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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
11/10/2011 5Water Management Presentation 13 Sept 2011
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.
11/10/2011 7Water Management Presentation 13 Sept 2011
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.
11/10/2011 8Water Management Presentation 13 Sept 2011
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
11/10/2011Water Management Presentation 13 Sept 2011 10
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
11/10/2011Water Management Presentation 13 Sept 2011 12
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
11/10/2011 13Water Management Presentation 13 Sept 2011
How it might fit together
Water Management Presentation 13 Sept 2011 1411/10/2011
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.
15Water Management Presentation 13 Sept 2011 11/10/2011
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
16Water Management Presentation 13 Sept 2011 11/10/2011
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
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