water in the oil and gas cycle, including hydraulic fracturing · water in the oil and gas cycle,...

Water in the Oil and Gas Cycle, including Hydraulic Fracturing

Mark Engle and *Bridget R. Scanlon

U.S. Geological Survey

*Bureau of Economic Geology, Jackson School of Geosciences,

Univ. of Texas at Austin, Texas1

CUAHSI's Spring 2016 Cyberseminar SeriesWater Energy Nexus

https://www.cuahsi.org/cyberseminars2

Outline

• Background (conventional and unconventional reservoirs)

• Water use for oil and gas production from conventional reservoirs

• Water use for hydraulic fracturing – Trends and controls

– Water intensity per unit of energy

• Water demand for hydraulic fracturing relative to water supplies

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Unconventional vs. Conventional Hydrocarbon Reservoirs

Modified from Schenk and Pollastro, 2002

Unconventional resources (continuous resources): oil and natural gas in the source rock.Conventional resources: oil and natural gas that have migrated from source rock into astructural or stratigraphic trap with distinct oil water interface.

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5

Marcellus

Fayetteville

Haynesville

Barnett

Bakken

Eagle Ford

Permian

Basin

Woodford

Niobrara

Shale Oil and Gas Plays in the U.S.

Base map: National Geographic6

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2000 2002 2004 2006 2008 2010 2012 2014 2016

US

tigh

t o

il p

rod

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(1

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ay)

Eagle Ford

Bakken

Rest US

Niobrara

Permian

U.S. Shale Oil Production

Shale and tight oil production accounted for ~ 50% of U.S. crude oil production in 2014.

Energy Information Administration7

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dry

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Marcellus

HaynesvilleEagle Ford

Barnett

Fayetteville

UticaRest of US Shale

U.S. Shale Gas Production

Shale gas production accounted for ~ 50% of U.S. natural gas production in 2014.

Energy Information Administration8

Outline

• Background (conventional and unconventional reservoirs)

• Water use for oil and gas production from conventional reservoirs

• Water use for hydraulic fracturing – Trends and controls

– Water intensity per unit of energy

• Water demand for hydraulic fracturing relative to water supplies

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Water Use for Oil and Gas Production from Conventional vs Unconventional Reservoirs

• Conventional Reservoirs: – Water use: well drilling

– Secondary recovery (water flooding) or tertiary recovery (steam or CO2 injection)

– There is no secondary or tertiary recovery for gas production

• Unconventional Reservoirs: – Horizontal drilling and hydraulic fracturing

– Water and proppant injected to produce oil and gas

– We are recovering 5 – 10% of the resource in place; future enhanced recovery techniques may require more water

10Lampert et al., 2015Scanlon et al., 2015

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1930 1940 1950 1960 1970 1980 1990 2000

Vo

lum

e (

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6b

bl/

d)

Example of Water Use and Oil Production in a Conventional Reservoir

Primary production until mid 1960s, water flooding ->secondary production of oilDenver Unit of the Wasson Field, Permian Basin, Texas

Water flooding

Oil production

Modified National Energy Technology Lab, 2010; Healy et al., 2015

Primary Secondary

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1930 1940 1950 1960 1970 1980 1990 2000

Vo

lum

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Increased volumes of produced water lags water flooding. Water for flooding in the PermianChanged from 75% freshwater in 1995 to 20% freshwater in 2010.

Water flooding

Oil production

Waterproduction

Modified National Energy Technology Lab, 2010; Healy et al., 2015; Scanlon et al., ES&T, 2014 ES&T

Example of Water Use and Oil Production in a Conventional Reservoir

Primary Secondary

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CO

2in

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(1

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ft3)

Vo

lum

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bb

l/d

)

Oil production

Water flooding

Waterprod.

CO2

injection

Example of Water Use and Oil Production in a Conventional Reservoir

Primary Secondary Tertiary

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Comparison of Conventional and Unconventional Oil Production in the Bakken

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1950 1960 1970 1980 1990 2000 2010

Cu

mu

lati

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ells

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(1

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0s)

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mu

lati

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. (1

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rod

. (1

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bb

l)

Conventional Unconventional

Similar oil production 60 yr from conventional reservoir vs 10 yrfrom unconventional reservoir

Similar number of wells drilled in both conventional and unconventional reservoirs14

Scanlon et al., ES&T, in rev.

