# A Closed Loop System Using a Brine Reservoir to Replace Fresh Water as the

Frac Fluid Source Minimization of Fresh Water Use: The Use and Reuse of 35000 ppm Brine from a Dedicated Deep Reservoir as a Fracture Fluid For Shale



# George E. King Apache Corporation EPA Workshop on Hydraulic Fracturing March 29/30, 2011

# Acknowledgements
• EnCana – water plant operator and lead company on testing of Debolt water. • Dave Sherman (formerly Apache facilities) – plant design, water handling solutions, emissions reduction, natural gas substitution 

# for Diesel fired engines in pad operations.

Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 2Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 3

# A Unique Frac Water Source
• Debolt formation, above the Horn River Play (British Colombia, Canada) • Water

– 35,000 ppm TDS

– H2S (10 to 30 ppm ?) removed prior to use

– Temperature of 60C (140F) (useful for cold weather operations) 

# • Minimizes water storage needs • Minimizes fresh water requirements • Flow back returned to the Debolt formation. Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 

### Dave Sherman, Apache Canada, 2010 4

# Cold Weather Water Pumping Intrinsic Heat Load for 10” Thin Wall Aluminum Pipe, - 25 C Water at high rates has enormous specific heat capacity. If water is kept moving it can be pumped long distances in cold weather without freezing or heat input.

Water specific heat capacity at 16,000 m3/day, 2 Degrees C What happens when the water stops moving? Large diameter water piping is a must for cold climate water pumping! Large diameter piping makes it possible to address equipment failures prior to piping freeze offs. 10" AL Pipe Time to Freeze 1.0 Length m 50.7 kg water 2.0 Temp Water
-21.2 minutes 6" AL Pipe Time to Freeze 1.0 Length m 18.2 kg water 2.0 Temp Water
- 10.3 minutes 12" AL Pipe Time to Freeze 1.0 Length m 73.0 kg water 2.0 Temp Water
-27.5 minutes Daily Water Volume Transferred 16000 m3 Water Volume Tm 5 Deg C Water Temp Water Vel 3.6 m/s Water Velocity ID 25.4 m Pipe ID Tamb -25 Deg C Air Tamb Air Vel 1.4 m/s Wind Speed Water Kin Vis 0.000001519 m^2/s Kin Viscosity k 0.609 W/(m Deg C) Thermal Cond Pr 11.57 Prandtl Number Water near zero Reynolds Number UmD/v 601974.9835 Inside Film Coefficient hi =(Nu)*k/Di 4832.525724 W/(m^2*Deg C) Outside Film Coefficient ho =NU*k/Do 14.02886245 W/(m^2*Deg C) Overall Heat Transfer Coefficient U =1/(1/hi+1/ho) 13.98825443 W/(m^2*Deg C) Intrinsic Heat load Heat Loss Per Meter Pipe Q =A*U*Delta T 334.8639279 W/m Water Specific Heat Capacity 4.21 kJ/kg*K Delta T 2 Deg C Mass Flow 11000 kg/min 1543666.667 =Joule/sec Meters to Freezing 4609.83 m Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 5

# Before: Off lease Remote Water Heating 8 o 

# C @ 100 bbl/min – > 30 MMBTU/hr

Tight lease space on the d -70- K Pad and LPG fuel storage regulations required an off lease water heating solution creating the following special challenges: Conventional methods were to heat bulk water storage reservoirs typically on lease, not provide instantaneous energy input fo r 8 C water heat rise at 100 BBL / min Size and type of heat exchanger required for water flows at 100 – 125 bbl Slipstream and Mix Flows Apache Solution to Enable Compact Portable Heat Exchange of 30,645,580 BTU / Hour Heat losses in 1,000 m of 12” piping at - 25 C

Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 6

# Water Management
• Large volumes of fresh water not required. • Recycling frac & produced waters • Higher salinity sources are now usable. • Chemical Management is Essential

– Biocides under the microscope • Greener (bio - degradable and no bioaccumulation)



# – Lower vol. of chemicals (what’s really needed?)
Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 7

# Brackish Water Source for Fracs
• High perm sand w/ 35,000 ppm, sour (H 2 

# S) brine is present ~ 2,000’ above gas shale target zone. • Brine can be supplied at high rate to the treating facility for sweetening and then to the frac spread for pumping. • Flowback water is cleaned and re - injected. • Advantages:

– Fresh water use is cut to a minimum.

