This comment letter response contains two parts:   

(1) The original submittal from the commenter.

(2) A data base printout of EPA’s response to each point raised by the commenter.

Notes about the response letters:

• The response letters were generated by a data base used to track the content of all public

comment submittals and ensure that the Agency responds to each. Each comment letter

was assigned a Letter ID that corresponds to the last four digits of the docket number of the

original comment (as posted on www.regulations.gov).

• Each response letter includes: comment text; an EPA‐assigned comment code; and an

individual response. These are described and explained below.  

• The data base contains Comment text from the letters submitted by commenters.  

Many hard copy letters were scanned into electronic format for inclusion in the data

base. As a result, there may be some typographical errors attributable to optical

character recognition issues.  However, all original submittals were reviewed in the

process of drafting responses to ensure that the comment content was understood and

appropriately addressed.

• The content of each comment letter was divided into topic areas and assigned a unique

Comment ID.  Additionally, one or more Comment Codes (i.e., unique topic area ID) was

assigned to each discrete point raised by a commenter. This information was added to

the data base. To inform final rulemaking decisions, all comments and information

received on a given topic were reviewed by technical experts in each rule area (e.g., on

construction requirements).  

• Following decisions on the final rule requirements, Individual responses were drafted

by topic area to ensure completeness and consistency of the responses with the final

rule and other responses to similar comments.  Each discrete point made by a

commenter was given a unique response.

• Upon completion of comment responses, all information was entered into the data base.

Each letter response is a compilation of each comment and its individual response,

compiled in the order of the original comment letter.  As a result of this process, there is

repetition in the response text.  The Agency believes this approach ensures completeness

and attention to each comment letter that was submitted.   

• All comments in a topic area were reviewed, evaluated, and responded to concurrently.  

Responses on each topic area are compiled and are also available in the rulemaking docket.
Or-ei!on 

Theodore R. Kulongoski, Governor 

November 26, 2008 

Water Docket, 

Environmental Protection Agency, 

Mailcode: 2822T, 

1200 Pennsylvania Ave., NW., 

Washington, DC 20460 

RE: Docket ID No. EPA-HQ-OW-2008-0390 

p. 1 

2a+o~ -- ~3'1D 

Water Resources Department 

North Mall Office Building 

725 Summer Street NE, Suite A 

Salem, OR 97301-1266 

503-986-0900 

FAX 503-986-0904 

DEC 0 4 2008 

The Oregon Water Resources Department thanks you for the opportunity to provide these 

comments on proposed UIC rules for carbon dioxide geologic sequestration wells. 

III Proposed Regulatory Alternatives 

We recommend alternative #3 . 

These rules are more of a performance standard than construction standards. In order to fully 

protect groundwater aquifers and the environment, the rules should more fully regulate the 

construction of class VI wells by the use of detailed construction standards along with 

performance standards. , 

146.86 Injection Well Construction Requirements. 

(b)(3) This rule indicates that the wells can be grouted with cement in one or more stages. 

The problem with cementing in stages is that it is possible to have cold joints that may allow 

the movement of water or fluids within the annular space. We would prefer that the grout be 

placed in one continuous operation without a significant interruption. Significant interruption 

means that the grout should not be allowed to set up to a point that a cold joint would be 

created when continuing to place grout after an interruption . We suggest that the interruption 

should not be more than 72 hours if Portland Cement is used, 48 hours if High Early Strength 

Type III Portland Cement is used or 6 hours if High-Alumina Cement is used. Other 

interruption times would vary depending on the final set time of the proposed grout. 

We also suggest that there be a requirement that the continuous cementing take a minimum 

amount of grout to complete the seal . For example, the rules should require that a minimum 

of 120% to 130% of the estimated volume of sealing material be used when sealing. 

Although this wouldn't guarantee an adequate seal, the chances of a sufficient seal would be 

much greater with the appropriate amount of grout. Too little grout would raise a red flag . 

