a study a bout engines used in the drilling of new and/or

recompleted oil and gas wells in Texas during 2008. The study will involve rig owners sharing

information regarding the operati ng practices (such as hours of ope ration) and rig configuration

(such as the number and size of engines) in th eir fleet. This information will provide a better

understanding of how drilling rig operations are conducted under real-world practices.

TCEQ contracted with Eastern Research Group (E RG), an independent research organization, to

administer this study. We urge you to participate – the results will improve the accuracy of

TCEQ’s emissions estimates for drilling rigs across the state.

Prominent trade associations are supporting this study, encouraging their members to participate,

including the [TxOGA, IPAA, etc...] These organizations represent the interests of oil and gas

exploration and production companies at the local, state, and national levels and recognize the

value of the study to industry as well as to government.

Your participation is both voluntary and completely confidential. ERG guarantees the

confidentiality of all participants in this study. This means the information your company

provides will be used for statistical purposes only. Responses will be ke pt confidential and will

not be disclosed in identifiable form to anyone other than ERG employees or agents without your

consent. Every ERG employee with access to id entifying information will sign a confidentiality

agreement. This agreement guarantees that we will not disclose any information that may

identify you, such as your address, contact info rmation or worksite locations, unless required by

law.

The study involves 3 easy steps.

1. First, the person most knowledgeable about your business’ drilling ri g operations will be

asked to participate in a short phone survey about the typical ri g configurations and

engine numbers and types used to drill wells in Texas in 2008. In most cases, this survey

will take ten to fifteen minutes.

2. Second, after completion of the phone survey, ERG may send you a written survey

requesting more detailed information about operating practices you employed in drilling

wells in Texas during 2008. In order to mini mize the amount of data we are requesting

from any one participant, we would request data for a select number of drilling

operations, most likely requesting informati on on 2-3 examples for a particular welldepth, oil field or basin, and well type. Howeve r, we would be willing to accept as much

data as made available to us, and can also accept existing data and query it to meet our

A-13

# needs if you have existing data that would be helpful, but is not currently in a format

consistent with our survey.

3. Third, after completion of the surveys, ERG may ask for permission to visit one of your

active drilling sites. Pending your approval, an ERG representative will travel to an active

well site and collect information on each engi ne found on-site. This data includes make,

model, year, load, and engine clock hour readings and fuel usage. Only a small

percentage of companies will be asked to pa rticipate in on-site field data collection.

Again, we appreciate your assistance in this important study. If you have any questions, please

call Greg Lauderdale in the Air Quality Divi sion of TCEQ at 512-239-1433. To contact the

independent research firm conducting the study, call the survey project manager, Rick Baker at

512-407-1823, or email him at rick.baker@erg.com

.

Thank you in advance,

{TCEQ Signature authority}

A-14

# APPENDIX C

DRILL RIG SURVEY QUESTIONS

Part 1. General Site Information

1. Name of Company:

2. Well API #:

3. Contact Name:

4. Number of engines on site:

5. Well Type (Vertical, Horizontal):

6. Well Depth:

7. Total Well Drilling Duration (days):

8. Fuel Type (and sulfur content for diesel

fuel)

Part 2. Engine-Specific Information (for each engine)

Engine

ID Engine Use

(Drawworks,

Mud Pump,

Power) Make/

Model Model

Year Engine

HP Average

Fuel Use

(gallons) Average

Operating

Schedule

(hours) Average

Engine

Load (%)

A-15

# A-16 APPENDIX D

FIELD DATA COLLECTION FORM

Part 1. General Site Information

1. Name of Company:

2. Company ID:

3. Well API #:

4. Site Personnel Contact Name:

5. Site Personnel Title:

6. Site Personnel Phone #:

7. Number of engines on site:

8. Well Type (Vertical, Horizontal)

9. Well Depth:

10. Total Well Drilling Duration (days):

11. Fuel Type (and sulfur content for diesel

fuel)

12. Date of site visit:

Part 2. Engine-Specific Information (for each engine)

Engine

ID Engine Use

(Draw works,

Mud Pump,

Power) Make/

Model Model

Year Engine HP Average

Fuel Use

(gallons) Average

Operating

Schedule

(hours) Average

Engine

Load

(%)

# Appendix B – Survey Letter

# Dear Owner/Operator:

Eastern Research Group (ERG), an independent research organizati on, is conducting a study on

drilling rig engine emissions for the State of Texas for calendar year 2008. ERG is conducting

this study with the support of the Texas Inde pendent Producers and Royalty Owners Association

(TIPRO) and the Texas Oil & Gas Association (TXOGA). These organizations represent the

interests of oil and gas explor ation and production companies in Texas and recognize the value

of the study to industry as well as to government.

We are asking for your voluntary participation in th is study of oil and gas we lls that were drilled

in Texas during 2008. The study will involve sh aring information regarding the operating

practices (such as the hours of operation) and rig configuration (s uch as the number and size of

engines) used dur ing well drilling.

Your participation is voluntary and completely co nfidential, individual wells do not need to be

identified. The information your company provides will be used for statistical purposes only in

order to develop county-level es timates and will not be republished or disseminated for other

purposes. Responses will not be disclosed in identifiable form to anyone other than ERG

employees or agents.

The attached Excel workbook contains our study questions. We are seeking basin specific rig

profiles to complete a typical well in the Anda rko, Bend Arch-Fort Worth, East Texas, Permian,

and Western Gulf basins. For each basin, we woul d like one profile for a vertical well, and a

second profile for a horizontal/directional well. If you operate in multiple basins in Texas, please

complete one worksheet for each basin and well type that you are familiar with. For your

convenience, the county/basin assignments ar e included in the wor kbook in the “Counties by

Basin” worksheet. An example of a completed wo rksheet is also provide d. Your expertise is

valued; please include comments or clarifications!

Your response is requested by June 5, 2009. Comp leted forms may be submitted via email to Len

Boatman at llboatman@gmail.com , or via fax to 512-579-0315 . For further information or

assistance in completing this form, please call Len Boatman at 512-579-0315.

We appreciate your assistance in this important study. If you ha ve any questions on the study,

please feel free to contact me at (919) 468-7840, or via email at mike.pring@erg.com

.

Sincerely,

Mike Pring

Senior Environmental Engineer

Eastern Research Group, Inc.

