UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION 5 

77 WEST JACKSON BOULEVARD 

CHICAGO, IL 60604-3590 

JIIOV J. 4 2Q13 REPLY TO THE ATTENTION OF: 

CERTIFIED MAIL 7001 0320 0005 8923 4123 

RETURN RECEIPT REQUESTED 

Kenneth K. Hmphreys 

Chief Executive Officer 

FutureGen Industrial Alliance, Inc. 

73 Central Park Plaza East 

Jacksonville, Illinois 62650 

WU-16J 

Subject: Request for Additional Information Regarding FutureGen 2.0 Wells, United 

States Environmental Protection Agency Underground Injection Control (UIC) 

Permit Applications for Four Geologic Sequestration Wells; United States 

Environmental Protection Agency UIC Permit Nos. IL-137-6A-0001, -0002, 

-0003, & -0004 

Dear Mr. Humphreys: 

In order to complete our review ofFutureGen's permit applications, we need additional 

information described in the enclosure with this letter. Please submit any information no later 

than 3 0 days from the receipt of this letter. 

Inquiries concerning the contents of the enclosure may be directed to Jeffrey McDonald of my 

staff by telephone at (312) 353-6288 or by email to mcdonald.jeffrey@epa.gov. 

cc: Stephen Nightingale, IEP A 

Enclosure 
Requests based on the text application 

Section Section Title Request 

Number 

3.1.2 Physical Processes Modeled Page 3.3 of the permit application states that laboratory 

investigations for quantifying the importance of chemical 

reactions are being conducted. Are any results available? 

Modeling considering reactive transport may need to be 

conducted ifthe lab results indicate significant iron carbonate 

precipitation that changes injection zone porosity. 

3.1.3.2 h1trinsic permeability in the A "curve permKCal" is referenced, but the location of the 

h1jection Zone curve isn't clear. Please provide a copy or further explain. 

3.1.3.2 Intrinsic penneability in the No hydrologic tests were conducted in tl1e Elmhurst 

illjection Zone fonnation to measure a Permeability-Thickness Product and 

no ELAN calculation was given. How was a PenneabilityThickness Product detennined for the Elmhurst fonnation? 

3.1.3.2 Vertical Penneability Kv/Kh measured in 20 core plug pairs; highly related to 

presence of mudstone/shale; sparse data led to use of 

literature values. Given that 20 ratios were successfully 

determined, how do they compare to the literature values? 

3.1.3.2 Capillary Pressure and Data was used from the Manlove field to generate BrooksSaturation Fnnctions Corey parameters for four different permeability ranges, 

shown in Table 3.5. Please provide a citation for this 

information. 

3.1.3.3 Temperature We believe 6.72"3 should be 6.72 X 10"3 °F/ft? 

3.1.3.3 Temperature Why is regression used rather tl1an measured data? 

3.1.5 Representative Case Scenario Section 3.1.5 of the permit application notes that the design of 

Description the injection wells was chosen to "avoid sensitive areas" (p. 

3 .26). What are these "sensitive areas" and how were they 

identified? Is tl1is the reason the horizontal well legs are not 

evenly distributed in a radial fashion? 

3.1.6 Computational Model Results It would be helpful to have a verbal description of the 

changes between figures in a series: e.g., the 70yr figure in 

3 .21 has a wide area in green but tl1e other tllree do not: what 

does this tell us? It is extremely difficult to judge scale from 

these figures. Please provide dinlensions of plume and 

pressure front over time, together. A map view, such as Fig. 

3.25, would be ideal. What is the largest extent of the plume 

and when does this occur? Because these figures are not all 

at the same scale, they are hard to compare. 

3.1.6 Computational Model Results Please provide figures beyond year 70. We suggest figures to 

year 100. 

3.1.10 Parameter Sensitivity and 32 cases were defined using "quasi Monte Carlo" approach. 

Uncertainty This approach should be described and possibly cited. 

3.1.10 Parameter Sensitivity and The pennit application states that 32 cases were defined from 

Uncertainty the representative case model. The parameter values used for 

these 32 cases should be presented in a table. 
Requests based on the online GS data tool modeling input 

Tab Request 

Model Domain In the permit application and the Input Advisor submission, subsurface locations 

are referred to both in terms of depth (with respect to the ground surface or the 

kelly bushing) and elevation (with respect to sea level). For example, the top ofthe 

open interval is described as 3,850 ft below ground surface on p. 3.26 of the permit 

application, while the Input Advisor submission refers to this location as having an 

elevation of -3,220 ft. Is it correct to asswne that all of the Z coordinate values 

submitted in the Input Advisor represent elevations relative to sea level and are 

consistent (e.g., z coordinates provided for well intervals)? 