NOV 2 8 2008 
Docket ID No. EPA-HQ-OW-2008-0390 

November 26, 2008 

Page 2 

p. 2 

146.87 Logging, Sampling, and Testing prior to Injection well Operation. (b) This rule states that the Director may accept cores from nearby wells if the owner or operator 

can demonstrate that core retrieval is not possible and that such cores are representative of conditions at the well. The problem is that cores from nearby wells may not be indicative of the conditions at the well being constructed. If possible a down-hole video should be made to accurately show the conditions at the well site . 

146.89 Mechanical Integrity. 

This rule uses the term "significant" in a number of places when describing leaks . There should be either a definition of "significant" or the wells should be adequately sealed so that there are no leaks. 

146.90 Testing and Monitoring Requirements. 

(c) We support extensive corrosion monitoring and control, at least until collectively we know 

more about how cement will react to long-term contact with C02. 

146.92 Injection Well Plugging. 

The rules describe plugs as a way to abandon class VI wells. In order to ensure that these wells 

are properly abandoned and that they don't become a health hazard or a health threat in the future the abandonment of class VI wells should consist of completely filling them from the bottom up to land surface with an approved sealant (i .e . cement). This assumes that the well was properly constructed in the first place. If the well wasn't constructed properly in the first place then another abandonment method may be necessary to properly protect the groundwater resource . 

146.93 Post-Injection Site Care and Site Closure. 

(e) We ask that the site closure reports be posted on-line. 

Sincerely, 

'Do-, Wt * aa 

Donn Miller 

Hydrogeologist 

Cc : Barbara Priest, Oregon Department of Environmental Quality 
Letter ID: 0270 

Commenter: Donn Miller 

Organization: State of Oregon, Water Resources Department 

Letter ID: 0270 Comment ID: 22885 Letter Lines: 42 to 49 

Comment Code: 2300 1.7 Comments on the Alternatives Considered 

Comment: III Proposed Regulatory Alternatives 

We recommend alternative #3. 

These rules are more of a performance standard than construction standards. In 

order to fully protect groundwater aquifers and the environment, the rules should 

more fully regulate the construction of class VI wells by the use of detailed 

construction standards along with performance standards. 

Individual Response: EPA agrees with the commenters that Regulatory Alternative 3 is 

appropriate. The technical requirements in Alternative 3 (and the final GS rule) build upon the 

long-standing UIC regulatory framework for deep wells and are appropriately tailored to address 

the unique nature of full-scale CO2 GS, including the volumes of CO2 to be injected, the 

buoyant and mobile nature of the injectate, and its corrosivity in the presence of water. 

The tailored approach in this alternative (and the final GS rule) modifies the existing UIC 

requirements for site characterization, area of review, well construction, mechanical integrity 

testing, monitoring, well plugging, post-injection site care, and site closure, to address full-scale 

GS. This approach promotes USDW protection, incorporates flexibility or the discretion of the 

permitting authority when appropriate, seeks to limit burden on owners or operators and 

permitting agencies, and provides a foundation for national consistency in permitting of GS 

projects. 

EPA adds that the construction requirements at §146.86 provide an appropriate level of 

protection from endangerment to USDWs that is based upon the existing UIC framework for 

deep wells. The new tailored construction requirements in the final GS rule offer a balance 

between specific standards and flexibility to address site-specific conditions and are tailored to 

address the unique nature of CO2 GS (i.e., very large volumes, very long time-periods, and 

pressurized reservoirs). 

Letter ID: 0270 Comment ID: 22886 Letter Lines: 51 to 70 

Comment Code: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) 

Comment: 146.86 Injection Well Construction Requirements. 

1
(b)(3) This rule indicates that the wells can be grouted with cement in one or 

more stages. The problem with cementing in stages is that it is possible to have 

cold joints that may allow the movement of water or fluids within the annular 

space. We would prefer that the grout be placed in one continuous operation without 

a significant interruption. Significant interruption means that the grout should 

not be allowed to set up to a point that a cold joint would be created when 

continuing to place grout after an interruption. We suggest that the 

interruption should not be more than 72 hours if Portland Cement is used, 48 

hours if High Early Strength Type III Portland Cement is used or 6 hours if 

High-Alumina Cement is used. Other interruption times would vary depending on the 

final set time of the proposed grout. 

