Atmospheric and soil-gas monitoring for surface leakage at the Michigan Basin CO2 pilot test site in Ostego Co., Michigan, using a perfluorocarbon Tracer Art Wells, … Tom Wilson… ? Tentative outline Abstract Introduction Background Characterization of Near-Surface Geology at the Site Surface Geochemical Evidence of Leakage in the Area Well Integrity and the History of Well Leakage at the Site Monitoring Grid Design Analysis and Sampling Protocol Tracer Injection Results and Conclusions from Tracer Monitoring Conclusions: References Preliminary rough outline f revision/input/comment fro co-authors Abstract (to be revised) Evaluation of the near-surface geology at the MRCSP’s Ostego Co., Michigan CO2 Pilot site reveals the presence of about 600 feet of glacial till covering lower Mississippian and upper Devonian shale intervals that includes the Antrim Shale. The injection zone is in the Bass Island Group approximately 4500 feet beneath the surface. The Antrim is an organic rich fractured Devonian Shale reservoir. Any CO2 entering the Antrim would likely migrate upward through extensive fracture systems in this reservoir. Leakage is known to occur in the area. Geochemical sampling reveals anomalies over Niagaran reef trends to the southwest. Hydrocarbon microseepage tends to be absent in produced areas. A study conducted in the vicinity of the pilot site by Toelle et al. (2007) revealed that a prevalent source of leakage in the area is associated with corroded well casing. The Niagaran reef in the area of the injection well was inadvertently water flooded by migration of water disposal from the shallow Dundee Formation along corroded well casing. The water flooding was extensive and terminated production in from the reef in some wells. Recommendations for additional sampling were based primarily on the results of the study presented by Toelle et al. (2007), but also included consideration of the regional fracture systems and local structural dip. Introduction Art, can you and others describe development of NETL tracer and soil gas testing methodologies and results obtained from previous pilot efforts? Note other competing methodologies and the relative merits of your methods. Describe relationship with the MRCSP. Note injection zone and complimentary monitoring undertaken by the MRCSP: any water wells sampling from the top of the primary seal (?); soil CO2 & CH4 flux, ….(?). 1 Background Characterization of Near-Surface Geology at the Site A background geological characterization effort was conducted at the Michigan Basin pilot site to provide some perspectives and insights into the potential for leakage of injected CO2. Initially, we examined the near-surface geology in an approximately 7 square mile area surrounding the pilot site in Ostego Co., Michigan. This initial evaluation provided a look at the subsurface geology down to the level of the Antrim “Dark” Shale. The Antrim is a Devonian shale equivalent to the Devonian shale of the Appalachian Basin. The Antrim is a pervasive gas producer throughout the Michigan basin. A relatively large number of wells with information on this shallow zone (approximately 70) were available in the area. Very few deep wells were available. Most of the wells were completed in the Antrim Shale. The surface is covered by a layer of glacial till between 500 and 600 feet thick (Figure 1). The till thins to the north of the injection well and is locally thicker beneath the injection well. Figure 1: Thickness of glacial cover in the region. The injection well is located roughly in the center of grid of CATS near the southwest corner of the middle section (Section 30) in this map. The depth to the till/bedrock interface at the injection well is about 640 feet. The stratigraphic column for the basin (Figure 2) shows the relative positions of strata in the sequence overlying 2 the injection zone in the