Outline

• Background (conventional and unconventional reservoirs)

• Water use for oil and gas production from conventional reservoirs

• Water use for hydraulic fracturing – Trends and controls

– Water intensity per unit of energy

• Water demand for hydraulic fracturing relative to water supplies

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Data Sources

National DatabaseWater useWell completionOil, gas, & water production

State Databases: oil, gas & water production

National DatabaseWater use for Hydraulic fracturingChemicals used in HF

Water use for HFWell completionOil, gas, & water productionDisposal of produced water

State Database: water use for HFWater sourcesPermitting and regulations

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Marcellus

Fayetteville

Haynesville

Barnett

Bakken

Eagle Ford

Permian

Basin

Woodford

Niobrara

~4.4

5.3

5.1

3 - 5

4 - 5

~1

~2

~0.4

Water Use for Hydraulic Fracturing (106 gal/well)

Freyman et al., 2013; Nicot et al., 2014; Scanlon et al., 2014; Kondash & Vengosh, 2015

~2

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Controls on Water Use for Hydraulic Fracturing

• Vertical vs horizontal wells

• Length of laterals

• Geology

• Number of frac stages

• Frac fluid types (slickwater, gels, hybrids)

• Operator

• Economics

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Trends in Water use in the Bakken Play

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Mea

n H

F (1

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gal/

wel

l)

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Mea

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ft)

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Mea

n H

F (g

al/f

t)

Water use/well ↑ 10 x

Lateral length ↑ 2 x

Water use/ft of lateral ↑ 8 x

Scanlon et al., ES&T. in rev.19

2014 water use for HF: mean 3.7 mgal/wellmedian 3.0 mgal/well5th percentile 1.6 mgal/well95th percentile 9.2 mgal/well

Water Use per Unit of Energy in the Eagle Ford Shale Play

Zone HF Oil HF/Oil EUR HF/EURmgal/well mgal/well H2O/Oil mgal/well H2O/Oil

Oil 4.6 3.0 1.52 13 0.34

Scanlon et al., ES&T. 2014

HF: hydraulic fracturingEUR: Estimate ultimate recovery of oilmgal: million gallonsWater use for hydraulic fracturing of oil wells similar to gas wells in Eagle Ford

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How does water use for shale oil production compare with conventional oil production?

Scanlon et al., ES&T. 2014; Wu et al., 2011

Water use for hydraulic fracturing to produce oil is in lower range of water use for conventional production.We are using more water for HF because we are producing more oil.

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Outline

• Background (conventional and unconventional reservoirs)

• Water use for oil and gas production from conventional reservoirs

• Water use for hydraulic fracturing – Trends and controls

– Water intensity per unit of energy

• Water demand for hydraulic fracturing relative to water supplies

22

Water Scarcity Concerns for Hydraulic Fracturing

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Schematic of Eagle Ford Shale Play

Scanlon et al., Env. Res. Lett. 201424

Water Sources:FreshwaterProduced waterBrackish GW

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1930 1950 1970 1990 2010D

epth

to

wat

er (

ft)

Carrizo-Wilcox Aquifer

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1970 1980 1990 2000 2010D

epth

to

wat

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ft)

Jasper Aquifer

IMPACTS

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1960 1970 1980 1990 2000 2010

Dep

th t

o w

ater

(ft

)

Carrizo-Wilcox Aquifer

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Med

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FP/

HF

(%)

Production month

Potential for Reuse/Recycling of Flowback-Produced WaterEagle Ford Shale Play

Flowback-produced water volumes represent only 5 – 6% of the water required for hydraulic fracturing in the first couple of months. Marcellus: 90% of produced water recycled represents 10 – 30% of waterused for hydraulic fracturing 26

Scanlon et al., ERL, 2014

Alternatives to Freshwater in the Eagle Ford:Brackish Groundwater

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Brackish groundwater

Freshgroundwater

20-yr HF water demand

WATER SUPPLY relative to 20-yr HF Water DEMAND (BGAL)

80 K10 K

0.3 K

Scanlon et al., Env. Res. Lett. 2014

330 bgal ~ 1.0 million acre feet ~ 1.3 km3

~ 10% of past GW depletion from irrigation

62,000 additional wells

Summary

• Water use for hydraulic fracturing is higher than that for conventional gas production but is in the low range of that for conventional oil production.

