A U S T R A L I A A R G E N T I N A C A N A D A E G Y P T N O R T H S E A U . S . C E N T R A L U . S . G U L F

Treating Produced Water For Shale Fracs

George E. KingSPE – GCS

27 October 2011

Horn River – 5000 acres accessed from a 6 acre pad

Slide Source – Brad Affleck - Apache

Starting Point: 21 Billion Gallons Per Year of Produced Water in US O&G Ops.

Produced Water is a valuable resource – not waste

Produced Brine Input Content Varies:

Salinity from 30,000 to 150,000 ppm (higher rarely)

Iron from 25 to 2000 ppm

Barium from 0 to >250 ppm

Oil carryover to 300 ppm

Bacteria from <1000 cells/ml to 109 cells/ml

Total Suspended Solids (TSS) of up to 3 to 5000 ppm, 1 to ~210 microns (70 mesh)

11/10/2011 3Water Management Presentation 13 Sept 2011

What is Needed for Slick Brine Water Fracs?

Slick Brine Water Frac

Salinity: 30,000 to ~50,000 ppm – can vary

Iron: remove suspended iron and reduce soluble iron to less than 500 ppm for oil zone fracs

Barium: reduce to <20 ppm or control scaling

Oil Carryover: less than 50 ppm, prefer < 30 ppm.

Bacteria to <1000 cells/ml – spikes to 104 acceptable

TSS: less than 500 ppm of 105 micron and larger solids

11/10/2011 4Water Management Presentation 13 Sept 2011

What is Needed for Gelled Brine Water Fracs?

Gelled Brine Water Frac Base Fluid

Salinity: 30,000 to ~50,000 ppm – constant (+/- 5%)

Iron: remove suspended iron and reduce soluble iron to less than 100 ppm for oil zone fracs

Calcium: match to needs of polymer

Barium: reduce to <20 ppm or control scaling

Oil Carryover: less than 50 ppm, prefer < 30 ppm.

Bacteria to <1000 cells/ml, add residual disinfectant

TSS: less than 500 ppm of 105 micron and larger solids

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Basic Separation

Desanders

Hydrocyclones

Flotation

Settling / Electro Flocculating

Separators / Skimmers

Membrane & Filtration

Membrane Ro, FO, ED

Filters: micro, ultra, nano

Treating Options Examined

Distillation

Pond

Mechanical vac and distill

Chemical

Chemical flocculation

Chemical precipitation

Scale out methods

Disinfection

UV

Ozone

Chlorine dioxide

Lower toxicity methods

Water Management Presentation 13 Sept 2011 611/10/2011

Equip Preference: established technology, low cost & maintenance

Remove Solids – Desander – removes TSS to spec

Remove particles to ~50 microns (100 mesh is 210 to 105 micron)

Some iron and oil will leave with particles

Remove Bacteria and Oil – Ozone or Chlorine-dioxide

No residual chemicals :removal of BTEX & oils.

No way for bacteria to develop resistance.

Needs small amount of residual disinfectant (~Cl)

Ion removal (Fe, Ba ?, Ca ?, )

Dilution with brine or brackish water input when needed.

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1st: Remove particles to about 70 microns or less.

However: Frac water does not have to be solids free…..

Sand (proppant) has 0.5 to >3% smaller than spec particles

Gelled fluids have microgels – even “liquid” polymer.

Protect large pores & nat. fracs in conventional reservoirs.

In shales, it’s a different game.

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Bacteria Alone

UV – top choice

Ozone – 2nd

choice

Chlorine Dioxide –3rd choice

Glutaraldehyde

Quaternary Amines

Ultra & nano filtration

Membrane

Top choices minimize chemicals, maintenance and cost.

2nd : Bacteria and Oil Reduction

Bacteria & Oil

Hydrocyclone with UV or other after treatment.

Water Management Presentation 13 Sept 2011 9

Oil (Alkanes & BTEX)

Hydrocyclone –first choice

Skimmers in larger oil ppm cases – 2nd

choice

Ozone & ClO2

Micro and ultra filtration

11/10/2011

Ungelled? (slick water frac)

Sulfates where Ba or Sr is an issue.

Surfactants?

Does water recovery really help?

Can water retention really be an advantage?

Do capillary blocking forces work to keep natural fractures and fissures open?

3rd – What else is needed? – a lot of questions…

Gelled? (linear, hybrid, etc.)

Ion Control

Fluid consistency (can it be mixed?)

Scale potential? Worth treating?

Surfactants?