Bass Island Dolomite. The Bass Island injection zone lies at a depth of between 3000 and 3400 feet below sea level in the area of the injection well. The surface elevation at the injection well is 1188 feet above sea level putting the injection zone at a depth of about 4200 to 4600 feet subsurface. The glacial till in this area covers the lower Mississippian Coldwater Shale (Figure 2). The Antrim Shale is separated from the base of the glacial till by an interval of shale including the Sunbury and Bedford shale intervals (Figure 2). Is there a report from Battelle describing the results of the project, site geology and primary seal for the site? The MRCSP never provided any information to us that I’m aware of. We would want to be sure our analysis was complimentary and consistent. The primary sealing strata would appear to be the Bell Shale. Neeraj (2006) refers to the Detroit Group which appears to include the Amhertsburg, Ls, Lucas Ls.,. The Traverse Group (including the Bell Shale?) and Dundee Limestones overlie the Detroit River Group. Dundee Ls and Bell Shale. The USGS (http://tin.er.usgs.gov/geology/state/sgmc-unit.php?unit=MIDdr%3B0) indicates that the Detroit River Group includes the Flat Rock dolomite (40 to 150 feet thick), Anderdon limestone (40 to 50 feet thick), Amherstburg dolomite (20 feet thick), and Lucas dolomite (200 feet thick) members. Would appear to be the equivalent of the Onondaga Ls in NY. Oriskany Ss lies below the Bois Blanc Fm. The Lucas is an oil producer with 15%-30% porosity and low perm (5-25md). 3 From Gupta, N., 2006, MRCSP Ostego County Site: Geologic field tests in the Michigan Basin: DOE/NETL Regional Partnership Annual Meeting, Pittsburgh, PA Figure 2 (possible replacement) …. 4 Figure 2: General stratigraphic column for the Michigan basin area. Depth to base of till in the vicinity of the injection well is approximately 600 feet. The Bass Island lies about 3000 feet below the Antrim Shale Bedrock elevations at the base of the glacial till (Figure 3) are relative to the sea level datum and thus do not include the influence of variations in topographic relief which are superimposed on the total depth to the base of the till shown in Figure 1. On this sea-level referenced view, the pilot well is located over a bedrock high. Groundwater drainage at least at deeper levels within the till will be away from the injection well to the northwest. The regional scale view provided by maps indicates that at the level of the bedrock/till interface, the area surrounding the injection well is in a bedrock low. 5 Figure 3: Elevation variations on the base of the till relative to the sea level datum. The structure on the Antrim Shale (Figure 4) dips gently to the south-southwest in the vicinity of the injection well and in general throughout the surrounding area. There do not appear to be local structures related to faults in the area. Small perturbations in the contours are probably due to variations in the density of well coverage in the vicinity of the injection well. Some anomalous features in the surrounding area have been checked. A few wells in the data base are deviated which leads to some differences in measured versus true vertical depths. 6 Figure 4: Structure on the top of the Antrim Shale. The Antrim Shale is an organic rich shale that produces gas from open fracture systems. As the depth to the top of the Antrim map reveals (Figure 4), this gas reservoir comes to within about 1000 feet of the surface and may contribute to the soil gas anomalies that are pervasive in the basin (Wood et al., 2004a and b). Since the Antrim is a fractured reservoir any CO2 that might make its way up through the strata overlying the Bass Island injection interval will migrate through the fracture systems of the Antrim in the updip, north-northeast direction in this area (Figure 4). The updip direction also brings the unit closer to the surface (Figure 5). 