• Water use for hydraulic fracturing varies among plays as a result of varying number of vertical vs horizontal wells, length of laterals, number of fracstages, and frac fluid types.

• Water scarcity concerns need in depth evaluation of water demand relative to supplies at the local scale.

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Bridget.Scanlon@beg.utexas.edu

Sponsors:

Contact: Bridget R. Scanlon

SUTUR

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Reference Material

• Freyman, M. (2014), Hydraulic Fracturing & Water Stress: Water Demand by the Numbers: Shareholder, Lender & Operator Guide to Water Sourcing, CERES Report, www.ceres.org.

• Gallegos, T. J., B. A. Varela, S. S. Haines, and M. A. Engle (2015), Hydraulic fracturing water use variability in the United States andpotential environmental implications, Water Resources Research, 51(7), 5839-5845.

• Healy, R. W., W. A. Alley, M. A. Engle, P. B. McMahon, and J. D. Bales (2015), The Water-Energy Nexus - An Earth Science Perspective, U.S. Geol. Surv. Circular 1407, 107 p. .

• Lampert, D. (2015), Comment on “Comparison of Water Use for Hydraulic Fracturing for Unconventional Oil and Gas versus Conventional Oil,” Environmental Science & Technology, 48:12386-12393, September 18, 2014.

• Nicot, J. P., B. R. Scanlon, R. C. Reedy, and R. A. Costley (2014), Source and fate of hydraulic fracturing water in the Barnett Shale: A historical perspective, Environmental Science & Technology, 48(4), 2464-2471.

• Nicot, J. P., and B. R. Scanlon (2012), Water Use for Shale-Gas Production in Texas, US, Envir. Sci. & Technol. , 46(6), 3580-3586.

• Kondash, A., and A. Vengosh (2015), Water footprint of hydraulic fracturing, Environmental Science & Technology Letters, 2(10), 276-280.

• Scanlon, B. R., R. C. Reedy, and J. P. Nicot (2014), Will water scarcity in semiarid regions limit hydraulic fracturing of shale plays?, Environmental Research Letters, 9, DOI 10.1088/1748-9326/9/12/124011, 9(12). http://iopscience.iop.org/1748-9326/9/12/124011

• Scanlon, B. R., R. C. Reedy, and J. P. Nicot (2014), Comparison of water use for hydraulic fracturing for unconventional oil and gas versus conventional oil, Environmental Science & Technology, 48(20), 12386-12393.

• Scanlon, B. R., I. Duncan, and R. C. Reedy (2013), Drought and the water energy nexus in Texas, Environ. Res. Lett., 8(4), 045033, doi:10.1088/1748-9326/8/4/045033. http://iopscience.iop.org/1748-9326/8/4/045033

• Scanlon, B. R., R. C. Reedy, I. Duncan, W. F. Mullican, III, and M. Y. Young (2013), Controls on Water Use for Thermoelectric Generation: Case Study Texas, U.S., Env. Sci. & Tech., 47, 11326-11334, 47.

• Scanlon, B. R., R. C. Reedy, and J. P. Nicot (2015), Response to Comment on "Comparions of Water Use for Hydraulic Fracturing for Unconventional OIl and Gas versus Conventional Oil", Envir. Science & Technol., 10.1021/acs.est.5b01497.

• Wu, M., and Y. Chiu (2011), Consumptive Water Use in the Production of Ethanol and Petroleum Gasoline — 2011 Update, Argonne National Laboratory Technical Report ANL/ESD/09-Update 2011, 84 p. .