B-1

# Appendix C – Drill Rig Survey Form

# DRILL RIG SURVEY QUESTIONS

Part 1. General Site Information

Owner/Operator:

Owner/Operator Contact Name:

Owner/Operator Contact Phone:

Please use county or basin averages for each question.

1. Well Locations (county or basin)

2. Well Type (vertical, horizontal, directional)

3. Typical Well Measurement Depth (feet)

4. Typical Well Drilling Duration (days)

5. Typical Number of engines on site

6. Typical Rig Fuel Use (gal/day)

7. Typical Workover/Co mpletion (hours)

8. Typical Workover/Comple tion Engine Size (HP)

9. Fracing; Yes/No; Duration (days)

Part 2. Drill Rig Engine-Specific Informa tion (for each engine on a typical rig).

Engine Function

(Draw works, Mud

Pump, Power) Typical

Make and

Model Typical

Model

Year Typical

Engine

Size (HP) Typical Engine

On-time

(hr/day) Typical Engine

time under load

(hr/day) Typical Engine

Load (%)



# C-1

# Appendix D – Survey DataTable D.1 Survey Data – Horizontal and Directional WellsSurveyID# ofwellscoveredbysurveyWell TypeWellDepthEngineIDEngineFunctionMakeandModelModelYearEngineSize(HP)TotalWellDrillingDaysTotalEngineOn-time(hours)EngineOn-time(hours/1,000feet)AverageLoad %D200a5Directional10,1501(All) ElectricRigCat 351220061192.54096094.5865D200a5Directional10,1502(All) ElectricRigCat 351220061192.54096094.5865D200a5Directional10,1503(All) ElectricRigCat 351220061192.54096094.5865D1805Horizontal8,0001DrawworksCat 3406198540022.554067.5062.5D1805Horizontal8,0002DrawworksCat 3406198540022.554067.5062.5D1805Horizontal8,0003Mud PumpCat 3991985126022.554067.5075D1805Horizontal8,0004Mud PumpCat 3991985126022.554067.5075D1805Horizontal8,0005GeneratorCat 340640022.554067.5080D1805Horizontal8,0006GeneratorCat 340640022.554067.5080D8133Horizontal9,5001DrawworksCat3412B198547513.532434.1125.5D8133Horizontal9,5002DrawworksCat3412B198547513.516217.0525.5D8133Horizontal9,5003Mud PumpCat3508B200595013.516217.0525.8D8133Horizontal9,5004Mud PumpCat3508B200595013.516217.0525.8D8133Horizontal9,5005GeneratorCat 3306198527013.516217.0560D-1Table D.1 Survey Data – Horizontal and Directional Wells (Cont.)SurveyID# ofwellscoveredbysurveyWell TypeWellDepthEngineIDEngineFunctionMakeandModelModelYearEngineSize(HP)TotalWellDrillingDaysTotalEngineOn-time(hours)EngineOn-time(hours/1,000feet)AverageLoad %D8133Horizontal9,5006GeneratorCat 3306198527013.516217.0560D50a34Horizontal10,1091(All) ElectricRigCat 350820069501638437.9960D50a34Horizontal10,1092(All) ElectricRigCat 350820069501638437.9960D11920Horizontal11,5001(All) ElectricRigCat 351220061192.51945639.6560D11920Horizontal11,5002(All) ElectricRigCat 351220061192.51945639.6560D979Horizontal13,0001DrawworksCat 379198455045108083.0840.5D979Horizontal13,0002DrawworksCat 379198455045108083.0840.5D979Horizontal13,0003Mud PumpCat 3508199590045108083.0855.8D979Horizontal13,0004Mud PumpCat 399198912504532424.9255.8D979Horizontal13,0005GeneratorDetroitSeries 6020024004554041.5460D979Horizontal13,0006GeneratorDetroitSeries 6020024004554041.5460D50c3Horizontal14,9001(All) ElectricRigCat3512C20061478671608107.9240D50c3Horizontal14,9002(All) ElectricRigCat3512C20061478671608107.9240D50f11Horizontal17,6681(All) ElectricRigCat3512C2006147872172897.8040D-2Table D.1 Survey Data – Horizontal and Directional Wells (Cont.)SurveyID# ofwellscoveredbysurveyWell TypeWellDepthEngineIDEngineFunctionMakeandModelModelYearEngineSize(HP)TotalWellDrillingDaysTotalEngineOn-time(hours)EngineOn-time(hours/1,000feet)AverageLoad %D50f11Horizontal17,6682(All) ElectricRigCat3512C2006147872172897.8040D1a14Horizontal/Directional10,0001DrawworksDetroitSeries 6020084702150450.4049.4D1a14Horizontal/Directional10,0002Mud Pump #1Detroit16V200020081,2052150450.4035.5D1a14Horizontal/Directional10,0003Mud Pump #2Detroit16V200020081,2052150450.4035.5D1a14Horizontal/Directional10,0004Drawworks/Swivel MotorDetroitSeries 6020084702150450.4049.4D1a14Horizontal/Directional10,0005Generator # 1DetroitSeries 6020084702125225.2090D1a14Horizontal/Directional10,0006Generator # 2DetroitSeries 6020084702125225.2090D1b18Horizontal/Directional10,0001DrawworksDetroitSeries 6020084702150450.4049.4D1b18Horizontal/Directional10,0002Mud Pump #1Detroit16V200020081,2052150450.4035.5D1b18Horizontal/Directional10,0003Mud Pump #2Detroit16V200020081,2052150450.4035.5D1b18Horizontal/Directional10,0004Drawworks/Swivel MotorDetroitSeries 6020084702150450.4049.4D1b18Horizontal/Directional10,0005Generator # 1DetroitSeries 6020084702125225.2090D1b18Horizontal/Directional10,0006Generator # 2DetroitSeries 6020084702125225.2090D162a7Horizontal/Directional11,3351DrawworksCat C-1820056003481671.9960D-3Table D.1 Survey Data – Horizontal and Directional Wells (Cont.)SurveyID# ofwellscoveredbysurveyWell TypeWellDepthEngineIDEngineFunctionMakeandModelModelYearEngineSize(HP)TotalWellDrillingDaysTotalEngineOn-time(hours)EngineOn-time(hours/1,000feet)AverageLoad %D162a7Horizontal/Directional11,3352DrawworksCat C-1820056003481671.9960D162a7Horizontal/Directional11,3353Mud PumpCat 3508200513003440835.9980D162a7Horizontal/Directional11,3354Mud PumpCat 3508200513003440835.9980D162a7Horizontal/Directional11,3355GeneratorCat C-1520054853440835.9960D162a7Horizontal/Directional11,3356GeneratorCat