We also suggest that there be a requirement that the continuous cementing take a 

minimum amount of grout to complete the seal . For example, the rules should 

require that a minimum of 120% to 130% of the estimated volume of sealing material 

be used when sealing. Although this wouldn't guarantee an adequate seal, the 

chances of a sufficient seal would greater with the appropriate amount 

of grout. Too little grout would raise a red flag. 

Individual Response: EPA believes that staged cementing of long-string casing cement is 

acceptable with very long casing lengths where one continuous cementing cannot be performed. 

EPA agrees that the period between grouting jobs should be minimized, although that period, 

known in the industry as "waiting for cement," is dependent on the time that it takes for the grout 

in any one stage to set up and cure. As soon as the grout is finished in one stage the staging 

equipment is moved and new grout is poured. 

EPA adds that the specifics the commenter mentions should be addressed on an individual 

project basis. With their permit applications, operators must submit well construction procedures, 

as specified in §146.82 (a)(12), that demonstrate that the well, as constructed, will prevent 

unacceptable fluid movement; allow the use of appropriate testing devices and workover tools; 

and allow continuous monitoring of the annulus space between the injection tubing and longstring casing, as specified in §146.86(a). The Director will evaluate the procedures in the context 

of other data about the site. See the discussion of Class VI well construction requirements in the 

preamble to the final GS rule for additional information. Additionally, EPA is developing 

guidance on the construction of Class VI wells. This guidance will be available on EPA’s 

website at http://water.epa.gov/type/groundwater/uic/wells_sequestration.cfm. 

Letter ID: 0270 Comment ID: 22887 Letter Lines: 72 to 79 

Comment Code: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) 

Comment: 146.87 Logging, Sampling, and Testing prior to Injection well Operation. 

(b) This rule states that the Director may accept cores from nearby wells if the 

owner or operator can demonstrate that core retrieval is not possible and that such 

cores are representative of conditions at the well. The problem is that cores from 

2
nearby wells may not be indicative of the conditions at the well being 

constructed. If possible a down-hole video should be made to accurately show the 

conditions at the well site. 

Individual Response: EPA clarifies that §146.87(b) allows information on cores from nearby 

wells to be submitted only if the operator can demonstrate that core retrieval is not possible and 

that cores from nearby wells are representative of conditions at the Class VI well. If the Director 

approves the use of alternate cores and determines that additional logs, such as video logs, are 

necessary to evaluate the site, he/she has authority under §146.87(a)(5) to require additional 

information. 

Letter ID: 0270 Comment ID: 22888 Letter Lines: 81 to 85 

Comment Code: 1220 1.1.1.1 Terminology and definitions 

Comment Code: 4500 2.5 Proposed Mechanical Integrity Testing (MIT) Requirements (40 CFR 

146.89) 

Comment: 146.89 Mechanical Integrity. 

This rule uses the term "significant" in a number of places when describing 

leaks. There should be either a definition of "significant" or the wells should 

be adequately sealed so that there are no leaks. 

Individual Response: A properly designed and operated well should have no leakage in the 

casing, tubing, or packer and no fluid movement into a USDW through channels adjacent to the 

wellbore. While the intent of MITs is to detect these types of problems as early as possible, the 

goal of the well design and construction requirements at §146.86 is the complete absence of such 

problems. EPA clarifies that the purpose of the "significant leakage" language in this narrow 

context is simply to avoid triggering corrective actions for essentially de minimis situations. 

Determining whether a MIT result should trigger follow-up action is necessarily a case and sitespecific situation; as a result, EPA does not believe it is appropriate to define the term 

"significant leakage" in the context of MITs. In addition, EPA has not defined this term for 

purposes of other injection well classes and this has not been shown to hinder permitting 

authorities' and owners or operators' ability to assess whether injection wells have adequate 

mechanical integrity. EPA believes that this approach allows states flexibility, will not interfere 

with the implementation of existing UIC programs, and maintains protection of USDWs from 

endangerment. 