7 The interval separating the base of the till and Antrim is thinnest (about 400 feet thick) to the northwest (Figure 6). The Antrim lies nearest the surface, about 700 feet, in this area (Figure 5). Figure 5: Depth (measured depth) to the top of the Antrim shale. 8 Figure 6: An isopach map of the thickness of the interval between the base of the till and the top of the Antrim Shale. Based on the near surface geology and extensive drilling history at the site our primary concern was that CO2 might possibly migrate out of existing wells in the area. We would expect any CO2 making its way up into the Antrim to migrate updip. However, the dip is slight in the area (just over 100 feet per mile (a little over a degree to the south-southwest). Ryder (2003) indicates that fractures observed in outcrop about 10 to 15 miles north of the pilot site have dominant orientations of N52E and N46W with subordinate sets oriented north-south and east-west. These trends are inferred from approximately 5000 measurements across the northern part of the basin. Ryder (2003) reports that fracture trend remains fairly consistent throughout the area. Ryder (2003) provides a comprehensive summary of the general details of fracture observations and literature review. Observations of more than 600 fractures taken from oriented core reveal consistency with the outcrop observations (Richards, Waters, and others, 1994). The north-northeast rise in the Antrim structure combined with fracture orientation data 9 suggested that areas to the northeast along the N52E fracture trend might be good locations for additional monitoring. If local fracture systems in the Antrim shale control flow of escaped CO2 then additional CATS could be placed in the up dip direction along an azimuth associated with the major systematic fractures noted by Ryder. A secondary location would lie to the northwest of the injection well along the azimuth corresponding to the secondary NW trending fracture set. Surface Geochemical Evidence of Leakage in the Area Extensive geochemical sampling conducted by Wood et al. (2004 a and b) reveal the presence of hydrocarbon seeps associated with Niagaran production. Reefs exhibited propane geochemical anomalies that formed haloes around one reef, with highs surrounding the reef and lows directly above the reef. Pentane anomalies were also observed in some areas. Variable results were obtained in their studies and the reader is referred to the papers by Wood et al. (1004a and b) for the details of their study. Their studies do suggest that light hydrocarbon microseeps are present in the area associated with deeper hydrocarbon reservoirs. These anomalies tend to be absent over produced fields. Their observations suggest the presence of migration pathways facilitating short term migration of light hydrocarbons from the Niagaran reef trend which lies at greater depth than the Bass Island injection zone. Well Integrity and the History of Well Leakage at the Site Site evaluation also incorporated results and observations from an earlier enhanced gas recovery (EGR) operation conducted by Core Energy in the deeper Niagaran reef trend. Schlumberger in a joint effort with Core Energy collected 3D seismic over the reef complex. 3D seismic acquisition was repeated to provide time lapse seismic response resulting from CO2 injection into the reef. Toelle et al. (2007) provides perspectives on well history in the area that are pertinent to possible leakage of CO2 injected in the shallower Bass Island Formation as part of the MRCSP carbon sequestration pilot test. Several wells are noted in the Toelle et al. (2007) study (Figure 8). 10 Figure 8: Structure on the Antrim shale showing the location of key wells in the Toelle et al. (2007) study. 