C-1520054853440835.9960S5110Horizontal8,6921DrawworksCat D353197545017.542048.3243S5110Horizontal8,6922DrawworksCat D353197545017.542048.3243S5110Horizontal8,6923Mud PumpCat D398198482517.521024.1666.2S5110Horizontal8,6924Mud PumpCat D398198482517.521024.1666.2S5110Horizontal8,6925GeneratorCat D3412199845017.521024.1640S5110Horizontal8,6926GeneratorCat D3412199845017.521024.1640D11119Horizontal10,5701(All) ElectricRigCat 3512200614761945643.1450D11119Horizontal10,5702(All) ElectricRigCat 3512200614761945643.1450D-4Table D.2 Survey Data – Vertical Wells <= 7,000 feetSurveyID# of wellscoveredby surveyWellTypeWellDepthEngineIDEngineFunctionMake andModelModelYearEngineSize(HP)TotalWellDrillingDaysTotalEngineOn-time(hours)EngineOn-time(hours/1,000feet)AverageLoad %D8037Vertical1,0001DrawworksCummins199045031030.0059D8037Vertical1,0002Mud PumpCat 343198540031030.0049.4D15010Vertical1,8501Drawworksand MudPumpCumminsKT45019805002.51013.5150D15010Vertical1,8502GeneratorDeutz1980502.51013.5120D7448Vertical2,2001DrawCat 3406199047022421.8260D7448Vertical2,2002Mud pumpCat 3408199047021513.6480D7448Vertical2,2003Generator2522421.8225D5172Vertical2,5001DrawCat 3406199242522419.2080D5172Vertical2,5002Mud pumpCat 3406199242522419.2050D5172Vertical2,5003GeneratorJohnDeere2000802129.6020D1726Vertical3,3001DrawworksCummins40019854006.52447.2775D1726Vertical3,3002Mud PumpCummins40019854006.52447.2775D1726Vertical3,3003GeneratorPerkins 4Cylinder1995486.52447.2777.5D7241Vertical3,7001DrawDetroit 602006470102464.8665D-5Table D.2 Survey Data – Vertical Wells <= 7,000 feet (Cont.)SurveyID# of wellscoveredby surveyWellTypeWellDepthEngineIDEngineFunctionMake andModelModelYearEngineSize(HP)TotalWellDrillingDaysTotalEngineOn-time(hours)EngineOn-time(hours/1,000feet)AverageLoad %D7241Vertical3,7002Mud PumpCummins3502002350102464.8670D7241Vertical3,7003Mud pumpCummins3502002350102464.8611D7241Vertical3,7004GeneratorCat 34042006280102464.8650D11323Vertical4,2001DrawworksCat 3408198248962434.2952.65D11323Vertical4,2002Mud PumpJD 600200860062434.2973.9D11323Vertical4,2003GeneratorCat 330419859762434.2965S2313Vertical4,5001Mud Pump 1Cat 353350112458.6777S2313Vertical4,5002DrawworksDetroitSeries 60400112458.67S2313Vertical4,5003Mud Pump 2DetroitSeries 6033011-S2313Vertical4,5004GeneratorJohnDeere80112458.67S316Vertical4,9001GeneratorCat 340620024751140.8237.5S316Vertical4,9002DrawworksCat 340620024751140.8237.5S316Vertical4,9003Mud PumpDetroitSeries 6020005001120.4175S316Vertical4,9004Mud PumpDetroitSeries 6020005001120.4175D-6Table D.2 Survey Data – Vertical Wells <= 7,000 feet (Cont.)SurveyID# of wellscoveredby surveyWellTypeWellDepthEngineIDEngineFunctionMake andModelModelYearEngineSize(HP)TotalWellDrillingDaysTotalEngineOn-time(hours)EngineOn-time(hours/1,000feet)AverageLoad %D14114Vertical5,0001DrawworksCat 34061988425102448.0065D14114Vertical5,0002Mud PumpCat 3503198837510510.0067.5D14114Vertical5,0003Mud PumpCat 34061992425102448.0067.5D14114Vertical5,0004GeneratorDetroitDiesel1990250101224.0075D1519Vertical5,0001DrawworksCat C-152007425524.0049.4D1519Vertical5,0002Mud Pump #1Cat C-152007425524.0035.5D1519Vertical5,0003Mud Pump #2Cat C-152007425524.0035.5D1519Vertical5,0004Drawworks/Swivel MotorCat C-152007425524.0049.4D1519Vertical5,0005GeneratorDetroitSeries 602007470524.0090D11825Vertical5,0001DrawworksCat 34082005550122457.6027D11825Vertical5,0002Mud PumpDetroitSeries 602007550122457.6090D11825Vertical5,0003GeneratorDetroitSeries 602007350122457.6075D13914Vertical5,2001DrawworksCat 3406B199340082436.9232D13914Vertical5,2002DrawworksCat 3406B199340082436.9232D-7Table D.2 Survey Data – Vertical Wells <= 7,000 feet (Cont.)SurveyID# of wellscoveredby surveyWellTypeWellDepthEngineIDEngineFunctionMake andModelModelYearEngineSize(HP)TotalWellDrillingDaysTotalEngineOn-time(hours)EngineOn-time(hours/1,000feet)AverageLoad %D13914Vertical5,2003Mud PumpCat 353E1985435834.6285D13914Vertical5,2004Mud PumpCat 353E198543582436.9285D13914Vertical5,2005GeneratorCat 3306B199340081218.4685D13914Vertical5,2006GeneratorCat 3306B199340081218.4685D1638Vertical6,0001DrawworksCat V711965700102440.0050D1638Vertical6,0002DrawworksCat V711965700102440.0050D1638Vertical6,0003Mud PumpCat V3791975600102440.0075D1638Vertical6,0004Mud PumpCat V3791975600102440.0075D1638Vertical6,0005GeneratorCat 33061975175102440.0075D1524Vertical6,5001(All) ElectricRigDetroitSeries 602008425142451.6970D1524Vertical6,5002(All) ElectricRigDetroitSeries 602008425142451.6970D7050Vertical3,0001DrawworksDetroit8V-9219894758.52468.0040.4D7050Vertical3,0002Mud PumpCat 340619894258.52468.0048.8D7050Vertical3,0003GeneratorJohn Deer4 cylinder1989508.52468.0080D-8Table D.3 Survey Data – Vertical Wells > 7,000 FeetSurveyID# of wellscoveredby surveyWellTypeWellDepthEngineIDEngineFunctionMakeandModelModelYearEngineSize(HP)TotalWellDrillingDaysTotalEngineOn-time(hours)EngineOn-time(hours/1,000feet)AverageLoad %D14219Vertical7,5001DrawworksCat 340620054002048064.0034.6D14219Vertical7,5002DrawworksCat 340620054002048064.0034.6D14219Vertical7,5003Mud PumpCat 341220066502024032.0073.1D14219Vertical7,5004Mud PumpCat C-1820066002024032.0073.1D14219Vertical7,5005GeneratorCat 340620004002024032.0045.5D14219Vertical7,5006GeneratorCat 340620004002024032.0045.5D35114Vertical8,3001DrawworksCat 