1. Produced Water from
Offshore Conventional Wells
John Veil
410-212-0950
john@veilenvironmental.com
www.veilenvironmental.com
Fossil Fuel Produced Water: Asset Or Waste?
Atlantic Council
Washington, DC
June 24-25 2013
2. 2
Topics for Discussion
Gulf of Mexico oil and gas statistics
Volume of offshore produced water
Unique features of offshore production
Characteristics of offshore produced water
Regulations for offshore discharge
Management of offshore produced water
3. Data for Gulf of Mexico Activity – from Bureau of Ocean Management
Well-by-Well Production data for oil, gas, and produced water can be seen at:
http://www.data.boem.gov/homepg/pubinfo/repcat/product/pdf/Production-A-2012.pdf
5. U.S. Produced Water Volume by Management Practice
for 2007 (1,000 bbl/year)
Injection for
Enhanced
Recovery
Injection
for
Disposal
Surface
Discharge
Total
Managed
Total
Generated
Onshore
Total 10,676,530 7,144,071 139,002 18,057,527 20,258,560
Offshore
Total 48,673 1,298 537,381 587,353 587,353
Total 10,725,203 7,145,369 676,383 18,644,880 20,995,174
5
Offshore – 91% goes to discharge
6. Unique Features of Offshore Production
Transportation to and from shore
Water depth
Cost
Environmental risk
– Salinity is not a big concern
Restrictions on footprint and weight
– Limits the types of treatment
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Platforms Sampled for Produced Water Study in 2005
Platforms sampled one time and selected at random
Platforms sampled three times and selected based on discharge volume and
type of hydrocarbon produced
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U.S. Regulatory System
Laws
• Clean Water Act
• Safe Drinking Water Act
Water Regulations
• National Pollutant Discharge Elimination System (NPDES)
program
• Effluent limitations guidelines (ELGs)
• Underground Injection Control (UIC) program
Permits and Guidance
• Environmental Protection Agency (EPA) regions and states issue
NPDES and UIC permits
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In the U.S., Most E&P Wastes Are Nonhazardous
Wastes
Resource Conservation and Recovery Act (1980) directed EPA
to review E&P wastes and either establish national regulations
or make a determination that existing state controls were
adequate
EPA issued determinations in 1988 and 1993
– E&P waste not subject to the hazardous waste requirements of RCRA
– States have regulatory authority over E&P wastes on state lands
• Can be more strict than federal requirements (I.e., can treat E&P
wastes as hazardous wastes at state discretion)
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NPDES Permits
Permits require
– Numerical limits
– Operational measures and controls
– Reporting and recordkeeping
– Self-monitoring
Numerical limits are based on the more stringent of
– Technology-based limits or best professional judgment
– Water quality-based limits (considers dilution and mixing)
Permits are issued for 5-year term and must be reissued
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Offshore and Coastal Effluent Limitations Guidelines (ELGs)
Minimum national discharge
standards for offshore
produced water:
– Oil and grease limits
• 29 mg/l monthly average
• 42 mg/l daily maximum
Discharge standards for coastal
produced water
– zero discharge except in Cook
Inlet, Alaska
– Offshore limits are required there
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General NPDES Permits
Cover group of similar dischargers in the same geographic
area
EPA regulations direct Regions to issue general permits for
offshore oil and gas activities
– EPA may issue individual permits in areas of biological concern
– Applicants may request individual permits
– Used by Regions 4, 6, 9, and 10 for coastal, territorial seas, and Outer
Continental Shelf areas
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EPA Region 4 – Eastern Gulf of Mexico
Region 4 -
Eastern Gulf of
Mexico OCS
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EPA Region 6 – Western Gulf of Mexico
Region 6 -
Western Gulf
of Mexico OCS
18. 18
EPA Region 6 – Western Gulf of Mexico
Region 6 -
Western Gulf
of Mexico -
Territorial Seas
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EPA Region 9 – California Coast
Region 9 –
California Coast
22. Basic Separation of Oil, Gas, and Water
Free-water knockout tank
separates three fluid phases plus
solids
Emulsions
- Heater-treater
- Demulsifying chemicals
Most common practice
• Onshore – pass through tank
battery, then inject
• Offshore – discharge
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Produced Water Management Options
Follow 3-tier water management/pollution prevention hierarchy
– Water minimization
– Recycle/reuse
– Treatment and disposal
Use most environmentally friendly option where possible
Tier 1 - Options for Minimizing Produced Water
Keep produced water from the entering the well
– Mechanical blocking devices
– Water shut off chemicals
Keep produced water from reaching the surface
– Downhole separation
– Sea floor separation
24. Waste Minimization – Keep Produced Water Out of the
Well
Mechanical blocking devices
– Packers
– Plugs
– Cement
Water shut-off chemicals
– Polymer gels
Source: Baker Hughes
Source: Baker Hughes
25. Waste Minimization – Manage Water without Bringing It to
the Surface
Downhole oil/water separation (DOWS)
– Tool that mounts in bottom of well and separates oil
from water
– Oil is pumped to the surface
– Water is pumped to injection zone without coming to
surface
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Waste Minimization – Manage Water without Bringing It to
the Surface
Separate at the sea floor
Source: ABB
Source: ABB
27. Tier 2 - Options for Recycle and Reuse of
Produced Water
• Injection for recovering more oil
• Injection for future use
• Injection for hydrological purposes
• Agricultural use
• Industrial use
• Drinking water and other domestic uses
• Secondary use
These are primarily applicable to onshore
production
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Tier 3 - Options for Treatment and Disposal of Produced Water
Practices to dispose of produced water
– Discharge
– Injection
– Evaporation
– Offsite commercial disposal
Of these, discharge is the predominant option for
offshore produced water
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Tier 3 - Options for Treatment and Disposal of Produced Water
Practices to dispose of produced water
– Discharge
– Injection
– Evaporation
– Offsite commercial disposal
Practices to remove salt and other inorganics from
produced water
– Membrane processes
– Ion exchange
– Capacitive deionization
– Thermal distillation
These are rarely used for treating offshore produced
water because salt is not a significant concern when
discharging into the ocean
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Tier 3 - Options for Treatment and Disposal of Produced Water
Practices to dispose of produced water
– Discharge
– Injection
– Evaporation
– Offsite commercial disposal
Practices to remove salt and other inorganics from produced water
– Membrane processes
– Ion exchange
– Capacitive deionization
– Thermal distillation
Practices to remove oil and grease and other organics from
produced water
– Physical separation
– Flotation
– Coalescence
– Combined physical and extraction
– Solvent extraction
– Adsorption
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Produced Water Offshore Treatment Technology
There are many types of produced water treatment used at
offshore facilities
– Primarily designed to reduce free oil and other dissolved organics in order
to meet the oil and grease limit of 29 mg/l average and 42 mg/l maximum
Oil and grease is a variable parameter
– Free oil (large droplets, easy to remove)
– Dispersed oil (small droplets)
– Dissolved oil (difficult to remove)
Measurement of oil and grease depends on analytical method
39. Conclusions and Final Thoughts
There is a lot of produced water generated
each year from several thousand offshore oil
and gas wells
Nearly all produced water from offshore wells
is treated on the platform and discharged to
the ocean under the authority of a permit
A variety of treatment technologies are
available to clean produced water before
discharge