Rock Properties The saturation function/relative permeability spreadsheet submitted via the h1put 

Advisor defines the Brooks-Corey function for the relative permeability and 

satmation functions and provides corresponding parameters for different layers. It 

would be helpful if the functional fonns of Brooks-Corey for the relative 

permeability and saturation functions were also provided in the spreadsheet 

Rock Properties Horizontal intrinsic permeabilities of the confining zones (seep. 3.7 of the permit 

application). Because ofthe reliability issues associated with ELAN log-derived 

permeabilities below a certain limit (0.01 mD), FutmeGen used the horizontal 

Klinkenberg permeabilities for each model layer. Was there any correction applied 

to the Klinkenberg penneabilities used for the confining zone layers, particularly 

because these may represent tight porous formations? 

Rock Properties Residual saturation. As shown in the "Sat-function-rei-perm" spreadsheet, residual 

aqueous saturation values used in the FutmeGen AoR model range from 0.0597 to 

0.0810. Residual aqueous satmation values found in the literatme for the Mt 

Simon Sandstone range from approximately 0.2 to OA (Zhou et aL, 2010; Bandilla 

et aL, 2012b; Krevor et aL, 2012; Matthias et aL, 2013). It is expected that sitespecific capillary pressure and residual aqueous satmation data for the FutmeGen 

site will be generated after pre-injection testing of the proposed wells. However, an 

explanation of the effects of this selection on plume and pressure-front 

development may need to be provided. 

Model Output Surface flux. For the flux output files, two areas ( 4 mix 4 mi and 8 mix 8 mi) were 

selected and fluxes were defined across the east, west, north, and south boundaries 

of both of those areas, as well as the top of the Franconia and the top of the 

Proviso. What are the i, j, k indexes that define the 4 mix 4 mi and 8 mix 8 mi 

areas? 

AoR Pressure Front Critical pressure calculation. As mentioned in the previous Request for Additional 

Delineation hlionnation from EPA, it is recommended that FutmeGen explores altemative 

methods as well for the critical pressure determination, such as such as those 

described by Nicolet aL (2008) Birkholzer et aL (2011 ); orBandilla et aL (2012). 

AoR Pressure Front Pressure differential/simulation time. Despite not calculating a critical pressure 

Delineation with respect to the lowermost USDW, FutmeGen did apply a pressure differential 

of 31.45 psi to determine sinmlation tinles-this value is described as "the pressure 

differential needed to force fluids from the injection zone into the surficial alluvial 

aquifer system through a hypothetical conduit" (p. 3.25). In other words, it was not 

calculated with respect to the lowermost USDW, but rather the aquifer currently in 

use as a drinking water source. The footprint of this pressme front indicates a 

larger area that may be impacted by injection compared to the footprint of the 

separate-phase plume. FutnreGen acknowledged this pressure effect when 

identifying artificial penetrations and evaluated two wells that penetrate the Mt. 
Simon outside of the delineated AoR, about 16 mi south-southwest of the proposed 

storage site, noting "Although these wells are well outside the AoR, they are within 

the region where increased pressures in the injection zone are expected and were 

therefore considered for additional review" (p. 3.43).What calculations were used 

to determine this value of 31.45 psi? 

AoR Pressure Front Temperature in St. Peter (WWW). Is 73°F, determined at the subsea elevation ofDelineation 1,129 ft, measured at the stratigraphic well (API# 12-137-22132-00)? This value 

does not match the resulting temperature for this elevation based on the linearregression relationship given in Figure 3.13 -which indicates a temperature of 

about 82°F at a depth of 1,762.96 bkb (-1,129 ft subsea elevation). 

Suggested References: 

Bandilla, K.W., S.R. Kraemer and J.T. Birkholzer. 2012a. Using semi-analytic solutions to 

approximate the area of potential impact for carbon dioxide injection. International 

Journal of Greenhouse Gas Control 8: 196-204. 

Birkholzer, J.T., Q. Zhou, A. Curtis and S. Finsterle. 2011. A sensitivity study on regional 

pressure buildup from large-scale C02 storage projects. 1Oth International Conference on 

Greenhouse Gas Control Teclmologies, 19-23 September 2010, Amsterdam. Energy 

Procedia 4(2011): 4371-4378. 

Nicot, J.-P., C.M. Oldenburg, S.L. Bryant and S.D. Hovorka. 2008. Pressure perturbations from 

geologic carbon sequestration: Area-of-review boundaries and borehole leakage driving 

forces. 9th International Conference on Greenhouse Gas Control Teclmologies, 16-20 

November 2008, Washington, D.C.