35319704501228834.7052.4D35114Vertical8,3002DrawworksCat 35319704501228834.7052.4D35114Vertical8,3003Mud PumpCat 39819978001228834.7045.3D35114Vertical8,3004GeneratorCat 340820003501214417.3580D35114Vertical8,3005GeneratorCat 340820003501214417.3580D2009Vertical9,5501(All)ElectricRigCat 351220061192.530.573276.6565D2009Vertical9,5502(All)ElectricRigCat 351220061192.530.573276.6565D-9Table D.3 Survey Data – Vertical Wells > 7,000 Feet (Cont.)SurveyID# of wellscoveredby surveyWellTypeWellDepthEngineIDEngineFunctionMakeandModelModelYearEngineSize(HP)TotalWellDrillingDaysTotalEngineOn-time(hours)EngineOn-time(hours/1,000feet)AverageLoad %D2009Vertical9,5503(All)ElectricRigCat 351220061192.530.573276.6565D8336Vertical9,7501DrawworksCat C-15200447515.518619.0845.3D8336Vertical9,7502DrawworksCat C-15200447515.518619.0845.3D8336Vertical9,7503Mud PumpCat 398197597015.518619.0852.4D8336Vertical9,7504Mud PumpCat 398197597015.518619.0852.4D8336Vertical9,7505GeneratorCat 3406199543515.518619.0880D8336Vertical9,7506GeneratorCat 3406199543515.518619.0880S1212Vertical10,0001(All)ElectricRigCat 35121192.51740840.8065S1212Vertical10,0002(All)ElectricRigCat 35121192.51740840.8065D2062Vertical10,0001DrawworksCat 3408DITA47517.542042.0024.25D2062Vertical10,0002DrawworksCat 3408DITA47517.542042.0024.25D2062Vertical10,0003Mud PumpCatD399PC120017.542042.0024.25D2062Vertical10,0004Mud PumpCatD399PC120017.542042.0024.25D-10Table D.3 Survey Data – Vertical Wells > 7,000 Feet (Cont.)SurveyID# of wellscoveredby surveyWellTypeWellDepthEngineIDEngineFunctionMakeandModelModelYearEngineSize(HP)TotalWellDrillingDaysTotalEngineOn-time(hours)EngineOn-time(hours/1,000feet)AverageLoad %D2062Vertical10,0005GeneratorCat 340642517.521021.00100D2062Vertical10,0006GeneratorCat 340642517.521021.00100D1913Vertical10,0001DrawworksCat C-1320064101536036.0067.5D1913Vertical10,0002DrawworksCat C-1320064101536036.0067.5D1913Vertical10,0003Mud PumpCat C-1520065001536036.0067.5D1913Vertical10,0004Mud PumpCat C-1520065001536036.0067.5D1913Vertical10,0005GeneratorCat C-1520065001536036.0080D1913Vertical10,0006GeneratorCat C-1520065001536036.0080D37101Vertical10,3001DrawworksCat 353198145013.532431.4645.5D37101Vertical10,3002DrawworksCat 353198145013.532431.4645.5D37101Vertical10,3003Mud PumpCat 379198155013.532431.4636.9D37101Vertical10,3004Mud PumpCat 379198155013.532431.4636.9D37101Vertical10,3005GeneratorCat 3406199542513.516215.7390D37101Vertical10,3006GeneratorCat 3406199542513.516215.7390D-11Table D.3 Survey Data – Vertical Wells > 7,000 Feet (Cont.)SurveyID# of wellscoveredby surveyWellTypeWellDepthEngineIDEngineFunctionMakeandModelModelYearEngineSize(HP)TotalWellDrillingDaysTotalEngineOn-time(hours)EngineOn-time(hours/1,000feet)AverageLoad %D1903Vertical10,5001DrawworksCat C-1520054753072068.5767.5D1903Vertical10,5002DrawworksCat C-1520054753072068.5767.5D1903Vertical10,5003DrawworksCat C-1520054753072068.5767.5D1903Vertical10,5004Mud PumpCat 39912003072068.5767.5D1903Vertical10,5005Mud PumpCat 39912003072068.5767.5D1903Vertical10,5006GeneratorCat 341210003036034.2962.5D1903Vertical10,5007GeneratorCat 341210003036034.2962.5D12112Vertical10,8001DrawworksCat C-15200448532.578072.2227.2D12112Vertical10,8002DrawworksCat C-15200448532.578072.2227.2D12112Vertical10,8003Mud PumpCatD399TA2004120032.578072.2235.5D12112Vertical10,8004Mud PumpCatD399TA2004120032.578072.2235.5D12112Vertical10,8005GeneratorCat C-15200448532.539036.1135D12112Vertical10,8006GeneratorCat C-15200448532.539036.1135D1628Vertical11,5001DrawworksCat C-1820056002560052.1760D-12Table D.3 Survey Data – Vertical Wells > 7,000 Feet (Cont.)SurveyID# of wellscoveredby surveyWellTypeWellDepthEngineIDEngineFunctionMakeandModelModelYearEngineSize(HP)TotalWellDrillingDaysTotalEngineOn-time(hours)EngineOn-time(hours/1,000feet)AverageLoad %D1628Vertical11,5002DrawworksCat C-1820056002560052.1760D1628Vertical11,5003Mud PumpCat 3508200513002530026.0980D1628Vertical11,5004Mud PumpCat 3508200513002530026.0980D1628Vertical11,5005GeneratorCat C-1520054852530026.0960D1628Vertical11,5006GeneratorCat C-1520054852530026.0960D2151Vertical12,2001Mud PumpDetroit2000200812051638431.4860D2151Vertical12,2002Mud PumpDetroit2000200812051638431.4860D2151Vertical12,2003DrawworksDetroitSeries 6020084701638431.4850D2151Vertical12,2004DrawworksDetroitSeries 6020084701638431.4850D2151Vertical12,2005GeneratorDetroitSeries 6020084701619215.7450D2151Vertical12,2006GeneratorDetroitSeries 6020084701619215.7450D50b16Vertical12,2111(All)ElectricRigCat3512C200614782150441.2740D50b16Vertical12,2112(All)ElectricRigCat3512C200614782150441.2740D-13D-14Table D.3 Survey Data – Vertical Wells > 7,000 Feet (Cont.)SurveyID# of wellscoveredby surveyWellTypeWellDepthEngineIDEngineFunctionMakeandModelModelYearEngineSize(HP)TotalWellDrillingDaysTotalEngineOn-time(hours)EngineOn-time(hours/1,000feet)AverageLoad %D50d6Vertical12,4831(All)ElectricRigCat3512C200614782252842.3040D50d6Vertical12,4832(All)ElectricRigCat3512C200614782252842.3040D50g9Vertical17,7781(All)ElectricRigCat3512C2006147855132074.2540D50g9Vertical17,7782(All)ElectricRigCat3512C2006147855132074.2540D50e10Vertical17,9701(All)ElectricRigCat3512C20061478842016112.1940D50e10Vertical17,9702(All)ElectricRigCat3512C20061478842016112.1940