11 Toelle et al. (2007) note that corroded casing is common to all wells in the area. Disposal of produced water in the shallower Dundee Formation helped facilitate degradation of the casing and eventual leakage. Eventual well corrosion caused disposal water injected into the Dundee to drain into deeper intervals. This led to indirect water flooding of the deeper Niagaran reservoir. The 2-30 well (Figure 9, east of the C2-30 well) began to produce water in 1985. A 100% water cut arrived at the C2-30 well, about 20 feet down dip, in 1997. This resulted in the termination of primary production in the field. Appearance of CO2 in the Charlton 1-30 well injected from the end of the C2-30 lateral (Figure 9) indicates a nearly east-west connection between these two points. The Dundee lies above the Bois Blanc injection zone and is considered to be part of the primary sealing intervals in the Detroit River Group (Gupta, 2007). Corroded well casing might facilitate vertical release of injected CO2 through the primary seal. Figure 9: The end of the C2-30 injection lateral extends approximately 800 feet north-northwest of the C2-30 surface location. CO2 injected into the C2-30 migrated into the Charlton 1-30 well. 12 Core Energy injected CO2 into the Niagaran through the deviated C2-30 well and temporarily produced oil from the 1-30 well to the north. The plan was to produce from the 1-30 well until it began cycling unacceptable amounts of CO2. At that point, the 1-30 well would be converted to an injection well with the idea of pushing the remaining oil to the south. The history of the 1-30 included 5 months of water production with no oil. The well began to produce CO2 in the production stream only a month after oil production occurred. Figure 10: Suggestions for additional monitor locations. Based on the history of well corrosion, water dumping and inadvertent flooding of the deeper Niagaran Reef in the area, additional monitors were placed near wells in the surrounding area (Figure 10). Given the history of significant casing corrosion, CATS placements were recommended near wells noted in the study by Toelle et al. (2007). Although at some distance, the presence of well corrosion along with interconnection over a distance of approximately 1 km would make this a good location to monitor. 13 Monitoring Grid Design The tracer and soil-gas monitoring grid consisted of 24 locations in the vicinity of the CO2 injection well. A rectangular grid was employed with spacing between monitors of 100 meters. The grid is pictured below (Figure *). In addition, monitors were placed adjacent to near-by wells to evaluate potential leakage associated with wellbores. Four of the monitors lying off the main grid were also placed to evaluate areas of interest based upon the geological assessment of leakage potential. The tracer-in-soil-gas monitors were ¾ inch steel pipes driven 1 meter into the soil, and into which vial containing sorbent material (62 mg of ambersorb) were placed to collect any tracer contained in the soil-gas exposed by removing the penetrometer head. The tops of the pipes were sealed to prevent entry of atmosphere and ground water. The sorbent vials were exchanged as sets: one set pre-tracer injection, one set during tracer injection, and 4 sets posttracer injection. The quantity of air or soil-gas sampled by passive diffusion into the sorbent vials has been determined to be equivalent to 200 ml/day. A subset of 14 of the soil-gas monitors also contained attached, passive monitors for tracer-inthe-atmosphere. These included monitors associated with wells to evaluate atmospheric tracer plumes that might be generated by leakage from wellbores or from pipes and fittings through which tracer containing gases or liquids were flowing. In addition, sets of active 3 liter air samples were taken during the collection and placement off all pre- and post-injection sorbent sets to detect atmospheric tracer plumes, and to ultimately