In keeping with its adaptive rulemaking approach, the Agency plans to collect and review data 

every six years on early GS projects, including MIT data, to determine whether the appropriate 

amount and types of information and appropriate documentation are being collected, and to 

determine if modifications to the requirements are appropriate or necessary. For additional 

information, please see the discussion of MITs in the final rule preamble. 

3
Letter ID: 0270 Comment ID: 22889 Letter Lines: 87 to 91 

Comment Code: 4630 2.6.3 Corrosion monitoring 

Comment: 146.90 Testing and Monitoring Requirements. 

(c) We support extensive corrosion monitoring and control, at least until 

collectively we know more about how cement will react to long-term contact with 

CO2. 

Individual Response: EPA agrees that corrosion monitoring is appropriate given the potentially 

corrosive nature of the CO2 stream. CO2 in the presence of water becomes acidic, potentially 

accelerating corrosion of well materials. The CO2 stream for a GS project may also contain 

small volumes of impurities that could contribute to corrosion. For these reasons, the final rule 

requires quarterly corrosion monitoring at §146.90(c). 

Letter ID: 0270 Comment ID: 22890 Letter Lines: 93 to 103 

Comment Code: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 

146.92) 

Comment: 146.92 Injection Well Plugging. 

The rules describe plugs as a way to abandon class VI wells. 

In order to ensure that these wells are properly abandoned and that they don't 

become a health hazard or a health threat in the future the abandonment of class VI 

wells should consist of completely filling them from the bottom up to land surface 

with an approved sealant (i.e. cement). This assumes that the well was properly 

constructed in the first place. If the well wasn't constructed properly in the 

first place then another abandonment method maybe necessary to properly protect 

the groundwater resource. 

Individual Response: EPA requires that, to protect USDWs from endangerment, injection wells 

must be plugged in a manner to ensure that the well will not serve as a conduit for future fluid 

movement into USDWs. This may be accomplished in a number of ways using a number of 

different types of materials. In the case of GS wells, the plugging materials must be compatible 

with CO2. 

EPA disagrees that Class VI wells need to be completely filled from the bottom of the well to the 

land surface with an approved cement in order to protect USDWs from endangerment. Most 

experts agree that a series of plugs separated by adequate well bore fluid (e.g., drilling mud) is 

considered to be adequate protection, and that the time and expense of continuous cementing 

may not be practical or necessary to prevent fluid migration and in some cases, other methods 

are equally protective. (Source: Technical Assistance Document: Cementing for the Plugging 

and Abandonment of Injection Wells, 1989) The Class VI well plugging requirements at §146.92 

4
are very similar to those for Class I wells, with additional considerations that the materials used 

are compatible with CO2. 

EPA adds that the Director must approve the owner or operator's injection well plugging plan. 

Additionally, while EPA believes the requirements for well plugging are adequately protective of 

USDWs, if there is reason to believe that completely filling the well is necessary to protect 

USDWs from endangerment, nothing in the federal regulation precludes this. 

Letter ID: 0270 Comment ID: 22891 Letter Lines: 105 to 106 

Comment Code: 5300 2.8.3 Site closure activities (40 CFR 146.93) 

Comment: 146.93 Post-Injection Site Care and Site Closure. 

(e) We ask that the site closure reports be posted on-line. 

Individual Response: EPA disagrees that the owner or operator should not be responsible for 

record retention such as site closure reports. EPA believes that the requirements that the owner or 

operator retain for ten years following site closure, records collected during the post-injection 

site care period at §146.93(f) and §146.93(h) are appropriate for the post-injection and site 

closure period to ensure that data are available to support non-endangerment demonstrations and 

to address any concerns that may arise following site closure. This data will also support EPA's 

review of project data as part of the adaptive rulemaking approach. 

In response to the suggestion that the site closure reports be posted on-line, this information 

would be part of the administrative record on the site, and specific options for access to those 

records would be the decision of the permitting authority. 

5