Department of Environmental Quality 

To protect, conserve and enhance the quality of Wyoming's 

environment for the benefit of current and future generations. 

Matthew H. Mead, Governor Todd Parfitt, Director 

June 16, 2014 

Comments submitted via email to oilandgas.whitepapers@epa.gov 

Re: Five Technical White Papers on Sources of Emissions in the Oil and Gas Sector 

To Whom It May Concern at the U.S. Environmental Protection Agency Office of Air Quality Planning 

and Standards: 

The State of Wyoming Department of Environmental Quality (WDEQ) appreciates the opportunity to 

comment on the five technical white papers on potentially significant sources of emissions in the oil and 

gas sector, which U.S. Environmental Protection Agency (EPA) Office of Air Quality Planning and 

Standards (OAQPS) released for external peer review on April 15, 2014. The white papers address 

emissions and mitigation techniques for methane and volatile organic compounds (VOCs) from sources in 

the oil and gas sector. 

WDEQ has been regulating VOCs emissions from onshore oil and gas production sites and pipeline 

facilities for over twenty years. The Department has issued over 29,000 permitting actions to date for air 

emissions associated with production equipment, completion activities, liquids unloading, and 

compression facilities. The oil and gas sector is comprised of many separate and distinct operations, 

which may vary in type and application by well field or by company-determined development strategies. 

Variation is common in the oil and gas industry. EPA noted in its draft repmi An Assessment qf the 

Environmental Implications of Oil and Gas Production: A Regional Case Study that "[t]he oil and natural 

gas resources in Region 8 are distinct from other reserves located in the United States." (pg. ES--1) It is 

WDEQ's experience that such distinction results in highly varied and production-specific air emissions 

and operations. EPA's five white papers are based on a collection of studies and assessments that provide 

high level summary information~ but lack site or field specific analyses. WDEQ appreciates both the · 

challenge and necessity of obtaining current production and site and field data. WDEQ obtains this 

information during permitting actions and utilizes it as a basis for determining emissions. EPA should 

expand the scope of these white papers to include more data samples and site specific production 

information because this data will greatly enhance EPA's ability to gauge the effectiveness of any 

potential control strategy. EPA is encouraged to expand the scope of their white papers to include more 

data samples and site specific production information in order to effectively judge the impact of any 

potential control strategy. 

In addition to the general recommendation to use more site specific equipment and production data, the 

WDEQ provides additional comments on each white paper. Comments are organized by type of 

equipment or operation. 

The control determination for rod packing emissions is the same as that of New Source Performance 

Standard 0000, which is appropriate. WDEQ's application of best available control technology 

(BACT) results in similar requirements for compression units. The Division is also aware that some 

operators are investigating the implementation of a vapor recovery system (VRU) to collect packing 

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Wyoming Department of Environmental Quality Comments 

Five Technical White Papers on Sources of Emissions in the Oil and Gas Sector 

June 16,2014 

Page 2 

emissions and route them back into the gas stream or into the fuel system. There are site specific 

concerns for such control, including potential back pressure issues. 

Cost values for control of emissions from the compressor seals will vary significantly depending on the 

gas composition and size of compressor. It is important for EPA to consider these variables when 

determining size categories and applicable emissions controls. A small vapor compressor used to control 

tank emissions or produced gas does not have the same control opportunities as a large, mainline 

compression unit, even though their VOC emissions could be comparable. 

WDEQ reviewed EPA's questions at the end of the white paper. Based on the technical and operational 

nature of the questions, the Department recommends that EPA continue their cooperative work with 

operators to adequately address these questions. 

Emissions from completions and ongoing production of hydraulically fractured oil wells 

EPA's assessment of emissions was focused primarily on oil well development in North Dakota, which is 

not representative of completions and ongoing production from hydraulically fractured oil wells in 

various locations across the state of Wyoming. In many cases, site specific limitations such as the quality 

of produced gas and availability of pipeline determine whether a reduced emissions completion (REC), or 

green completion, can be utilized. EPA should take additional measures, including surveying oil and gas 

operators, to determine the feasibility of requiring the capture of produced gas from hydraulically 

fractured oil wells. 

WDEQ is aware of additional measures that operators may use to reduce flaring emissions associated 

with hydraulically fractured oil wells. Companies may install mechanical refrigeration units, JouleThompson skids, or similar natural gas liquids (NGL) recovery equipment to reduce the heat content of 

the gas being f1ared. These mitigation measures help reduce flaring emissions while providing a 

potentially valuable product for sale. EPA should note that in some states with minor source BACT 

authority, the use of NGL recovery and storage equipment can trigger permitting, so operators may have 

_ ~o 9bt~in_pe~rr1its pri9r to installing and ?perating equipment designe~ ~o re~uce flaring ~missi01~s. 