locate their source if found. The active air samples also provided information on the overall concentration of atmospheric tracer near the site, which could be used to detect area wide tracer microseepage or release of tracer from nearby gas treatment facilities, lines, etc. Analysis and Sampling Protocol Analysis of the sorbent packets was conducted in NETL’s PFC tracer laboratory. The approximately 2 ½ inch long glass vials containing 62 mgs of ambersorb were thermally desorbed to release PFC tracer collected during field exposure. Analysis employed gas chromatography with a chemical ionization/ mass spectrometer detection system. Instrumentation and methodologies were developed specifically to remove typical contaminates found in soil-gas at sequestration test sites near active production areas. The detection limit for tracer is approximately 3 fL tracer / L of soil-gas or air. This detection limit, approaching the part-per-quadrillion level, requires a protocol to prevent cross-contamination of sorbent packets. This protocol includes, among other measures, the physical separation of the tracer injection and monitor placement teams (who were staying in different cities), performing all non-injection syringe pump operations offsite, and sorbent packet exchange procedures. Tracer Injection o On 20 February, 2008, under sunny skies and with temperatures right around 10 F, Hank and Rod set up the syringe pump and transfer lines at the Lower Michigan Basin injection well. 255 ml of PMCH had already been filled into the syringe pump before arriving at the well. A container of about 400 ml of cyclohexane was attached to the pump and the auto refill feature was activated. The pump was set into a tedlar bag containing activated charcoal and the bag carefully brought up over the pump and sealed at the top. One hole was provided through the bag for the 110 VAC power cord and the 1/8” stainless steel transfer line between the pump and the valve on the line carrying CO2 into the well. CO2 injection flow rate was 410 tons/day. 14 At 1410, injection of PMCH was begun at the rate of 350 microliters/minute, i.e. 255 ml over the next 12 hours. Then the pump would automatically refill with cyclohexane and cyclohexane would be pumped through the transfer line and into the well. This cyclohexane flush would serve to clear the lines of residual tracer. After all the settings and valves were double checked we wrapped the apparatus with a blue tarpaulin and rope and left the wellhead area. On 21 February at 0830 Hank and Rod returned to the wellhead and found the CO2 injection flow rate still about 410 tons/day. All 255 ml of PMCH had been injected, but only about 150 ml of the cyclohexane wash had been injected because of the transfer line icing up inside. The tracer (255 ml of perfluoromethylcyclohexane- PMCH) was injected at a constant rate from a syringe pump over 12 hours. Since the detection limit of tracer in soil-gas or in the atmosphere -15 is nearly one part-per-quadrillion (10 v/v), it is inevitable that some atmospheric tracer plume will be released during the tracer injection process. This release was minimized by sealing the syringe pump and it’s fittings in a plastic bag, which also contains activated charcoal. This atmospheric tracer plume was carefully monitored, and its drift noted for comparison to later results. Results and Conclusions from Tracer Monitoring Results for tracer in soil-gas (Table 1) and for tracer in active 3 Liter air samples (Table 3) are given for 1 pre-tracer injection background survey and for 4 post-tracer injection surveys. Results for tracer in passive air samples are given in Table 2, with sorbent set 2 designed to evaluate the atmospheric tracer plume released during tracer injection. It was found that atmospheric levels of tracer exceeded 1,000 fl/L of air at only one site (Table 2). This was a modest