# Appendix E – Total Drilling Depth by County by Model Rig Well Type

Category

(see file “TCEQ Drilling Rig En gine Report_Appendices.xls”)

# Appendix F – Emission FactorsTable F.1 Emission Factors forVertical Wells > 7,000 FeetEmission Factor (ton/1,000 feet)Pollutant2002200520082009201020112012210320142015201620172018201920202021CO2.07E-012.06E-011.50E-011.49E-011.49E-011.45E-011.45E-011.11E-011.11E-011.11E-011.10E-019.82E-026.44E-026.42E-026.41E-023.55E-02NOx4.61E-014.60E-014.15E-014.14E-014.11E-013.88E-013.88E-013.62E-013.62E-013.61E-013.42E-013.38E-012.99E-012.98E-012.98E-012.52E-01PM104.03E-024.02E-022.32E-022.32E-022.27E-022.27E-022.27E-021.31E-021.30E-021.30E-021.27E-021.20E-028.29E-038.27E-038.25E-034.31E-03PM2.53.91E-023.90E-022.25E-022.25E-022.20E-022.20E-022.20E-021.27E-021.26E-021.26E-021.24E-021.16E-028.04E-038.02E-038.00E-034.18E-03SO25.92E-025.92E-026.25E-036.25E-032.97E-042.97E-042.97E-042.73E-042.73E-042.73E-042.73E-042.73E-042.73E-042.73E-042.73E-042.58E-04TOG5.61E-025.59E-023.85E-023.85E-023.82E-023.74E-023.73E-023.11E-023.11E-023.11E-023.10E-022.82E-022.09E-022.08E-022.08E-021.29E-02VOC5.52E-025.50E-023.79E-023.79E-023.76E-023.68E-023.67E-023.07E-023.06E-023.06E-023.05E-022.78E-022.05E-022.05E-022.05E-021.27E-02Formaldehyde8.25E-038.22E-035.67E-035.66E-035.62E-035.50E-035.49E-034.58E-034.58E-034.57E-034.56E-034.15E-033.07E-033.07E-033.06E-031.89E-03Methanol1.68E-051.68E-051.16E-051.15E-051.15E-051.12E-051.12E-059.34E-069.33E-069.32E-069.31E-068.47E-066.26E-066.25E-066.24E-063.86E-06Benzene1.12E-031.12E-037.70E-047.69E-047.63E-047.48E-047.46E-046.23E-046.22E-046.21E-046.20E-045.65E-044.17E-044.17E-044.16E-042.57E-04Acetaldehyde4.12E-034.11E-032.83E-032.83E-032.81E-032.75E-032.74E-032.29E-032.29E-032.28E-032.28E-032.08E-031.53E-031.53E-031.53E-039.45E-04Naphthalene5.05E-055.03E-053.47E-053.46E-053.44E-053.36E-053.36E-052.80E-052.80E-052.80E-052.79E-052.54E-051.88E-051.88E-051.87E-051.16E-05o-xylene1.91E-041.90E-041.31E-041.31E-041.30E-041.27E-041.27E-041.06E-041.06E-041.06E-041.05E-049.60E-057.10E-057.08E-057.07E-054.37E-05Cumene1.12E-051.12E-057.70E-067.69E-067.63E-067.48E-067.46E-066.23E-066.22E-066.21E-066.20E-065.65E-064.17E-064.17E-064.16E-062.57E-06Ethylbenzene1.74E-041.73E-041.19E-041.19E-041.18E-041.16E-041.16E-049.66E-059.64E-059.63E-059.62E-058.75E-056.47E-056.46E-056.45E-053.99E-05Styrene3.36E-053.35E-052.31E-052.31E-052.29E-052.24E-052.24E-051.87E-051.87E-051.86E-051.86E-051.69E-051.25E-051.25E-051.25E-057.72E-06p-xylene5.61E-055.59E-053.85E-053.85E-053.82E-053.74E-053.73E-053.11E-053.11E-053.11E-053.10E-052.82E-052.09E-052.08E-052.08E-051.29E-051,3-butadiene1.07E-041.06E-047.32E-057.31E-057.25E-057.10E-057.09E-055.92E-055.91E-055.90E-055.89E-055.36E-053.97E-053.96E-053.95E-052.44E-05m-xylene3.42E-043.41E-042.35E-042.35E-042.33E-042.28E-042.28E-041.90E-041.90E-041.89E-041.89E-041.72E-041.27E-041.27E-041.27E-047.85E-05Toluene8.24E-048.21E-045.66E-045.65E-045.61E-045.49E-045.49E-044.58E-044.57E-044.57E-044.56E-044.15E-043.07E-043.06E-043.06E-041.89E-04n-hexane8.97E-058.94E-056.16E-056.15E-056.11E-055.98E-055.97E-054.98E-054.98E-054.97E-054.96E-054.52E-053.34E-053.33E-053.33E-052.06E-05Propionaldehyde5.44E-045.42E-043.74E-043.73E-043.70E-043.63E-043.62E-043.02E-043.02E-043.01E-043.01E-042.74E-042.02E-042.02E-042.02E-041.25E-042,2,4-trimethylpentane1.68E-041.68E-041.16E-041.15E-041.15E-041.12E-041.12E-049.34E-059.33E-059.32E-059.31E-058.47E-056.26E-056.25E-056.24E-053.86E-05Lead1.69E-061.69E-069.74E-079.73E-079.52E-079.55E-079.53E-075.49E-075.47E-075.46E-075.35E-075.04E-073.48E-073.47E-073.46E-071.81E-07Manganese1.61E-061.61E-069.28E-079.26E-079.06E-079.09E-079.07E-075.22E-075.21E-075.20E-075.10E-074.80E-073.32E-073.31E-073.30E-071.73E-07Mercury1.21E-061.21E-066.96E-076.95E-076.80E-076.82E-076.81E-073.92E-073