When considering control technologies and work practices to reduce emissions associated with 

completions, EPA must consider workplace safety. WDEQ is aware that some forms of flaring, such as 

pit flaring, are performed for safety reasons. Some operators use pit flaring to control VOC emissions 

from drilling fluids, which pose a potential fire and/or explosion hazard. The uses ofREC may reduce the 

need for pit flares, however there may be instances when pit flaring will still be necessary as a matter of 

safety. 

Monitoring of control devices needs to be addressed when examining potential ways to reduce VOC 

emissions from produced gas from oil wells. The composition of the produced gas can vary significantly 

and this in turn can affect the design and operation of any emissions controls, especially flares or 

combustors. WDEQ has an operational standard that non-emergency flares be smokeless. EPA should 

consider effective monitoring methods to ensure proper operation. In some instances, required periodic 

Method 9 readings may not be the most effective monitoring method. 
Wyoming Department of Environmental Quality Comments 

Five Technical White Papers on Sources of Emissions in the Oil and Gas Sector 

June 16,2014 

Page 3 

In addition to smokeless provisions, WDEQ requires monitoring of a pilot flame or a combination of 

temperature and flow monitoring to ensure proper operation of the flare or combustor and to verify that 

VOC vapors are not being vented. Other states also require some form of monitoring to demonstrate the 

control is working properly. EPA should review current monitoring practices for controls that reduce 

VOC emissions from hydraulically fractured oil wells and consider such monitoring in any determination 

they make to require VOC emissions controls. 

WDEQ addresses equipment leaks in two parts and on a case-by-case basis. The first part is emission 

quantification. Fugitive VOC emissions are determined using either a representative or actual component 

count, a determination of service for each component, an assumed leak rate, and representative gas 

analyses. Component count and gas analysis are the two most variable factors for oil and gas production 

sites. Component counts vary based on well production and company-determined processing equipment. 

WDEQ has noted significant variations in both factors, even within the same producing field. WDEQ 

uses representative gas analyses to determine VOC content of the leaking vapors. EPA should work with 

states and operators to obtain a better understanding of the variability of fugitive equipment leaks before 

developing control requirements or emissions standards. 

The second part of WDEQ methodology for addressing equipment leaks is leak detection and repair 

(LDAR). As previously mentioned WDEQ addresses equipment leaks on a case-by-case basis and does 

not unilaterally require LDAR programs at production sites. For example, a single well producing low 

API gravity crude oil may have insignificant VOC emissions from leaks, but an oil well that produces 

high API gravity oil and gas may have significant emissions from equipment leaks. EPA should consider 

such variability when considering controlling or reducing fugitive VOC emissions from equipment leaks. 

Not only do VOC emissions from equipment leaks vary among production sites, but so do the LDAR 

programs implemented by various operators throughout Wyoming. WDEQ applies minimum standards 

to LDAR programs, but just as production site configuration and operation vary, so too does the 

application of LDAR. Some production wells are closely grouped in a producing field, while wells in 

other fields cat1 be a-notable aistmfce-apart. Some-production sites feed-to licjuias collectioi1 facilities 

while others separate and store liquids onsite. There is also notable variation in the way operators go 

about determining leaks. Some operators use optical imaging devices to detect the presence of leaks and 

then apply derived leak rates to the leak. Other operators will measure emissions from the leak using a 

Method 21 monitoring instrument. Both approaches are effective at identifying leaks, but may have 

significantly different implementation costs. There may be technical issues that affect an instrument's 

ability to detect leaks from a single component. There may also be environmental factors, such as wind 

speed, that affect the implementation of a LDAR program that is based on an optical imaging device. 

Before determining whether to require LDAR, EPA must review and consider the differences between the 

various forms of LDAR. 

Liquids unloading 

EPA's assessment of liquids unloading focused on technologies and work practices used within the well 

casing or annulus. WDEQ has not required operators to implement a specific type of liquid unloading 

practice, but focuses on controlling emissions when unloading events occur. Best management practices 

(BMP) have been implemented through permits and permit requirements specific to well blowdown and 

venting. These practices include blowing down the well through existing tanks and separators, which 
Wyoming Department of Environmental Quality Comments 

Five Technical White Papers on Sources of Emissions in the Oil and Gas Sector 

June 16, 2014 

Page 4 

may be controlled by combustion devices, or sending produced gas and liquids from blowdowns to a 

central gathering facility. 

