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.
BP Alternative Energy International Limited, a company registered in England and Wales with the company number 1553681, VAT number GB 243 5105 93 and whose registered office is 

Chertsey Road, Sunbury on Thames, Middlesex, TW16 7BP. 

BP Alternative Energy Holdings Limited, a company registered in England and Wales with the company number 2515099, VAT number GB 243 5105 93 and whose registered office is 

Chertsey Road, Sunbury on Thames, Middlesex, TW16 7BP 

BP Alternative Energy Comments to EPA Proposed Rule 

By Mr. Iain Wright 

Well Design, Monitoring and Timeframe for Site Closure 

EPA Public Hearing, Chicago, Illinois – September 30, 20008 

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

INTRODUCTION

• Thank you for the opportunity to speak today. My name is Iain Wright. I work for BP 

and I manage the industrial-scale CO2 geo-sequestration project at In Salah in Algeria. 

BP appreciates EPA's efforts to create a regulatory framework for industrial-scale CO2

geo-sequestration in the US. 

• At In Salah, BP and its partners (Sonatrach and StatoilHydro) have, for the last four 

years, been sequestering around 1 million tonnes/year CO2 in a deep saline formation, 

which is down-dip of a producing gas field. CO2 storage at In Salah is permitted under 

Algerian hydrocarbon regulations and we have learned a number of lessons that could 

be beneficial for the development of geo-sequestration regulations in the US. 

• My comments will address three issues: 

1. Well Design, 

2. Monitoring and 

3. The Timeframe for Site Closure 

WELL DESIGN

• So firstly, Well Design. At In Salah, 1mmtpa CO2 is being sequestered in a formation 

that is 6,000ft deep, 60ft thick and has permeability of only 10mD - very similar to 

many deep saline formations here in the US Mid-west. To do this, we need only three 

wells, but they have very long horizontal sections in the storage formation – in fact, 

they are about as long as they are deep. We recommend that EPA’s regulations 

permit geo-sequestration using horizontal wells. 

• At In Salah, a few miles up-dip from the three CO2 injectors, we have four wells that 

produce natural gas from the same geological formation. The design of the CO2

injectors is identical to the design of the gas producers except that the gas producers 

have stainless steel tubing, whereas the CO2 injectors have conventional mild steel 

(L80) tubing. This is because the gas producers are actually in a more corrosive 

environment than the CO2 injectors. So, just to emphasize that point: the CO2

sequestration wells, permitted at In Salah are constructed to a lower specification than 

the natural gas wells in the same formation. We recommend that the design and 

construction of geo-sequestration wells should be site-specific and fit for the 

purpose of preventing endangerment of USDWs.
BP Alternative Energy Comments to EPA Proposed Rule 

By Mr. Iain Wright 

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

Page 2

MONITORING

• Moving on to my second point: Monitoring. Monitoring is important, but there is a 

common mis-perception that if you want secure storage, you need to do lots of 

monitoring. Well, the UN says that “the proportion of CO2 retained by appropriately 

selected and managed sites is likely to exceed 99% over 1,000 years”. So the key to 

secure storage is the appropriate selection and management of the site. If that is 

done properly, the site will be very secure and the need for monitoring can be 

appropriately reduced. Monitoring is like the speedometer on your car. It does 

contribute to your safety, but more important is the design of the car, the road and how 

you drive the car. 

• Having said that, at In Salah, we are doing a big research project into monitoring, so 

the program is much more extensive than would be appropriate for a commercial 

project. We are trying out new technologies (such as satellite imagery, micro-seismic), 

so that we can see how they perform against conventional oilfield monitoring 

technologies (such as tracers and conventional seismic). 

• But as you can probably hear from my accent, I’m a Scotsman, and Scotsmen don’t 

like to waste money, so every technology that we use at in Salah has been carefully 

chosen to represent good value for money. Before we started injection at In Salah, we 

did a site-specific assessment of leakage risk and then we tailored the monitoring 

program to address those risks. Mandating any specific monitoring technology could 

waste a great deal of money and resources without contributing to the protection of 

USDWs. So we would caution against a universal mandate for any specific 

monitoring technology.

• Many of you will have heard of the other two monitored, industrial-scale CO2 injection 

projects in the world, at Sleipner and Weyburn. If you compare the monitoring activities 

at these sites, you can see that something which works well in one location, may not 

work at all in another location. We encourage EPA to use risk-assessed, 

performance-based criteria to determine site-specific monitoring programs. 