.91E-073.90E-073.82E-073.60E-072.49E-072.48E-072.47E-071.29E-07Nickel7.66E-077.64E-074.41E-074.40E-074.31E-074.32E-074.31E-072.48E-072.48E-072.47E-072.42E-072.28E-071.58E-071.57E-071.57E-078.19E-08Antimony1.45E-061.45E-068.35E-078.34E-078.16E-078.18E-078.17E-074.70E-074.69E-074.68E-074.59E-074.32E-072.98E-072.98E-072.97E-071.55E-07Arsenic2.02E-072.01E-071.16E-071.16E-071.13E-071.14E-071.13E-076.53E-086.52E-086.50E-086.37E-086.00E-084.15E-084.13E-084.12E-082.16E-08Cadmium1.61E-061.61E-069.28E-079.26E-079.06E-079.09E-079.07E-075.22E-075.21E-075.20E-075.10E-074.80E-073.32E-073.31E-073.30E-071.73E-07F-1Table F.1 Emission Factors for Vertical Wells > 7,000 Feet (Cont.)Emission Factor (ton/1,000 feet)Pollutant2002200520082009201020112012210320142015201620172018201920202021Cobalt4.44E-074.42E-072.55E-072.55E-072.49E-072.50E-072.50E-071.44E-071.43E-071.43E-071.40E-071.32E-079.12E-089.09E-089.07E-084.74E-08Phosphorous5.12E-065.10E-062.95E-062.94E-062.88E-062.89E-062.88E-061.66E-061.65E-061.65E-061.62E-061.52E-061.05E-061.05E-061.05E-065.48E-07Selenium4.03E-074.02E-072.32E-072.32E-072.27E-072.27E-072.27E-071.31E-071.30E-071.30E-071.27E-071.20E-078.29E-088.27E-088.25E-084.31E-08Chlorine1.39E-051.38E-057.98E-067.97E-067.80E-067.82E-067.80E-064.49E-064.48E-064.47E-064.38E-064.13E-062.85E-062.84E-062.84E-061.48E-06Table F.2 Emission Factors forVertical Wells > 7,000 FeetEmission Factor (ton/1,000 feet)Pollutant2002200520082009201020112012210320142015201620172018201920202021CO6.17E-024.13E-023.16E-023.09E-023.01E-022.95E-022.93E-022.86E-022.78E-022.23E-022.21E-021.39E-024.37E-034.21E-034.05E-033.91E-03NOx2.21E-011.82E-011.49E-011.47E-011.33E-011.30E-011.12E-018.76E-028.28E-027.46E-027.41E-026.20E-024.02E-023.97E-022.76E-021.36E-02PM109.25E-036.68E-034.46E-034.43E-034.00E-033.94E-033.68E-033.37E-033.32E-032.66E-032.64E-031.67E-035.39E-045.16E-044.94E-044.75E-04PM2.58.97E-036.48E-034.33E-034.30E-033.88E-033.83E-033.57E-033.27E-033.22E-032.58E-032.56E-031.62E-035.23E-045.00E-044.79E-044.60E-04SO23.06E-023.06E-023.23E-033.23E-031.53E-041.53E-041.53E-041.53E-041.53E-041.43E-041.43E-041.28E-041.11E-041.11E-041.11E-041.11E-04TOG1.43E-027.54E-036.72E-036.63E-036.53E-036.44E-036.39E-036.30E-036.21E-035.85E-035.81E-035.28E-034.68E-034.64E-034.61E-034.58E-03VOC1.41E-027.42E-036.62E-036.53E-036.43E-036.34E-036.29E-036.20E-036.12E-035.76E-035.72E-035.20E-034.60E-034.57E-034.53E-034.51E-03Formaldehyde2.11E-031.11E-039.89E-049.75E-049.60E-049.48E-049.39E-049.26E-049.14E-048.60E-048.54E-047.77E-046.88E-046.83E-046.78E-046.74E-04Methanol4.30E-062.26E-062.02E-061.99E-061.96E-061.93E-061.92E-061.89E-061.86E-061.75E-061.74E-061.58E-061.40E-061.39E-061.38E-061.37E-06Benzene2.87E-041.51E-041.34E-041.33E-041.31E-041.29E-041.28E-041.26E-041.24E-041.17E-041.16E-041.06E-049.35E-059.28E-059.22E-059.16E-05Acetaldehyde1.05E-035.54E-044.94E-044.87E-044.80E-044.74E-044.69E-044.63E-044.57E-044.30E-044.27E-043.88E-043.44E-043.41E-043.39E-043.37E-04Naphthalene1.29E-056.78E-066.05E-065.97E-065.88E-065.80E-065.75E-065.67E-065.59E-065.26E-065.23E-064.75E-064.21E-064.18E-064.15E-064.12E-06o-xylene4.87E-052.56E-052.29E-052.25E-052.22E-052.19E-052.17E-052.14E-052.11E-051.99E-051.97E-051.80E-051.59E-051.58E-051.57E-051.56E-05Cumene2.87E-061.51E-061.34E-061.33E-061.31E-061.29E-061.28E-061.26E-061.24E-061.17E-061.16E-061.06E-069.35E-079.28E-079.22E-079.16E-07Ethylbenzene4.44E-052.34E-052.08E-052.05E-052.02E-052.00E-051.98E-051.95E-051.93E-051.81E-051.80E-051.64E-051.45E-051.44E-051.43E-051.42E-05Styrene8.60E-064.52E-064.03E-063.98E-063.92E-063.87E-063.83E-063.78E-063.73E-063.51E-063.48E-063.17E-062.81E-062.78E-062.76E-062.75E-06p-xylene1.43E-057.54E-066.72E-066.63E-066.53E-066.44E-066.39E-066.30E-066.21E-065.85E-065.81E-065.28E-064.68E-064.64E-064.61E-064.58E-061,3-butadiene2.72E-051.43E-051.28E-051.26E-051.24E-051.22E-051.21E-051.20E-051.18E-051.11E-051.10E-051.00E-058.89E-068.82E-068.75E-068.70E-06m-xylene8.74E-054.60E-054.10E-054.04E-053.98E-053.93E-053.89E-053.84E-053.79E-053.57E-053.54E-053.22E-052.85E-052.83E-052.81E-052.79E-05Toluene2.11E-041.11E-049.89E-059.74E-059.60E-059.47E-059.39E-059.26E-059.13E-058.60E-058.54E-057.76E-056.87E-056.82E-056.77E-056.73E-05n-hexane2.29E-051.21E-051.08E-051.06E-051.04E-051.03E-051.02E-051.01E-059.94E-069.36E-069.29E-068.45E-067.48E-067.43E-067.37E-067.33E-06F-2Table