Produced Water from Offshore Conventional

WellsJohn Veil410-212-0950

john@veilenvironmental.comwww.veilenvironmental.com

Fossil Fuel Produced Water: Asset Or Waste?Atlantic Council Washington, DCJune 24-25 2013

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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

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

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Produced Water Volume Profile for Conventional Well

U.S. Produced Water Volume by Management Practice for 2007 (1,000 bbl/year)

Injection for Enhanced Recovery

Injection for

DisposalSurface

DischargeTotal

ManagedTotal

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

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Offshore – 91% goes to discharge

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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Summary of Offshore Produced Water Analysis

Parameter Mean Median Maximum Minimum

BOD, mg/L 957 583 11,108 80

Dissolved BOD, mg/L 498 432 1,128 132

Suspended BOD, mg/L 76 57 146 16

TOC, mg/L 564 261 4,880 26

Dissolved TOC, mg/L 216 147 620 67

Suspended TOC, mg/L 32 13 127 5

Nitrate, mg/L 2.15 1.15 15.80 0.60

Nitrite, mg/L 0.05 0.05 0.06 0.05

Ammonia, mg/L 74 74 246 14

TKN, mg/L 83 81 216 17

Orthophosphate, mg/L 0.43 0.14 6.60 0.10

Total phosphorus, mg/L 0.71 0.28 7.90 0.10

Conductivity, umhos/cm 87,452 86,480 165,000 360

Salinity, ppt 100 84 251 0

Temperature, oC 38 32 80 20

pH, SU 6.29 6.50 7.25 1.77

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Distribution of Analytical Results

0 2000 4000 6000 8000 10000 WD89A WD73A WD45A WC71D WC65JA WC53A WC237A WC215A WC173K WC170A WC168A WC130A WC110A WC102 VR22B VR164A VR119G ST34A ST164C ST161A ST148E SS58A SS191B SS189A SS182E SS182C SS169C SS157A SS108D SM40JA SM33D SM268A SM23G SM238- HI46A HI39A HI37A GI19 # 3 EI95F EI74A EI57A EI50-1 EI184A EI175B EI172A EI128A- EI107A EC49B EC47JP EC46B

BOD Value

Pla

tfo

rm

0 2 4 6 8 10 12 14 16 18

WD89AWD73AWD45AWC71D

WC65JAWC53A

WC237AWC215AWC173KWC170AWC168AWC130AWC110A

WC102VR22B

VR164AVR119G

ST34AST164CST161AST148ESS58A

SS191BSS189ASS182ESS182CSS169CSS157ASS108DSM40JASM33D

SM268ASM23GSM238-

HI46AHI39AHI37A

GI19 # 3EI95FEI74AEI57AEI50-1

EI184AEI175BEI172A

EI128A-EI107AEC49B

EC47JPEC46B

Pla

tfo

rm

Nitrate Value

BOD

Nitrate

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Offshore Discharge Regulatory Requirements

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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

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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

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EPA Region 10 - Alaska

Region 10 – Cook Inlet, Alaska

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Overview of Produced

Water Management

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

Waste Minimization – Keep Produced Water Out of the Well

Mechanical blocking devices– Packers– Plugs– Cement

Water shut-off chemicals – Polymer gels

Source: Baker HughesSource: Baker Hughes

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

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

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Physical Separation

Separation Hydrocyclone Filtration Centrifuge

Source: Natco

Source: USEPA

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Flotation

Source: Natco

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Coalescence

Source: OpusSource: Opus

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Combined Physical and Extraction Processes

Source: M-I Epcon AS Source: M-I Epcon AS

Source: Pro-Sep

Source: Pro-Sep

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Extraction

Source: VWS MPP Systems

Source: VWS MPP Systems

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Adsorption

Organoclay MyCelx Osorb

Source: CETCO Oilfield Service Company

Source: ABS

Produced Water Management Information System

http://www.netl.doe.gov/technologies/PWMIS/

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