Other Chemicals?

Oxygen scavengers? – watch biocide and scale inhibitor interactions

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Brine Sources

Brine Source Well – 30,000 to 50,000 feed stock, low bacteria and acceptable mineral composition.

Flow rate (quantity) not always sufficient

Produced Water

Slip stream of produced water re-injection

Produced water for disposal

Frac flowback – often low preference because of amount of treating required.

Bacterial content variable and increasingly high -

Returning chemicals (mostly polymer)

Often higher salt content

Problem ions – Barium, Radioactive ions (rare), heavy metals

Other – treated gray sewage water, acid mine drainage, industrial waste – not at this time for most areas.

11/10/2011 11Water Management Presentation 13 Sept 2011

Water Descriptor

Total Dissolved Solids

(TDS) in parts per million (ppm)

Fresh <1000 ppm

Brackish 1,000 to 5,000 ppm

Highly Brackish

5,000 to 15,000 ppm

Saline 15,000 to 30,000 ppm

Sea Water

30,000 to 40,000 ppm

Brine 40,000 to 300,000+ ppm

Produced and Brine Water Sources

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Water can definitely be too dirty……

Water freshening via Reverse

Osmosis, evaporation, nano

filtration, etc., is increasingly

uneconomic as salt content

increases.

Produced Water as a Resource – Closed Loop Fracturing

Produced Water is No Longer Waste

Best Recycle Water?– Moderate salinity, low solids, few chemicals.

Keep water streams separate until you know what is needed.

Most chemicals are removed in the formation through adsorption, “spending”, or precipitation.

Polymer often returned. How to remove?

Bacteria – often biocide resistant – increases with amount of recycling. Special methods required.

Best frac water? Brine from a dedicated brine source formation or large volume water flood with few chemicals

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How it might fit together

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Other Issues

H2S in water – treating extra

Quality of brine source well – supply and composition

Special requirements for chemical addition

Pipeline vs. Truck Transport of treated water to alternate storage or well

Grouping of well activity to locate treating facilities

Remote well treating – skid mounted equipment

Power requirements.

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Economics and Conclusions

Economics vary with:

Level of treatment

Ownership vs. rental

3rd party (disposal well charges)

Area specific water source quality

Frac fluid base water requirements

$0.20 to $1.00 / bbl target cost for OPEX (maintenance and Operation)

Estimated CAPEX cost $1mm

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Year % OGIP

Recovery

(OGIP = original

gas in place)

Technologies Applied Shale in

Development

Average

gas price

$/mmbtu

1980’s 1% Vertical wells, low rate gel fracs Devonian $1.98

1990’s 1.5 to 2% Foam fracs 1st slick water in shale Devonian $1.91

2001 2 to 4% High rate slick water fracs Barnett $4.25

2004 5 to 8% Horizontal well dominant, 2 to 4 fracs Barnett $6.10

2006 8 to 12% Horiz, 6 to 8 fracs, stimul fracs, water

recycle trial

Barnett $7.25

2008 12 to 30% 16+ fracs per well, Petrophysics

increases

Barnett $9- drop

2010 30% to 40% Technology to flatten decline curve,

feeling pinch for frac water

Haynesville $4.20

2011 45%+ Pad development drains 5000 acres, salt

water displacing fresh for fracs

Horn River $4.00

Future project 45 - 55% Green chemicals, salt water fracs, low

disposal volume, reduced truck traffic,

pad drilling, electric rigs and pumps

Numerous Depends

on market

Source: King, SPE

152596

Shale Technology Drivers

HRB Water Delivery – 67-K Site

18

• Lined pit was added in 2011 to allow plant to stay running

• Additional water source well brought online due to APA water demand

• Backup fresh water system has been used on all pads so far

0

5000

10000

15000

20000

25000

M3

/day

Fresh Water Debolt Water

Pit & 3rd

Source Well In Service

Plant Online

100% Fresh Water

HRB Water Delivery – Water Delivery

19

34-L

91%

63-K

54%

76-K

97%d-1-D

97%

70-K

0%

Conclusions

20

• Fracturing with saline water is possible, economic

and production results are promising…..

• Brine source frac water is 0.25% to 50% of fresh

water costs in some cases.

• Cost of treating produced water for fracs is THE

major factor – target is $0.25 to $0.50 per bbl.

• There is a balance between water sources and

source locations. Emissions and other problems

with truck traffic will be a major factor.

• Using non potable water when possible makes

sense and highlights the environmental

responsibility that Apache values