TIMEFRAME FOR SITE CLOSURE

• My third and final point concerns the appropriate timeframe for site closure. There is 

no rational basis to mandate a universal, 50-year minimum timeframe for post-injection 

site care. Such a mandate would kill-off commercial investment in geo-sequestration 

projects. Worse than that, it would preferentially kill-off the best sites – those with 

proven seals and the lowest risk of leakage - oil and gas fields. 

• As the EPA proposal states “the actual time for CO2 plume stabilization will be very 

site-specific”. A well-selected and managed sequestration site (such as an oil or gas 

field) that has met its performance objectives (including plume stabilization) will be 
BP Alternative Energy Comments to EPA Proposed Rule 

By Mr. Iain Wright 

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

Page 3

much more secure and could be closed quickly (say a couple of years). However, (as 

EPA’s cited examples show), CO2 injected in a poorly-confined deep saline formation 

could move around for quite a while such that the closure period will have to wait on 

residual and solubility trapping, and hence, a closure period of several years could be 

more appropriate. We recommend that EPA does not mandate any fixed 

timeframe for site closure. Better would be a site-specific assessment that is 

risk and performance based. 

Thank you 
Letter ID: 0118 

Commenter: Iain Wright 

Organization: BP Alternative Energy 

Letter ID: 0118 Comment ID: 22064 Letter Lines: 17 to 35 

Comment Code: 1320 1.1.3 General comments about GS 

Comment: Thank you for the opportunity to speak today. My name is Iain Wright. I work for 

BP and I manage the industrial-scale CO2 geo-sequestration project at In Salah 

in Algeria. BP appreciates EPA's efforts to create a regulatory framework for 

industrial-scale CO2 geo-sequestration in the US. 

At In Salah, BP and its partners (Sonatrach and StatoilHydro) have, for the last 

four years, been sequestering around 1 million tonnes/year CO2 in a deep saline 

formation, which is down-dip of a producing gas field. CO2 storage at In Salah 

is permitted under Algerian hydrocarbon regulations and we have learned a number 

of lessons that could be beneficial for the development of geo-sequestration 

regulations in the US. 

My comments will address three issues: 

1. Well Design, 

2. Monitoring and 

3. The Timeframe for Site Closure 

Individual Response: EPA acknowledges the comment. Please see the remainder of EPA’s 

responses to this comment for further details. For additional information on EPA’s final 

regulatory approach (including well construction requirements, monitoring, and post-injection 

site care and closure), please see the final rule and preamble as well as the rulemaking docket. 

Letter ID: 0118 Comment ID: 22065 Letter Lines: 39 to 45 

Comment Code: 3840 2.3.2 Horizontal well drilling techniques (seeking comment) 

Comment: So firstly, Well Design. At In Salah, 1mmtpa CO2 is being sequestered in a 

formation that is 6,000ft deep, 60ft thick and has permeability of only 10mD - 

very similar to many deep saline formations here in the US Mid-west. To do this, 

we need only three wells, but they have very long horizontal sections in the 

storage formation - in fact, they are about as long as they are deep. WE 

RECOMMEND THAT EPA’S REGULATIONS PERMIT GEO-SEQUESTRATION USING 

HORIZONTAL 

WELLS. 

1
Individual Response: In the final rule, EPA allows the use of horizontal wells at GS projects. In 

the proposed rule, EPA sought comment on the appropriateness of horizontal drilling techniques 

for Class VI wells, and commenters representing energy companies, electric utilities, the oil and 

gas industry, CCS associations, states, and the public, unanimously supported the concept and 

provided many reasons why horizontal wells could be beneficial at GS sites. Based on an 

evaluation of these comments and additional research by EPA, the Agency has concluded that 

horizontal wells that are properly constructed, logged, and tested for mechanical integrity (i.e., to 

meet the requirements of the GS rule) can ensure the protection of USDWs from endangerment. 

Letter ID: 0118 Comment ID: 22066 Letter Lines: 47 to 57 

Comment Code: 3800 2.3 Proposed Injection Well Construction Requirements (40 CFR 

146.86) 

Comment Code: 3862 2.3.3.1 Use of corrosion-resistant construction materials (seeking 

comment) 

Comment: At In Salah, a few miles up-dip from the three CO2 injectors, we have four wells 

that produce natural gas from the same geological formation. The design of the 

CO2 injectors is identical to the design of the gas producers except that the 

gas producers have stainless steel tubing, whereas the CO2 injectors have 

conventional mild steel (L80) tubing. This is because the gas producers are 

actually in a more corrosive environment than the CO2 injectors. So, just to 

emphasize that point: the CO2 sequestration wells, permitted at In Salah are 

constructed to a lower specification than the natural gas wells in the same 

formation. WE RECOMMEND THAT THE DESIGN AND CONSTRUCTION OF GEOSEQUESTRATION 

WELLS SHOULD BE SITE-SPECIFIC AND FIT FOR THE PURPOSE OF PREVENTING 

ENDANGERMENT 

OF USDWS. 

