the origin of methane and its effect on the aquifer. · Maye ‐HW 14 Mn x 10,000 EhPostdrill in mV...
Transcript of the origin of methane and its effect on the aquifer. · Maye ‐HW 14 Mn x 10,000 EhPostdrill in mV...
Determining the origin of methane and its effect on the aquifer.
Agenda Geologic history Methane characteristics The ratio of carbon isotopes in methane. The unique ratio of hydrocarbons in the Marcellus F iFormation
Identifying the age of the methane. Th ff t th d d illi h th if The effects methane and drilling have on the aquifer and trend over time.
Conclusions Conclusions.
EnvironmentEnvironment of DepositionMiddle Devonian (385 MA)
Osborn S G et al. PNAS 2011;108:8172‐8176
h h l h d b d dMethane is the principal hydrocarbon detected in all stray natural gas migration incidents
Exposure limit (gas phase): TLV‐TWA: 1,000 ppm (ACGIH, 10/2009) Methane (CH4) is the simplest paraffin hydrocarbon gas Methane is generated by microbial & thermogenic processes Flammable, colorless, odorless. Specific gra it 0 (NTP) air Specific gravity: 0.555 (NTP) air = 1 Explosive range: 5‐15% in ambient air Solubility in water: 26‐32 mg/l (1 atm.)y 3 g/ ( ) Non toxic, no ingestion hazard Simple asphyxiant, explosion hazardMethane can migrate as free gas or dissolved in the groundwater
Isotopic Balance Researchers have determined that there are common carbon & hydrogen isotopic compositions or signatures for thermogenic gas associated with coal & natural gas, drift gas,
So by collecting numerous gas samples of known origin a database has been
d l d d fi i ti f g g g g
and other near surface microbial gases . Natural carbon is nearly all isotope 12, with 1.11 percent being isotope 13
developed and fingerprinting of gas samples may performed.
isotope 13. Organic material contains less C‐13, because bacteria /photosynthesis preferentially selects C‐12 over C‐13. p y p y 3
Oil and natural gas typically show a C‐12 to C‐13 ratio similar to that of the biological materials from which they are to have originated originated.
Sh l GShale Gas Increasing formation Increasing formation
temperature leads to diagnostic methane/ethane and isotopic ratiosThe normal sequence of carbon isotopic compositions is:ratios
Tight gas shales such as the Marcellus often have uniquely diagnostic isotopic reversals
δ13C methane (C1) < δ13C ethane (C2) < δ13C propane (C3) and < δ13C butane (C4)
δ13C1 < δ13C2 < δ13C3 and < δ13C4diagnostic isotopic reversals (e.g. δ13C‐CH4 heavier than δ13C‐C2H6)
In the Marcellus they are fully reversed ‐ δ13C1 > δ13C2 > δ13C3
Also hydrogen isotopic compositions (δ2H) of C1 and C2 are also reversed. Uniquely identifiable when
paired with additional proxies (e.g. noble gases)
I t G h i tIsotope GeochemistryEasily Distinguishes:
Molecular: Methane/Ethane
Isotopic: Carbon and
Biogenic vs. Thermogenic(e.g. Schoell, 1983; Coleman et al, 1991; Baldassare and Laughrey, 1998)
Hydrogen isotopes (δ13C‐CH4, δ2H‐CH4, δ13C‐C2H6)
N bl G
Distinguishing different thermogenic gases (e.g. Schoell et al, 1983; Jenden et al, 1993;
Noble Gases Revesz et al, 2010; Tilley et al, 2010)
?What’s best for distinguishing thermally mature gases?y g
13 C fractionation
2 H fractionation
% argon
2 H fractionation
% argon
‐29 ‐160
% nitrogen
HW04
HW02zHW05
HW12
HW17HW24
HW02
HW14
HW06
HW08a
HW12
HW01
Sample Quality ‐ degassing?Sample Quality degassing?
ideal
Three Patterns of Contamination1. Short term (< 1 year) disruption to the aquifer
caused by drilling. ( ) di i i i 2. Long term (> 3‐4 year) disruption or contamination
of the aquifer caused by drilling/fracking, releases or other situationsother situations.
3. Natural Background Conditions with high levels of metals and anions.
Type 1: Short Term Disruption
HW04Gas Well Activity HW04
1000
1200
25000
30000
35000
Baker Wells ‐ 1,300 ft to SSESpud ‐ Baker 1 11 Aug. 2008
‐ Baker 2 11 Dec. 2009 Methane isotope sample probably plots outside Marcellus Shale age zone. (interestingly the gas appears older, maybe deeper than Marcellus Shale)
400
600
800
5000
10000
15000
20000
0
200
4
‐10000
‐5000
0
5
10‐Aug‐08 26‐Feb‐09 14‐Sep‐09 2‐Apr‐10 19‐Oct‐10 7‐May‐11 23‐Nov‐11g 9 4 p 9 p 9 y 3
Methane_ug_l Eh in Mv
Linear (Methane_ug_l) Linear (Eh in Mv)Normal range of Eh in groundwateris 200 to ‐100 Mv. Freshwaterstreams 300 to 500 Mv.
