Insert for New Section IX.B.1.c. Immediately following 1.b.

IX.

B.

1.

c. Definition of gas well

Comment: Several commenters mentioned that the proposed 

definition of “gas well” was unclear due to the term “principal

production” used in describing what the well produces. One 

commenter requests that the definition of gas well be modified 

to include each respective state’s definition of gas well. The 

commenter states that by doing this, the EPA would eliminate any 

confusion associated with having to apply different criteria 

(NSPS versus state regulations) for how to define a well-type in 

assessing the applicability of the rule. 

Response: 

In response to comments requesting further clarity in the 

definition, the EPA has revised the definition. The proposed 

definition was “Gas well means an onshore well, the principal 

production of which at the mouth of the well is gas.” In the 

final rule, in response to the comments we received, the EPA has 

revised the definition to exclude the term “at the mouth of the 

well.” 

EPA’s intent in setting standards for completion of 

hydraulically fractured gas wells is to require reduced 
emissions completions for wells where infrastructure is 

generally present to get recovered natural gas to market. We 

believe that the final rule will result in control of 

hydraulically fractured gas wells drilled in the four formation 

types generally accepted as gas-producing formations: (1) highpermeability gas, (2) shale gas, (3) other tight reservoir rock, 

or (4) coal seam. We believe that the wording changes made to 

the definition of “gas well” clarify the intent so that 

implementing agencies and industry will not be burdened with 

complex applicability determinations.

With respect to using state gas well definitions, basing 

applicability on different definitions from state to state could 

introduce inconsistencies that are counter to the goal of 

nationwide regulation. We believe the NSPS, being a national 

rule, should contain a single definition applicable nationwide.

Comment: One commenter states that based on the EPA’s 

discussion in Section 4 of the Technical Support Document, it 

appears the EPA’s intent is to require reduced emissions 

completions only for natural gas wells. The commenter supports 

that the EPA applied reduced emissions completions only to 

natural gas wellhead facilities and excluded oil wellhead 

facilities and other types of gas wells which have little or no 

VOC emissions. The commenter states that, as shown on page 4-13 

on Table 4.4 “Nationwide Baseline Emissions from Uncontrolled 
Oil and Gas Well Completions and Recompletions” of the Technical 

Support Document, there are only 134 TPY of VOCs emissions from 

oil well completions and recompletions for the entire U.S., 

which is not worth regulating.

One commenter recommends the following revision: “Gas well 

means a well, the principal production of which at the mouth of 

the well is [add: hydrocarbon gas, not CO2]. . .Well means an oil 

or gas well, a hole drilled for the purpose of producing oil or 

gas, or a well into which fluids are injected.” One commenter 

proposes the following revision: “Gas well means a well, [DELETE 

the principal production of which at the mouth of the well is 

gas] completed for production of natural gas from one or more 

gas zones or reservoirs. Such wells contain no completions for 

the production of crude oil. The commenter also proposes the 

following revision: Gas well means a well [STRIKETHROUGH: the 

principal production of which at the mouth of the well is gas.] 

[ADD TEXT: completed for production of natural gas from one or 

more gas zones or reservoirs. Such wells contain no completions 

for the production of crude oil.]”

Response: Although some wells drilled in crude oil formations 

may produce associated gas along with the oil, the EPA does not 

have sufficient data on VOC emissions during completion of 

hydraulically fractured oil wells to set standards for these 
operations at this time. As a result, the final rule will not 

apply to completion of oil wells.