Individual Response: EPA recognizes that each GS project will be unique and, for this reason, 

the rule provides flexibility regarding appropriate materials for Class VI wells. The rule does not 

specify materials to be used; rather, it provides owners or operators with the flexibility to choose, 

as long as the materials used in Class VI wells are compatible with fluids with which they may 

come into contact and meet or exceed standards developed for such materials by API or ASTM 

International, or comparable standards approved by the Director, as provided at §146.86(b)(1). 

The Director will evaluate the owner or operator's proposed construction procedures, including 

materials to be used, in the context of information about the well, the CO2 stream, and the site, 

as specified in §146.86(b)(1). EPA is aware of GS efforts at In Salah and clarifies that the wells 

in question were not constructed in accordance with U.S. regulations, so the comparison is not 

necessarily analogous. A paper summarizing EPA's review of In Salah and other large 

international GS projects is in the rulemaking docket. 

2
Letter ID: 0118 Comment ID: 22067 Letter Lines: 59 to 92 

Comment Code: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 

CFR 146.90) 

Comment Code: 4655 2.6.5.1 Plume tracking techniques/geophysical methods (seeking 

comment) 

Comment: MONITORING 

Moving on to my second point: Monitoring. Monitoring is important, but there is 

a common mis-perception that if you want secure storage, you need to do lots of 

monitoring. Well, the UN says that "the proportion of CO2 retained by 

appropriately selected and managed sites is likely to exceed 99% over 1,000 

years". SO THE KEY TO SECURE STORAGE IS THE APPROPRIATE SELECTION AND 

MANAGEMENT 

OF THE SITE. If that is done properly, the site will be very secure and the need 

for monitoring can be appropriately reduced. Monitoring is like the speedometer 

on your car. It does contribute to your safety, but more important is the design 

of the car, the road and how you drive the car. 

Having said that, at In Salah, we are doing a big research project into 

monitoring, so the program is much more extensive than would be appropriate for 

a commercial project. We are trying out new technologies (such as satellite 

imagery, micro-seismic), so that we can see how they perform against 

conventional oilfield monitoring technologies (such as tracers and conventional 

seismic). 

But as you can probably hear from my accent, I’m a Scotsman, and Scotsmen don’t 

like to waste money, so every technology that we use at in Salah has been 

carefully chosen to represent good value for money. Before we started injection 

at In Salah, we did a site-specific assessment of leakage risk and then we 

tailored the monitoring program to address those risks. Mandating any specific 

monitoring technology could waste a great deal of money and resources without 

contributing to the protection of USDWs. SO WE WOULD CAUTION AGAINST A 

UNIVERSAL 

MANDATE FOR ANY SPECIFIC MONITORING TECHNOLOGY. 

Many of you will have heard of the other two monitored, industrial-scale CO2 

injection projects in the world, at Sleipner and Weyburn. If you compare the 

monitoring activities at these sites, you can see that something which works 

well in one location, may not work at all in another location. WE ENCOURAGE EPA 

TO USE RISK-ASSESSED, PERFORMANCE-BASED CRITERIA TO DETERMINE SITESPECIFIC 

MONITORING PROGRAMS. 

Individual Response: EPA agrees with commenters and believes that flexibility is important in 

3
developing and implementing a monitoring plan that is appropriately tailored for a specific GS 

site. The purpose of the requirement at §146.90 to develop site-specific testing and monitoring 

plans is to ensure that the monitoring performed at a site is appropriate for site operational 

conditions and the geologic setting. EPA believes that this is the best approach for addressing 

potential risks at GS sites. These flexible provisions in the monitoring requirements for Class VI 

wells enable the owner or operator to tailor monitoring programs to the specific needs of each 

project in consultation with the Director. 