plume, and it was concluded that by comparison to past injections, efforts to limit tracer release had been successful. No evidence of barometric pumping of tracer into the soil was found during post-tracer injection surveys. The following results are referenced to the 3 tables below, with pre-injection survey results in the left hand column and an average of the 4 post-injection surveys in the right hand column. Comparisons in Table 1 of the pre-injection soil-gas survey results (bottom of the far left column) to averages of the 4 post-injection surveys (bottom of the far right column) are statistically identical, and give no indication of the leakage of tracer into soil-gas. Results for passive atmospheric monitoring (Table 2) and for active 3 Liter atmospheric monitoring (Table 3) also remained at background levels during the 4 post-injection surveys. Detection levels for tracer in the atmosphere or in soil-gas correspond to approximately a <0.01% leakage rate per year for an injection of this size. Migration of tracer tagged CO2 from the target reservoir into the Antrim shale might result in possible release channels to the surface, including wellbore, microseepage, and releases associated with gas production infrastructure. The latter scenario would raise the overall background levels of atmospheric tracer beyond pre-injection levels. No evidence of leakage or migration was discernable in this study. Conclusions: Geologic characterization of the site reveals the presence of a thick layer of glacial till in the area surrounding the CO2 injection well. The thickness of the glacial till near the injection well is 15 approximately 600 feet. The injection well is located in a bedrock low where till thickness increases to about 640 feet. The till was deposited on the lower Mississippian Coldwater Shale. The upper Devonian shales including the Antrim Shale lie within a few hundred feet of the surface. The Antrim Shale is a tight naturally fractured gas reservoir that lies a few hundred feet below the till. The Antrim is a prolific gas producer in the Michigan Basin. The Antrim rises gently with a dip of about one degree to the northeast across the site. While this dip is quite small, if CO2 were to escape from the injection zone and reach the Antrim it might move through regional fractures systems in the up-dip direction. Geologic characterization of the area did not suggest the presence of any faults. Some early recommendations for additional sample placement were made on the basis of dominant trends in the Antrim natural fracture systems reported by Ryder (2003) and on the local structural dip. Geologic characterization of the site provides the group with several perspectives regarding the potential for CO2 leakage and likely leakage mechanisms. Previous geochemical studies conducted in the area by Wood et al. (2004 a and b) reveal that light hydrocarbon seeps are prevalent in the area. These seeps have been associated with production from the Niagaran reef trend which underlies the Bass Island CO2 injection zone. The presence of these seeps reveals that migration pathways are present in the area and can facilitate rapid migration of light hydrocarbons to the surface from intervals deeper than the CO2 injection zone. Extensive leakage associated with corroded wells in the immediate vicinity of the CO2 injection well was reported in detail by Toelle et al. (2007). Based on their study, additional recommendations were made in direct support of the NETL plan to place samplers near wells close to the CO2 injection well. References Richards, J.A., Walter, L.M., Budai, J.M., and Abriola, L.M., 1994, Large and small scale structural controls on fluid migration in the Antrim Shale, northern Michigan basin, in Advances in Antrim Shale Technology: Gas Research Institute in cooperation with the Michigan section SPE [Mount. Pleasant, Michigan, Dec. 