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Produced Waters and their Management

• Produced water volumes from conventional and continuous hydrocarbon plays

• Chemistry and quality of produced waters

• Disposal, re-use, and recycling options

1Photo: Tanya GallegosPhoto: Tanya Gallegos

Produced Water Definition• Definition: Any water produced from a hydrocarbon

well, including flowback water, formation water, injected fluids, water condensing from the gas phase, and mixtures thereof (also referred to as co-produced water). Source: USGS Fact Sheet 2014-3104

2

Origin of produced water-Marcellus Shale

• δ18O shift in produced water over time

• Oxygen-isotope exchange reactions not that fast

• Mixing between injected water and formation fluid

Rowan et al., 20153

National Scale Produced Water Volumes – 2007 vs. 2012

2007 Data 2012 Data

Reference Clark and Veil, 2009 Veil, 2015

Total US Prod. Water Volume

21 billion BBL 21.2 billion BBL

Total US Oil Production 1.75 billion BBL 2.26 billion BBL

Total US Gas Production 24.4 TCF 29.7 TCF

Nat’l water-oil ratio 7.6 BBL/BBL 9.2 BBL/BBL

Nat’l water-gas ratio 260 BBL/MMCF 97 BBL/MMCF

• Oil production increased 29%

• Gas Production increased 22%

• Produced water volume did not increase

1 BBL = 42 gallons1 MMCF = 106 ft3

4

Produced Water Volumes by State (2012 Data)

• Top 5 states generate >75% of produced waters

• No basin-level data available

• Voluntary data only– Texas and

Oklahoma provide no public data

Data source: Veil, 20155

Basin-level trends: Natural gas production in Pennsylvania

• From 2008 to 2013

– Natural gas withdrawals increased ~1600%

– By Dec. 2013, 94% of that from shale gas

– Produced water increased ~900%

Data Source: Energy Information Administration (eia.gov) 6

Water-Oil Ratios in the Eagle Ford Shale

• National WOR = 9.2 BBL/BBL– Veil, 2015

• Eagle Ford Shale (n=47)– Median = 0.42

BBL/BBL

Modified from Dubiel et al., 2012

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Decline Curves – A source of complexity to water management

Healy et al., 20158

Geochemistry of produced waters

• Salts– Up to and exceeding 400

g/L

• Trace elements– Everything

• Organics– Rather variable

• 100-5,000 mg/L

• Naturally-occurring radioactive material– 228Ra (Th-decay chain)– 226Ra (U-decay chain)

• Oil and grease

– Try to minimize

• Suspended sediment

– Can include proppant

• Bacteria and microbes

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Total Dissolved Solids Map

BulkSeawater(35 g/L)

Source: USGS Produced Waters Geochemical Database, Version 2.2

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Trends in major ion composition with salinity

Anions: Cl is the only major anion at TDS > 50 g/L• SO4 loss due to sulfate reduction

and gypsum ppt.• HCO3

- loss due to carbonate ppt.

Cations: Ca/Na ratio increased with salinity• Halite saturation, ion exchange and

albitization play a roleK and Sr abundance increase with salinity

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Elemental Abundance in Produced Waters

Source: USGS Produced Waters Geochemical Database, Version 2.2 12

Changes in solute concentrations over time

• Most solutes increase over the first few weeks

– Mixing with formation brine +/- water-rock interaction

• DOC, SO4, and a few others may decrease

Time series from 3 Marcellus Shale wells

Rowan et al., 2015

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Organic compounds

• Natural Compounds

– Alkanes, PAHs, heterocyclic compounds

• Injected Compounds

– Friction reducers, biocides, scale inhibitors, etc.

– Decreases with production

Time (min)

Extractable Hydrocarbon GC/MS

Total Ion Current Chromatograms

Marcellus Shale Well

2,2,4-trimethyl-1,3-Pentanediol

Resp

on

se I

nte

nsit

y (

Rela

tive U

nit

s)

Source: Orem et al., 2014

Day 1

Day 243

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Carboxylic acid anions

• Anions of carboxylic acids can be in very high concentration

– 80-120 °C max

• Primarily acetate

– At <80 C, propionate is dominant

Kharaka et al., 1988

Sum of C2-C5 carboxylic acid anions

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Disposal methods for U.S. onshore produced waters (2012 Data)

• >85% of water is injected

• Surface discharge acceptable for some CBM plays

• Beneficial reuse still <1%

Data source: Veil, 201516

Regional variations by type - California

Jan 2011-June 2014 DataEsser et al., 2015

Predominantly hydraulically fractured pools

Predominantly nothydraulically fractured pools

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Regional variations with time and laws – Pennsylvania, 2008-2011