The final regulation provides for flexibility in: 1) methodologies used to collect these data, 2) the 

spatial resolution at which the data should be collected, and 3) how often the data should be 

collected. The number and placement of monitoring wells will be based on site-specific 

information such as the calculated AoR, injection rate and volume, site geology, baseline data, 

and the presence of artificial penetrations within the AoR. In some instances, there may be a 

limited number of options for complying with EPA's minimum requirements. For example, 

monitoring for geochemical changes will require use of monitoring wells and collection of 

groundwater samples for chemical analysis. Many options currently exist for complying with 

other requirements, such as tracking the position of the plume and pressure front within the 

injection zone. 

Flexibility is also provided regarding how to monitor for the specific data required by the final 

rule. The testing and monitoring plan is developed by the owner or operator in consultation with 

the Director and is designed to ensure that a detailed, Director-approved document describing 

how monitoring will be conducted during the lifetime of the project exists. 

EPA also agrees that good site selection and management are crucial elements of a successful GS 

project, but disagrees that this is an effective substitute for rigorous site monitoring. 

EPA does not believe that prescribing specific technologies to be used in all cases for GS would 

be appropriate given the variability in sites. Rather EPA is developing guidance on testing and 

monitoring to assist owners or operators and Directors in evaluating requirements under §146.90, 

including proposed monitoring plans. The guidance describes available technologies and 

recommended approaches for implementing a testing and monitoring plan, including preoperational geophysical logging and testing of injection wells, MITs, injection well testing 

during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, 

and soil gas and surface air monitoring which may be required by the UIC Director for specific 

GS projects. The guidance can be found on EPA’s website at 

http://water.epa.gov/type/groundwater/uic/wells_sequestration.cfm. In addition, in January 2009, 

DOE published a best practices manual entitled "Monitoring, Verification, and Accounting of 

CO2 Stored in Deep Geologic Formations" (DOE/NETL-311/081508); this manual is included in 

the docket for the final GS rule. 

Letter ID: 0118 Comment ID: 22068 Letter Lines: 96 to 112 

Comment Code: 5240 2.8.2.2 Post injection timeframe (seeking comment) 

Comment: My third and final point concerns the appropriate timeframe for site closure. 

4
5

There is no rational basis to mandate a universal, 50-year minimum timeframe for 

post-injection site care. Such a mandate would kill-off commercial investment in 

geo-sequestration projects. Worse than that, it would preferentially kill-off 

the best sites - those with proven seals and the lowest risk of leakage - oil 

and gas fields. 

As the EPA proposal states - the actual time for CO2 plume stabilization will be 

very "site-specific". A well-selected and managed sequestration site (such as an 

oil or gas field) that has met its performance objectives (including plume 

stabilization) will be much more secure and could be closed quickly (say a 

couple of years). However, (as EPA’s cited examples show), CO2 injected in a 

poorly-confined deep saline formation could move around for quite a while such 

that the closure period will have to wait on residual and solubility trapping, 

and hence, a closure period of several years could be more appropriate. WE 

RECOMMEND THAT EPA DOES NOT MANDATE ANY FIXED TIMEFRAME FOR SITE 

CLOSURE. BETTER 

WOULD BE A SITE-SPECIFIC ASSESSMENT THAT IS RISK AND PERFORMANCE 

BASED. 

Individual Response: EPA agrees that there will be circumstances where it can be demonstrated 

in less than 50 years that the plume and pressure front no longer pose a risk of endangerment to 

USDWs. For this reason, the final GS rule offers owners or operators flexibility regarding the 

duration of the PISC timeframe by: (1) allowing the Director discretion to shorten or lengthen 

the PISC timeframe during the PISC period based on site-specific data, pursuant to requirements 

at §146.93(b); or (2) affording the Director discretion to allow a Class VI well owner or operator 

to demonstrate, based on substantial data during the permitting process, that an alternative PISC 

timeframe may be appropriate if it ensures non-endangerment of USDWs pursuant to 

requirements at §146.93(c). 

EPA believes that a default post-injection site care timeframe of 50 years, with flexibility to 

adjust the timeframe for a limited number of GS projects during the permitting process where 

substantial data exists to demonstrate that an alternative timeframe would be protective of 

USDWs, or based on data collected during the PISC period, is appropriate to address the range of 

sites where GS is anticipated to occur, to accommodate site-specific circumstances and various 

geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. 

Both approaches will utilize site-specific data, and be based on pressure monitoring and USDW 

impacts. 

EPA adds that the purpose of the GS rule is not to incentivize the use of GS; rather, the purpose 

of the GS rule is to ensure that, where GS is deployed, it is conducted in a manner that protects 

USDWs from endangerment.