13, 1994], 23 p. Ryder, R.T., 2003, Fracture patterns and their origin in the Upper Devonian Antrim Shale gas reservoir of the Michigan Basin: A review. USGS Open File Report 96-23. Toelle, B., Pekot, L., and Mannes, R., 2007, CO2 EOR from a north Michigan Silurian reef: Procedings paper, Spcietyof Petroleum Engineers SPE-111223-PP, 6p. Wood, J. R, Wylie, A., and Quinlan, W., 2004a, Surface geochemical results complement conventional development approaches: in WorldOil Magazine (WorldOil.com) http://www.worldoil.com/magazine/MAGAZINE_DETAIL.asp?ART_ID=2456&MONT Online Magazine Article Features – Dec-2004, 10 pages. Wood, J. R, Wylie, A., and Quinlan, W., 2004b, Using recent advances in 2DE seismic technology and surface geochemistry to economically redevelop a shallow shelf carbonate reservoir” Vernon Field, Isabella County, MI: DOE Quarterly report, Award number DE-FC2600BC15122, 23p. 16 Figure 1: Tracer monitoring grid is shown on this orthophoto of the site. 17 LMB19 4991200 4991100 LMB01 LMB02 LMB03 LMB04 4991000 LMB08 LMB07 LMB06 LMB05 C3-30A 4990900 LMB09 LMB10 LMB11 LMB12 LMB17 4990800 LMB16 LMB15 LMB14 LMB13 4990700 4990600 LMB18 697700 697800 697900 698000 698100 698200 Figure *: Reference map for monitoring grid. 18 All Values in fl/L SORBENT SET #1 9-28-08, 1022-08, BACKGROUND SORBENT SET #2, During Tracer Injection 2-20-08 SORBENT SET #3, Immediatel y After Tracer Injection, 2-21-08 to 3-12-08 SORBENT SET #4, 3-12-08 to 4-08-08 SORBENT SET #5, 4/8/08 to 5/21/08 SORBENT SET #6, 5/21/08 to 9/17/08 Post injection Averages 8 7 4 7 10 9 7 8 Site LMB-01 LMB-02 9 8 9 LMB-03 LMB-04 LMB-06 LMB-07 LMB-08 LMB-09 2 8 14 10 9 28 20 12 149 10 8 14 10 39 11 9 9 9 8 15 7 2 11 13 7 7 10 9 9 16 11 18 44 8 9 LMB-10 LBM-11 LMB-12 LMB-13 LMB-14 LMB-15 10 12 8 14 36 15 9 12 7 10 12 9 9 11 1 10 11 9 3 12 6 11 9 13 12 9 2 9 13 9 8 11 4 10 11 10 LMB-16 LMB-17 LMB-18 LMB-19 LMB-20 15 6 5 11 6 3 19 36 9 4 3 12 6 3 2 12 2 10 10 5 3 12 9 6 3 12 16 Average Standard deviation Median Max Min 12 7.84 20 32.27 10 7.90 7 4.09 9 2.97 12 8.76 10 36 2 10 149 3 9 39 1 7 15 2 9 13 2 10 44 3 Table 1 Tracer in Soil-Gas: Pre- and Post-Tracer Injection Results 19 4991200 4991200 4991100 LMB01 LMB02 LMB03 LMB04 4991000 LMB08 LMB07 LMB06 LMB05 50 45 40 35 30 25 20 15 10 5 0 C3-30A LMB09 LMB11 LMB10 LMB12 LMB17 4990800 LMB19 LMB19 4991200 4990900 Set 3 Set 3 Set 1 LMB19 LMB16 LMB15 LMB14 LMB13 4990700 4991100 4991000 LMB01 LMB02 LMB03 LMB04 LMB08 LMB07 LMB06 LMB05 C3-30A 4990900 LMB09 LMB10 LMB11 LMB12 LMB17 4990800 LMB15 LMB16 LMB14 LMB13 4990700 4990600 4990600 50 45 40 35 30 25 20 15 10 5 0 4991100 LMB01 LMB02 LMB03 LMB04 4991000 LMB08 LMB07 LMB06 LMB05 C3-30A 4990900 LMB09 LMB10 LMB11 LMB12 4990800 LMB16 LMB15 LMB14 LMB13 LMB17 4990700 4990600 LMB18 LMB18 LMB18 697700 697800 697900 698000 698100 698200 697700 697800 697900 698000 698100 698200 697700 697800 697900 698000 698100 698200 Set 5 Set 4 LMB19 LMB19 4991200 4991200 4991100 LMB01 LMB02 LMB03 LMB04 4991000 LMB08 LMB07 LMB06 LMB05 C3-30A 4990900 LMB09 LMB11 LMB10 LMB12 LMB17 4990800 LMB15 LMB16 LMB14 LMB13 4990700 50 45 40 35 30 25 20 15 10 5 0 4990600 4991100 LMB01 LMB02 LMB03 LMB04 4991000 LMB08 LMB07 LMB06 LMB05 C3-30A 4990900 LMB09 LMB10 LMB11 LMB12 4990800 LMB16 LMB15 LMB14 LMB13 LMB17 4990700 50 45 40 35 30 25 20 15 10 5 0 4990600 LMB18 LMB18 697700 697800 697900 698000 698100 698200 697700 697800 697900 698000 698100 698200 Set 6 Average LMB19 LMB19 4991200 4991200 4991100 LMB01 LMB02 LMB03 LMB04 4991000 LMB08 LMB07 LMB06 LMB05 C3-30A 4990900 LMB09 LMB10 LMB11 LMB12 LMB17 4990800 LMB16 LMB15 LMB14 LMB13 4990700 50 45 40 35 30 25 20 15 10 5 0 4991100 LMB01 LMB02 LMB03 LMB04 4991000 LMB08 LMB07 LMB06 LMB05 C3-30A 4990900 LMB09 LMB10 LMB11 LMB12 4990800 LMB16 LMB15 LMB14 LMB13 LMB17 4990700 50 45 40 35 30 25 20 15 10 5 0 4990600 4990600 LMB18 697700 697800 697900 698000 698100 698200 LMB18 697700 