• PA has very few class II UIC wells

• Changes in regs– 2010: PA

limited effluent to <250 mg/L; 27 grandfathered sites

– May 2011: All POTWs asked to stop accepted shale gas waste water

Wilson and VanBrieson, 201218

Recycling of produced water for hydraulic fracturing

Frac fluid formulations increasingly

tolerant

Can’t recycle when you’re not

drilling

Chen and Carter, 201619

Produced Water Summary

• Despite increased hydrocarbon production, produced water volumes are not increasing

• Salinity increases with time

• Organics tend to decrease with time– Anions of carboxylic acids can be high

• Most produced waters are dominated by Na, Ca, and Cl

• Most water is disposed of by injection

• Disposal methods vary by region and with time

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Questions?

Contact info:Mark EngleEastern Energy Resources Science CenterU.S. Geological SurveyLocated in Dept. of Geological SciencesUniversity at Texas at El Pasoengle@usgs.gov

Useful Links

• USGS Produced Waters Geochemical Database, Map Viewer

– http://eerscmap.usgs.gov/pwapp/

• USGS Produced Waters Webpage:

– http://energy.usgs.gov/EnvironmentalAspects/EnvironmentalAspectsofEnergyProductionandUse/ProducedWaters.aspx

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References CitedClark, C. E., & Veil, J. A. (2009). Produced water volumes and management practices in the United States. Argonne National Laboratory Report ANL/EVS/R-09/1, 60 p.

Chen, H., & Carter, K. E. (2016). Water usage for natural gas production through hydraulic fracturing in the United States from 2008 to 2014. Journal of Environmental Management, 170, 152–159. http://doi.org/10.1016/j.jenvman.2016.01.023

Dubiel, R. F., Pitman, J. K., Pearson, O. N., & Pearson, K. (2012). Assessment of undiscovered oil and gas resources in conventional and continuous petroleum systems in the Upper Cretaceous Eagle Ford Group, U.S. Gulf Coast Region, 2011. U.S. Geological Survey Fact Sheet 2012-3003, 2 p.

Engle, M. A., Cozzarelli, I. M., & Smith, B. D. (2014). USGS investigations of water produced during hydrocarbon reservoir development. U.S. Geological Survey Fact Sheet 2014-3104, 4 p.

Esser, B. K., Beller, H. R., Carroll, S. A., Cherry, J. A., Gillespie, J., Jackson, R. B., Jordan, P. D., Madrid, V., Morris, J. P., Parker, B. L., Stringfellow, W. T., Varadharajan, C., & Vengosh, A. (2015). Recommendations on model criteria for groundwater sampling, testing, and monitoring of oil and gas development in California (Draft Report). Lawrence Livermore National Laboratory Report LLNL‐TR‐669645, 286 p.

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References CitedHealy, R. W., Alley, W. M., Engle, M. A., McMahon, P. B., & Bales, A. J. D. (2015). The Water-Energy Nexus—An Earth Science Perspective. U. S. Geological Survey Circular 1407, 108 p.

Kharaka, Y. K., Gunter, W. D., Aggarwal, P. K., Perkins, E. H., & Debraal, J. D. (1988). SOLMINEQ.88: A computer program for geochemical reaction modeling of water-rock interaction. U.S. Geological Survey Water-Resources Investigations Report 88-4227, 420 p.

Orem, W., Tatu, C., Varonka, M., Lerch, H., Bates, A., Engle, M., Crosby, L., & McIntosh, J. (2014). Organic substances in produced and formation water from unconventional natural gas extraction in coal and shale. International Journal of Coal Geology, 126(0), 20–31.

Rowan, E. L., Engle, M. A., Kraemer, T. F., Schroeder, K. T., Hammack, R. W., & Doughten, M. W. (2015). Geochemical and isotopic evolution of water produced from Middle Devonian Marcellus shale gas wells, Appalachian basin, Pennsylvania. AAPG Bulletin, 99(02), 181–206.

Wilson, J. M., & VanBriesen, J. M. (2012). Oil and gas produced water management and surface drinking water sources in Pennsylvania. Environmental Practice, 14(04), 288–300.

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