F.2 Emission Factors for Vertical Wells > 7,000 Feet (Cont.)Emission Factor (ton/1,000 feet)Pollutant2002200520082009201020112012210320142015201620172018201920202021Propionaldehyde1.39E-047.31E-056.52E-056.43E-056.33E-056.25E-056.19E-056.11E-056.03E-055.67E-055.63E-055.12E-054.54E-054.50E-054.47E-054.44E-052,2,4-trimethylpentane4.30E-052.26E-052.02E-051.99E-051.96E-051.93E-051.92E-051.89E-051.86E-051.75E-051.74E-051.58E-051.40E-051.39E-051.38E-051.37E-05Lead3.89E-072.81E-071.88E-071.86E-071.68E-071.66E-071.55E-071.42E-071.39E-071.12E-071.11E-077.00E-082.26E-082.17E-082.07E-081.99E-08Manganese3.70E-072.67E-071.79E-071.77E-071.60E-071.58E-071.47E-071.35E-071.33E-071.07E-071.06E-076.66E-082.16E-082.06E-081.97E-081.90E-08Mercury2.78E-072.00E-071.34E-071.33E-071.20E-071.18E-071.10E-071.01E-079.96E-087.99E-087.91E-085.00E-081.62E-081.55E-081.48E-081.42E-08Nickel1.76E-071.27E-078.48E-088.41E-087.60E-087.49E-086.99E-086.41E-086.31E-085.06E-085.01E-083.16E-081.02E-089.80E-099.38E-099.02E-09Antimony3.33E-072.40E-071.61E-071.59E-071.44E-071.42E-071.32E-071.21E-071.20E-079.59E-089.50E-086.00E-081.94E-081.86E-081.78E-081.71E-08Arsenic4.63E-083.34E-082.23E-082.21E-082.00E-081.97E-081.84E-081.69E-081.66E-081.33E-081.32E-088.33E-092.69E-092.58E-092.47E-092.37E-09Cadmium3.70E-072.67E-071.79E-071.77E-071.60E-071.58E-071.47E-071.35E-071.33E-071.07E-071.06E-076.66E-082.16E-082.06E-081.97E-081.90E-08Cobalt1.02E-077.35E-084.91E-084.87E-084.40E-084.34E-084.05E-083.71E-083.65E-082.93E-082.90E-081.83E-085.93E-095.67E-095.43E-095.22E-09Phosphorous1.17E-068.48E-075.67E-075.62E-075.08E-075.01E-074.67E-074.28E-074.22E-073.38E-073.35E-072.12E-076.84E-086.55E-086.27E-086.03E-08Selenium9.25E-086.68E-084.46E-084.43E-084.00E-083.94E-083.68E-083.37E-083.32E-082.66E-082.64E-081.67E-085.39E-095.16E-094.94E-094.75E-09Chlorine3.18E-062.30E-061.54E-061.52E-061.38E-061.36E-061.27E-061.16E-061.14E-069.17E-079.07E-075.73E-071.85E-071.77E-071.70E-071.63E-07Table F.3 Emission Factors forDirectional/Horizontal WellsEmission Factor (ton/1,000 feet)Pollutant2002200520082009201020112012210320142015201620172018201920202021CO1.27E-011.09E-017.77E-027.75E-027.72E-026.47E-026.45E-026.40E-026.38E-026.36E-026.07E-022.66E-022.61E-022.59E-022.58E-021.34E-02NOx5.20E-015.22E-014.11E-014.11E-014.00E-013.55E-013.37E-012.52E-012.49E-012.43E-012.24E-012.01E-012.00E-011.99E-011.99E-011.80E-01PM102.43E-021.97E-021.12E-021.12E-021.06E-029.28E-039.38E-036.75E-036.74E-036.75E-036.65E-033.92E-033.90E-033.88E-033.86E-032.70E-03PM2.52.36E-021.91E-021.09E-021.08E-021.03E-029.00E-039.10E-036.55E-036.54E-036.55E-036.45E-033.81E-033.79E-033.76E-033.74E-032.62E-03SO27.36E-027.36E-027.77E-037.77E-033.69E-043.69E-043.69E-043.00E-043.00E-043.00E-043.00E-042.83E-042.83E-042.83E-042.83E-042.76E-04TOG3.95E-023.51E-022.25E-022.25E-022.17E-021.64E-021.53E-022.08E-022.06E-022.03E-022.00E-021.34E-021.34E-021.33E-021.33E-021.11E-02VOC3.89E-023.46E-022.22E-022.21E-022.14E-021.62E-021.50E-022.05E-022.03E-022.00E-021.97E-021.32E-021.32E-021.31E-021.31E-021.09E-02Formaldehyde5.81E-035.17E-033.31E-033.30E-033.20E-032.42E-032.25E-033.07E-033.04E-032.98E-032.95E-031.98E-031.97E-031.96E-031.96E-031.63E-03Methanol1.18E-051.05E-056.75E-066.74E-066.52E-064.93E-064.58E-066.25E-066.19E-066.08E-066.01E-064.03E-064.01E-064.00E-063.99E-063.33E-06Benzene7.90E-047.03E-044.50E-044.49E-044.35E-043.29E-043.05E-044.17E-044.13E-044.06E-044.01E-042.69E-042.68E-042.67E-042.66E-042.22E-04Acetaldehyde2.90E-032.58E-031.65E-031.65E-031.60E-031.21E-031.12E-031.53E-031.52E-031.49E-031.47E-039.88E-049.84E-049.81E-049.79E-048.16E-04Naphthalene3.55E-053.16E-052.03E-052.02E-051.96E-051.48E-051.37E-051.88E-051.86E-051.83E-051.80E-051.21E-051.20E-051.20E-051.20E-059.99E-06F-3F-4Table