697800 697900 698000 698100 698200 Figure *: PFC concentrations observed in sample sets 1 through 6 are contoured for comparison 20 50 45 40 35 30 25 20 15 10 5 0 LMB22 4992000 4991800 LMB21 4991600 LMB23 4991400 LMB19 4991200 LMB04 LMB01 LMB07 LMB06 4991000 LMB20 LMB10 LMB11 LMB24 LMB17 LMB16 4990800 697600 697800 698000 LMB13 698200 698400 Figure *: Reference map for passive atmospheric monitoring grid. 21 SORBE NT SET #1 928-08, 10-2208, BACKG ROUND SORBENT SET #2, During Tracer Injection 2-20-08 LMB-01 P-Atm 14 20 LMB-04 P-Atm 14 All Values in fl/L SORBENT SET #3, Immediately After Tracer Injection, 2-21-08 to 312-08 SORBENT SET #4, 3-12-08 to 4-08-08 SORBENT SET 5, 4/8/08 to 5/21/08 SORBENT SET 6, 5/21/08 to 9/17/08 Post injection averages 15 12 6 10 11 Site 545 13 12 7 9 10 LMB-06 P-Atm 6285 30 16 7 10 16 LMB-07 P-Atm 30 19 18 4 10 13 LMB-10 P-Atm 19 235 14 15 5 12 11 LMB-11 P-Atm 13 280 13 12 9 8 11 LMB-13 P-Atm 18 75 16 15 12 15 15 LMB-16 P-Atm 13 25 14 11 6 9 10 LMB-17 P-Atm 23 15 16 18 13 16 LMB-19 P-Atm 20 25 1 11 12 LMB-20 P-Atm 15 14 3 14 11 LMB-21 P-Atm 23 12 2 10 12 LMB-22 P-Atm 16 16 2 10 11 LMB-23 P-Atm 0 22 2 10 8 LMB-24 P-Atm 27 21 2 9 15 Average Standard deviation 16 3.78 753 1951.35 17 7.20 15 3.55 6 4.63 11 2.13 12 2.24 Median Max Min 14 23 13 53 6285 15 15 30 0 15 22 11 5 18 1 10 15 8 11 16 8 Table 2 Tracer in Passive Atmospheric Samples: Pre-, During-, and Post-Injection Results 22 Set 2 Passive Set 1 Passive LMB22 LMB22 4992000 4992000 4991800 28 4991600 LMB21 24 LMB23 6500 6000 5500 5000 4500 4000 3500 3000 2500 2000 1500 1000 500 0 4991800 LMB21 4991600 LMB23 20 16 4991400 4991400 12 LMB19 8 4991200 LMB04 LMB01 4 LMB07 LMB06 4991000 0 LMB20 LMB10 LMB11 LMB24 LMB19 4991200 LMB04 LMB01 LMB07 LMB06 4991000 LMB20 LMB10 LMB11 LMB24 LMB17 LMB13 LMB16 4990800 697600 697800 LMB17 698000 LMB13 LMB16 4990800 698200 698400 697600 697800 Set 3 Passive 698000 698400 Set 4 Passive LMB22 LMB22 4992000 4992000 4991800 28 LMB21 4991600 698200 4991800 LMB23 28 LMB21 24 4991600 16 4991400 20 16 4991400 12 LMB19 8 4991200 4991000 LMB07 LMB06 LMB20 12 LMB19 8 4991200 4 LMB04 LMB01 0 LMB07 LMB06 4991000 LMB20 LMB17 LMB13 LMB16 697600 0 LMB10 LMB11 LMB24 LMB17 4990800 4 LMB04 LMB01 LMB10 LMB11 LMB24 LMB13 LMB16 4990800 698000 698400 697600 697800 Set 5 Passive 698000 698200 698400 Set 6 Passive LMB22 LMB22 4992000 4992000 4991800 28 4991800 28 24 LMB21 4991600 24 LMB23 20 LMB23 20 LMB21 4991600 24 LMB23 20 16 16 4991400 4991400 12 12 LMB19 LMB19 8 4991200 0 LMB07 LMB06 4991000 8 4 LMB04 LMB01 4991200 4 LMB04 LMB01 LMB07 LMB06 4991000 LMB20 LMB20 LMB10 LMB11 LMB24 LMB17 LMB17 LMB16 4990800 697600 697800 698000 LMB16 4990800 LMB13 698200 0 LMB10 LMB11 LMB24 698400 697600 697800 698000 LMB13 698200 698400 Figure *: PFC concentrations observed in passive atmospheric monitoring sample sets 1 through 6 are contoured for comparison. 23 SORBE NT SET #1 928-08, 10-2208, BACKG ROUND SORBENT SET #2, During Tracer Injection 2-20-08 SORBENT SET #4, 3-12-08 to 4-08-08 SORBENT SET 5, 4/8/08 to 5/21/08 SORBENT SET 6, 5/21/08 to 9/17/08 Post injection averages LMB-01 P-Atm 14 20 15 12 6 10 11 LMB-04 P-Atm 14 545 13 12 7 9 10 LMB-06 P-Atm 6285 30 16 7 10 16 LMB-07 P-Atm 30 19 18 4 10 13 All Values in fl/L SORBENT SET #3, Immediately After Tracer Injection, 2-21-08 to 312-08 Site LMB-10 P-Atm 19 235 14 15 5 12 11 LMB-11 P-Atm 13 280 13 12 9 8 11 LMB-13 P-Atm 18 75 16 15 12 15 15 LMB-16 P-Atm 13 25 14 11 6 9 10 LMB-17 P-Atm 23 15 16 18 13 16 LMB-19 P-Atm 20 25 1 11 12 LMB-20 P-Atm 15 14 3 14 11 LMB-21 P-Atm 23 12 2 10 12 LMB-22 P-Atm 16 16 2 10 11 LMB-23 P-Atm 0 22 2 10 8 LMB-24 P-Atm 27 21 2 9 15 Average Standard deviation 16 3.78 753 1951.35 17 7.20 15 3.55 6 4.63 11 2.13 12 2.24 Median Max Min 14 23 13 53 6285 15 15 30 0 15 22 11 5 18 1 10 15 8 11 16 8 Table 3 Tracer in 3-Liter Active Atmospheric Samples: Pre- and Post-Injection Results 24