Oil and gas production sites are located in very different geographical areas throughout the country. At 

some locations, line power may be readily available, whereas at other more remote locations line power is 

simply not available. WDEQ relies on the experience of the operators to determine the best liquids 

unloading procedure and implement BMP on a case-by-case basis to minimize emissions from unloading 

events. Operators are required to maintain records of blowdown events and resulting emissions, and 

provide them to the Division. Based on historical data from such reports for natural gas wells, VOC 

emissions from blowdowns are often in the order of pounds. EPA should examine mitigation and control 

measures that can be applied on the surface both at the well head and downstream of the well head. In 

addition to using existing production equipment to control VOC emissions from blowdown events, 

WDEQ is aware of specialized portable equipment that can be used to control emissions from unloading 

events. EPA should review additional methods for control unloading emissions because although there 

are many effective control measures, not every control measure will be effective in every situation. 

Pneumatic devices 

EPA's analysis of pneumatic devices was very narrow. EPA reviewed older studies that only looked at 

approximately 15 controllers in the rocky mountain region. WDEQ understands that it was EPA's intent 

to survey controllers in well fields throughout the United States, however a sample size of only 15 

controllers does not adequately represent the distribution of pneumatic controllers in the region. WDEQ's 

recent experience is that while line power is becoming more prevalent, there are still many areas in 

Wyoming that are too remote for line power. Gas driven pneumatic devices are, and will continue to be, 

necessary for some operations in specific locations. 

EPA's control determination relied heavily on the use of electric devices or devices operated with 

instrument air. In remote locations, a generator would be required to operate the electric devices and 

electric air compressor. A fuel-fired compressor could be used in place of a fuel-fired generator to 

produce instrument air. In either case, there would be additional emissions associated with either electric 

-or -instrument air- d-evices. --EPA nl.ust consider ancillary equiprnent and- associated air- ernissions for 

remote locations. 

EPA did not evaluate a wide variety of control measures for pneumatic devices. Operators in Wyoming 

control VOC emissions from gas driven pneumatic devices in a variety of ways. Some operations route 

emissions to the fuel gas system, while others route emissions to existing VOC controls. In some 

instances, operators take advantage of equipment consolidation and reduce the overall number of gas 

driven pneumatic devices. EPA should consider additional measures for reducing VOC emissions from 

pneumatic devices. 

WDEQ noted that EPA's evaluation did not address pneumatic pumps used for heat trace systems, which 

can be a significant source of VOC emissions. EPA did consider pneumatic pumps used for chemical 

injection, however these pumps tend to be much smaller with fewer emissions. WDEQ requires operators 

to reduce VOC emissions from pneumatic heat trace pumps through the application of BACT. EPA 

should consider requiring operators to control VOC emissions from their pneumatic heat trace pumps. 

WDEQ also noted that EPA did not include actual emissions data from 2012 or 2013. More recent data 

will likely demonstrate lower emissions from new equipment as a result of the application ofNew Source 

Performance Standard Subpart 0000, which requires low bleed pneumatic devices at oil and gas 
Wyoming Department of Environmental Quality Comments 

Five Technical White Papers on Sources of Emissions in the Oil and Gas Sector 

June 16,2014 

Page 5 

production sites. WDEQ further noted that as. result of using older information, emissions of greenhouse 

gases (GHG) were determined using the older global warming potential (GWP) of 21 for methane. 

Effective January 1, 2014, the GWP of methane is 25 (78FR71904-71981). EPA should base C02e 

greenhouse gas emissions on current GWPs, which will be used to determine 2013 reported GHG 

emissions from oil and gas sources that are subject to the mandatory greenhouse gas (GHG) repotiing 

rule. 

In conclusion, oil and gas development is a diverse and complex industry, and any effective emissions 

reduction strategy must account for the varying types of operations and varying types of production. 

WDEQ suggests that EPA revise the five white papers to include more recent and robust emissions data 

and to account for the variability in oil and gas fields and operations. WDEQ appreciates the opportunity 

to provide comments on these five white papers, and looks forward to working with EPA to control 

emissions in the oil and gas sector. 

Should you have any questions, please contact me at (307) 777-7391. 

Steven A. Dietrich 

WDEQ Air Quality Administrator 

cc: Todd Parfitt, WDEQ Director 

Jeremiah Williamson, Office of the Attorney General 

Jerimiah Rieman, Governor Mead's Policy Office 

Jennifer Cederle, AQD 

Cole Anderson, AQD