F.3 Emission Factors for Directional/Horizontal Wells (Cont.)Emission Factor (ton/1,000 feet)Pollutant2002200520082009201020112012210320142015201620172018201920202021o-xylene1.34E-041.19E-047.66E-057.63E-057.39E-055.59E-055.19E-057.09E-057.02E-056.90E-056.82E-054.57E-054.55E-054.54E-054.53E-053.78E-05Cumene7.90E-067.03E-064.50E-064.49E-064.35E-063.29E-063.05E-064.17E-064.13E-064.06E-064.01E-062.69E-062.68E-062.67E-062.66E-062.22E-06Ethylbenzene1.22E-041.09E-046.98E-056.96E-056.74E-055.09E-054.73E-056.46E-056.40E-056.29E-056.22E-054.17E-054.15E-054.14E-054.13E-053.44E-05Styrene2.37E-052.11E-051.35E-051.35E-051.30E-059.86E-069.16E-061.25E-051.24E-051.22E-051.20E-058.07E-068.03E-068.01E-067.99E-066.66E-06p-xylene3.95E-053.51E-052.25E-052.25E-052.17E-051.64E-051.53E-052.08E-052.06E-052.03E-052.00E-051.34E-051.34E-051.33E-051.33E-051.11E-051,3-butadiene7.50E-056.68E-054.28E-054.27E-054.13E-053.12E-052.90E-053.96E-053.92E-053.85E-053.81E-052.55E-052.54E-052.54E-052.53E-052.11E-05m-xylene2.41E-042.14E-041.37E-041.37E-041.33E-041.00E-049.31E-051.27E-041.26E-041.24E-041.22E-048.20E-058.16E-058.14E-058.12E-056.77E-05Toluene5.80E-045.17E-043.31E-043.30E-043.20E-042.42E-042.24E-043.06E-043.03E-042.98E-042.95E-041.98E-041.97E-041.96E-041.96E-041.63E-04n-hexane6.32E-055.62E-053.60E-053.59E-053.48E-052.63E-052.44E-053.33E-053.30E-053.25E-053.21E-052.15E-052.14E-052.14E-052.13E-051.78E-05Propionaldehyde3.83E-043.41E-042.18E-042.18E-042.11E-041.59E-041.48E-042.02E-042.00E-041.97E-041.94E-041.30E-041.30E-041.29E-041.29E-041.08E-042,2,4-trimethylpentane1.18E-041.05E-046.75E-056.74E-056.52E-054.93E-054.58E-056.25E-056.19E-056.08E-056.01E-054.03E-054.01E-054.00E-053.99E-053.33E-05Lead1.02E-068.28E-074.71E-074.70E-074.46E-073.90E-073.94E-072.84E-072.83E-072.84E-072.79E-071.65E-071.64E-071.63E-071.62E-071.14E-07Manganese9.73E-077.89E-074.49E-074.47E-074.25E-073.71E-073.75E-072.70E-072.70E-072.70E-072.66E-071.57E-071.56E-071.55E-071.54E-071.08E-07Mercury7.30E-075.91E-073.37E-073.35E-073.19E-072.78E-072.81E-072.03E-072.02E-072.03E-071.99E-071.18E-071.17E-071.16E-071.16E-078.11E-08Nickel4.62E-073.75E-072.13E-072.12E-072.02E-071.76E-071.78E-071.28E-071.28E-071.28E-071.26E-077.45E-087.42E-087.37E-087.33E-085.14E-08Antimony8.76E-077.10E-074.04E-074.02E-073.82E-073.34E-073.38E-072.43E-072.43E-072.43E-072.39E-071.41E-071.41E-071.40E-071.39E-079.74E-08Arsenic1.22E-079.86E-085.61E-085.59E-085.31E-084.64E-084.69E-083.38E-083.37E-083.38E-083.32E-081.96E-081.95E-081.94E-081.93E-081.35E-08Cadmium9.73E-077.89E-074.49E-074.47E-074.25E-073.71E-073.75E-072.70E-072.70E-072.70E-072.66E-071.57E-071.56E-071.55E-071.54E-071.08E-07Cobalt2.68E-072.17E-071.23E-071.23E-071.17E-071.02E-071.03E-077.43E-087.41E-087.43E-087.31E-084.32E-084.29E-084.27E-084.24E-082.98E-08Phosphorous3.09E-062.50E-061.43E-061.42E-061.35E-061.18E-061.19E-068.57E-078.56E-078.58E-078.44E-074.98E-074.96E-074.93E-074.90E-073.44E-07Selenium2.43E-071.97E-071.12E-071.12E-071.06E-079.28E-089.38E-086.75E-086.74E-086.75E-086.65E-083.92E-083.90E-083.88E-083.86E-082.70E-08Chlorine8.37E-066.78E-063.86E-063.85E-063.65E-063.19E-063.23E-062.32E-062.32E-062.32E-062.29E-061.35E-061.34E-061.33E-061.33E-069.31E-07

# Appendix G – Annual and OSD Co unty-Level Emission Estimates

(Criteria Pollutants a nd HAPs, 2002, 2005, 2008-2021)

(see file “TCEQ Drilling Rig En gine Report_Appendices.xls”)