9 pH
6
7
8
9 p
4
5
12‐May‐08 28‐Nov‐08 16‐Jun‐09 2‐Jan‐10 21‐Jul‐10 6‐Feb‐11 25‐Aug‐11
Analysis_Ph_ph_Units
80018000 HW‐7
600
700
12000
14000
16000
l
Gas Well ActivityBaker Wells ‐ 1,300 ft to SSESpud ‐ Baker 1 11 Aug. 2008
‐ Baker 2 11 Dec. 2009
400
500
8000
10000
12000
Metha
ne in ug
/l
100
200
300
2000
4000
6000
00
2000
9‐Sep‐08 28‐Mar‐09 14‐Oct‐09 2‐May‐10 18‐Nov‐10 6‐Jun‐11 23‐Dec‐11
M h l Eh M M /l Li (M h l) Li (Eh M ) Li (M /l)Methane_ug_l Eh Mv Manganese ug/l Linear (Methane_ug_l) Linear (Eh Mv) Linear (Manganese ug/l)
8
8.5
pH
7
7.5
12/18/2008 3/28/2009 7/6/2009 10/14/2009 1/22/2010 5/2/2010 8/10/2010 11/18/2010 2/26/2011 6/6/2011 9/14/2011 12/23/2011
45014000 HW17
350
400
45
12000
4
250
300
8000
10000
g/l & M
nin ug/l
Methane isotope sampling indicate Marcellus Shale age
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150
200
4000
6000
Metha
ne in m
g
Eh in M
vMarcellus Shale age gas at this data point
.
0
50
100
0
2000
M
Eh Mv Mn ug/l Methane ug/l Eh Trend Methane Trend
G ll S d i Note incomplete data set Gas Well Date Spud Distance to HW17Lewis 5/28/2008 670 ft.Ely 4H & 6H 3/27/2008 1,360 ft.Costello 1 7/16/2008 1,350 ft.
50045
HW1 ‐Hubert
300
400
30
35
40Methane isotope sampling indicate Marcellus Shale age gas at this data point
g/l
200
300
20
25
30
Eh in M
v
Gesford 3 spud July 28, 2008
Metha
ne in m
g
0
100
5
10
15M
‐100016‐Dec‐08 16‐Apr‐09 16‐Aug‐09 16‐Dec‐09 16‐Apr‐10 16‐Aug‐10 16‐Dec‐10 16‐Apr‐11 16‐Aug‐11 16‐Dec‐11
Methane mg/l Eh in Mv Methane Trend Eh Trend
HW1 lacked data for nearly all constituents, particularly for the years 2009‐2010
Type 2: Long Term Disruption
45030 Gesford 2
HW8
Methane isotope sampleMethane and Manganese
300
350
400
20
25
Remediation of well on April 1, 2009
Methane isotope sampleplots outside MarcellusShale age zone.
Gesford 2 Spud Sept. 23, 2008Stimu Nov‐ Dec 2008
100
150
200
250
10
15
0
50
0
5
29‐Oct‐08 17‐May‐09 3‐Dec‐09 21‐Jun‐10 7‐Jan‐11 26‐Jul‐11 11‐Feb‐12
Methane in mg/l Mn in ug/l Linear (Methane in mg/l) Linear (Mn in ug/l)Methane in mg/l Mn in ug/l Linear (Methane in mg/l) Linear (Mn in ug/l)
789
605
705pH ‐ Eh
234567
205
305
405
505
01
5
105
29‐Oct‐08 17‐May‐09 3‐Dec‐09 21‐Jun‐10 7‐Jan‐11 26‐Jul‐11 11‐Feb‐12
Eh in Mv Analysis_Ph_ph_Units Linear (Eh in Mv) Linear (Analysis_Ph_ph_Units)
Gas is Gas0
500
Interbeddedsandstone,siltstoneGas is Gas
Thermogenic gas is present throughout the upper Devonian
1,000
Catskill
& shale
g ppformations. Drilling creates pathways, either temporary or permanent, that allows gas to migrate to the shallow aquifer
1,500
2,000
Sandstone
surface
migrate to the shallow aquifer near surface.
Shallower (non Marcellus) gas may also include higher amounts
2,500Gas shows
h beneath s
may also include higher amounts of H2S which can have a greater impact on groundwater.