– High Cl - 

# brine eliminates or reduces many chemicals

– Surface storage of frac brine is <<5% of job volume.

– Higher salinity brine stabilizes shale?

– The hot water from the reservoir eliminates very expensive water heating need and eliminates air emissions from the heater

– Cheaper than fresh water for development of multi -well pads

– Lowest Environmental Impact and Smallest Foot Print Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 8

## • 2009 Capital spending to be minimized where possible •Apache completions to begin October 2009 • Design for average of 3 Fracs a day with enough water for goal of 4 ~ 4,000 m3 fracs per day 

## • Lowest environmental impact and smallest footprint possible • Repairs to water system can be performed in a timely fashion using local stock parts • Follow all of Apache and Encana’s EH&S regulations, ensure safe handling of water 

# Moderate Salinity Brine Supply for Frac Water

Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 9

# SPE 138222, Pond, et al., (EnCana)

Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 10

# Getting away from fresh water use – Saline Water Supply Schematic

77- K Non Potable Water Source Well

Mercaptan Scavenger & PH Buffer



### ACL d -70- K Well Pad Fresh Water Make - Up 67- K Plant Inlet Separator Fresh Water Lake 

### C-67- K/94-O-08 Etsho Compressor Station & Water Plant Site Borrow Pits For Freshwater Storage Only

67- K Non Potable Water Source Well



### ACL d - 52- L

Well Pad Produced Shale Gas & Fracture Stimulation Flowback Water Treated Non Potable Source Water for Fracture Stimulations Separator Vessels & Treated Water Storage Tanks

90-J Non Potable Water Disposal Well Debolt Reservoir (ASR) Non - Potable Aquifer Storage Reservoir Produced Natural Gas to Spectra Sales Tie- In Produced Fracture Stimulation Flowback Water

* Closed system, no storage of treated water in un - lined burrow pits. * Water Recycle Line, Stimulation Flowback Water Compatibility Under Review 

## Minimal Use

Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 11

# Debolt Water Analysis

Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 12

# Flow Back vs. Time

3 bbls/minute

Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 13Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 14 

## Flowback water from a shale frac. The yellow color is from iron in contact with oxygen from the air. 

# Slight adjustment to pH results in a clear solution. Background salinity varies with the shale.Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 15 

# Ion variation in the backflow

Matt Blauch , SPE

# Conclusions
• Debolt source water is from a regional sour aquifer with a TDS level 

# unsuitable for either agriculture or drinking water. • Use of Debolt water required a series of tests focused on water treatment, formation interaction and disposal potential. • Environmental impact improvements are seen in a number of areas:

– Closed loop system – no oxygen and minimal flare/venting.

– Minimize water heater emissions using hot Debolt water (~140F/60C) to prevent freezing in the - 20C operations.

– Minimize fresh water usage - still used in surface drill & cementing.

– Possible reduction of biocides & elimination of some other chemicals.

– Reduce surface frac water storage to <<5% of total needed

– Reduction of surface pipe & draw from lakes.

– Reduction of truck traffic and roads by using the closed - loop system. 

# • Pad design (16 wells on 6.3 acres drains >2500 acres). Sharp reduction in roads, pipelines, facilities and traffic. • Possible shale stability improvements with more saline water. Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 16

# Support Slides
• Forward Osmosis Clean - Up • Water Districts and Plastic Pipe Supply Lines • Types of Treatment

Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 17

# Cleaning Up Drilling Fluids Water treated by 

# forward osmosis is not fresh water – it is a clean saline base fluid that can be used for fracturing. Salinity of the water delivered by FO can 

# be programmed.

18 Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011

# Water Districts
• Flexible (e.g., HDPE) pipes – surface or subsurface to transfer water to and from wells without truck traffic.

Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 19Minimizing Fresh Water Usage, George E. King, EPA 29/30 March 2011 20