In some cases these gases
3,000
3,500
interbeddedsiltstone and
shale
Depth
In some cases, these gases disrupts groundwater quality
4,000
From Gesford 2 Well Record and Completion Report
4,500
5,000Tully Limestone
Gas show
600
700
18.00
20.00
Maye ‐HW 14 Mn x 10,000
Eh in mV
Mn_mg_l
Methane ‐mg/l
‐Postdrill‐Mn 62 ug/l
TSS 35.5 mg/l TDS 127 mg/l
Methane isotope sampling indicate Marcellus Shale age
600
700
18,000.00
20,000.00
‐HW 14
‐Postdrill‐Mn 62 ug/l
TSS 35.5 mg/l TDS 127 mg/lFe 3 38 mg/l
Methane isotope sampling indicate
500
600
14.00
16.00
gFe 3.38 mg/lCl‐ 12.7 mg/l
Major rain event10" 7 9 Sept 2011
gas at this data point .
500
600
14,000.00
16,000.00Mnx 10,000
Fe 3.38 mg/lCl‐ 12.7 mg/l Marcellus Shale age
gas at this data point .
G W ll A i i
40012.00
Predrill
10 7‐9 Sept 2011
40012,000.00 Eh trend
h d
Gas Well ActivityBaker Wells 1,100 ft. eastSpud ‐ Baker 1 11 Aug. 2008
‐ Baker 2 11 Dec. 2009
3008.00
10.00 ‐Predrill‐Mn ‐ na
TSS <5 mg/lTDS 149mg/lFe 0.03mg/lCl‐ 7.9mg/l
3008,000.00
10,000.00 methane trend
200
4.00
6.00200
4,000.00
6,000.00
‐Predrill‐Mn ‐ na
TSS <5 mg/l
0
100
0.00
2.00100
2,000.00
TSS <5 mg/lTDS 149mg/lFe 0.03mg/lCl‐ 7.9mg/l
00.00
12040
HW‐2
80
100
120
30
35
40
l Mn
Methane isotope sampling indicate
Marcellus Shale age
40
60
15
20
25
Metha
ne m
g/
Mnug/l
Stimulation30 Sept. 09
Completion 12 Sept. 2008
ggas at this data point
.
1.80
12.50
3.200
20
0
5
10
Arsenic ug_l
Manganese_ug_l
Methane mg l
Costello 1V 2VSpud Date: 7/26/08 8/19/08C D / / 8 / / 8 l d Methane_mg_lComp Date 9/12/08 11/11/08Stim Date 9/30 /09 1/10/09
Note incomplete data set
70300HW6
Gesford 3 & 9 remediation
Methane isotope sampling indicate Marcellus Shale age gas at this data point
50
60
150
200
250
v
May 23 & 24, 2010 age gas at this data point
10x ug/
l
30
40
50
100
150
Eh in M
v
Gesford 3 spud July 28, 2008 m
g/l As
10
20
‐50
0
y
Met
han
e
0‐100
Eh in Mv Methane mg/l Arsenic ug/lEh in Mv Methane mg/l Arsenic ug/l
7
9
11
5
7
9‐Jul‐08 9‐Jan‐09 9‐Jul‐09 9‐Jan‐10 9‐Jul‐10 9‐Jan‐11 9‐Jul‐11 9‐Jan‐12
pH
70300HW6
50
60
150
200
250
Mv
As 10
x
30
40
50
100
150
Eh in M
ane mg/
l Graph Cautions:
Data was selected on basis of the most representative of well conditions . Due to incomplete data description, in some cases data may not be representative of the well or the data was not plotted. Due to this
10
20
‐50
0
Met
hug/
luncertainty, trend may differ with different data use.
0‐1009‐Jul‐08 9‐Jan‐09 9‐Jul‐09 9‐Jan‐10 9‐Jul‐10 9‐Jan‐11 9‐Jul‐11 9‐Jan‐12
Eh in Mv Methane mg/l Arsenic ug/l Linear (Eh in Mv) Power (Methane mg/l)
7
9
11
5
7
9‐Jul‐08 9‐Jan‐09 9‐Jul‐09 9‐Jan‐10 9‐Jul‐10 9‐Jan‐11 9‐Jul‐11 9‐Jan‐12
pH
Type 3: Naturally Occurring Contamination
350
400
16000
18000HW47 ‐
No isotope
250
300
12000
14000
Mv&
in ug/l
l
No isotope sample collected
150
200
8000
10000
Eh in M
Arsen
ic
Metha
ne in m
g/l
Post 1No 20 0
100
150
4000
6000
Arsenic ug/l
M Nov. 11, 2010
0
50
0
2000Arsenic ug/l
Methane ug/l
Eh in Mv
When no data is plotted, no data was available.
Conclusions Methane is released during the drilling and perhaps during the fracking
process and other gas well work.
Methane is at significantly higher concentrations in the aquifers after gas Methane is at significantly higher concentrations in the aquifers after gas drilling and perhaps as a result of fracking and other gas well work.
The methane migrating into the aquifer is both from the shallower ( ) f ti d ld M ll Sh l ( d h (younger age) formations and older Marcellus Shale (and perhaps even older formations).
Methane and other gases released during drilling (including air from the drilling) apparently cause significant damage to the water quality.
In some cases the aquifers recover (under a year) but, in others cases the damage is long term (greater than 3 years).damage is long term (greater than 3 years).