Making our planet more productiveSM

Economical, Efficient, EffectiveUsing Carbon Dioxide for Gas Well Fracturing

Energy

The ability to develop a wider array of naturalgas reservoirs has become central to meetingtoday’s energy needs. This has become criticallyimportant as we not only exploit historic conven-tional gas reserves, but also move into uncon-ventional gas deposits (coal bed methane, tightsands, and shale gas) which are becoming anincreasing percentage of our energy supply mix.To facilitate unlocking of these unconventionalgas deposits, energy companies are increas-ingly depending on hydraulic fracturing.

Praxair has been serving the oil & gas marketsfor over 30 years. We offer targeted productsand services to the well services industry tosupport fracturing throughout North America,Brazil, and China. We supply liquid CO2, trans-portation and logistic services, and primarypressure pumping. We also operate a numberof strategically located plants, a specializedfleet of vehicles, and dedicated pumpingequipment. Depending on your geography,Praxair is able to provide complimentary nitro-gen services to meet your oilfield needs throughan extensive network of subsidiary and jointventure partners.

www.praxair.com

Gas Well Fracturing

Solubility and Viscosity – Used extensively since 1962 as an additiveto acid fracturing, CO2 is very soluble with oil and water. Due to itssolubility, it greatly reduces viscosity (especially of oil) during afracturing treatment.

Less Damaging – An advantage of using CO2 is its low pH (4.5 to 5.0).In formations where clays are usually found, using CO2 with the fracfluid minimizes the swelling of these clays, allowing the sand ladenfluid to penetrate farther into the fractures. CO2 is also less damagingto water sensitive and low pressure formations.

Easier Cleanup –When using CO2 fracture treatments far less water isintroduced into the formation compared with traditional frac treatments.This results in significantly less liquid to clean up and less liquid trappedin the formation by capillary forces. Additionally, the high percentageof CO2 lightens the fluid column in the well bore reducing the energyrequired to remove the frac fluids. The expanding CO2 also providesmuch of the energy needed to remove the fracture fluids and excess sand.

This results in faster, more thorough, and more economical cleanup aswell as accelerated well production startup.

No Special Equipment Required – The use of CO2 can be an addedadvantage for service companies and well operators because, withvery limited modifications, the same equipment can be used to pumpthe high pressure CO2 as they would use to pump water.

The Benefits of Using Carbon Dioxide

Fracturing Simulation

WellHead

PraxairCO2

Vessels

Praxair PumpTrailer

WaterTanks

Excellent Supply PositionsPraxair has one of the largest supplies ofCO2 in the US. We are based where youneed us and can be therewhen you need us.

The Leader in Delivery andPortable StorageIn the last three years Praxair has addedalmost 3,500 tons of portable storage tohandle the increase oil and gas servicedemand for liquid CO2 We currentlyhave approximately 200 portable storage

tanks available (ranging in size from 34to 60 tons each in capacity), as well as1,080 tons worth of skid mounted tanks.

To fill these portable vessels, we haveover seventy 20 ton transport trucks inservice. Our fleet includes two specialCO2 trucks that can haul 10 tons apieceup mountainous roads or other areas oflimited maneuverability.These two truckscan also be used on location to providethe boost pressure to the high pressurepumps used to pump CO2 down hole.

We have a number of skid mountedplants, rated at 300 tons per day. Theseplants are portable and can be set up in daysin conjunction with skid mounted tanks.

Another valuable resource is our sub-stantial network of railcars.With over 350in operation, each capable of transporting80 tons of CO2, we are able to expandfar beyond the normal reach of usingtrucks alone.

The Leader in Logistics andOnsite Pumping ServicesPraxair provides portable storage andCO2 on the jobs sites, and can managethe boost pump operations as well. Inorder for service companies to pump theliquid down hole at a steady rate, smallboost pumps with capacity ranging from10 barrels per minute to 100 barrels aminute must be used. Praxair can providethis service, along with the necessaryexperienced technicians to help ensurereliable fracture treatments and to preparethe infrastructure.

Our newest boost pumps are automatedso the operator can be at a safe distancefrom the high pressure lines when oper-ating this piece of equipment. With thenew pumps we can also capture boostpressure and flow rate digitally for latercomputer analysis.

Why Choose Praxair

In one of our more complex assignments, we recently performed a frac job within theAppalachian basin in Alabama.

We were able to move and pump 2700 tons of CO2 in four days. We initially filled1450 tons of portable storage from the Loudon, TN, Decatur, AL, and Brandon, MSplants.We also were able to obtain an additional 1200 tons of storage within railcarsplaced 20 miles from the location. Each railcar was capable of hauling 80 tons.In one day, we moved 720 tons of product, enabling us to pump the next day’s stageof 600 tons.

A Frac Story

US Natural Gas Reserves by Area

© Copyright 2008 Praxair Technology, Inc.All rights reserved

Praxair, the Flowing Airstream design, andMaking our planet more productive, aretrademarks or registered trademarks ofPraxair Technology, Inc. in the United Statesand/or other countries.

The information contained herein is offeredfor use by technically qualified personnel attheir discretion and risk without warranty ofany kind.

Printed in the United States of America04/08

Printed on recycled paperP-10063

Praxair, Inc.39 Old Ridgebury RoadDanbury, CT 06810-5113USA

www.praxair.cominfo@praxair.com

Telephone:1-800-PRAXAIR (1-800-772-9247)(716) 879-4077

Fax:1-800-772-9985(716) 879-2040

1 BBL LIQ

1 TON LIQ

1 GAL LIQ

1 CF LIQ

BBL LIQ

1

5.45

0.0238

0.178

BL GAS

560.9

3.057

13.4

99.6

LBS

366.5

2,000

8.72

65.27

Physical Properties of Carbon Dioxide

Typical Properties of Carbon Dioxide

SCF GAS

3,151

17,168

75.02

559

GAL LIQ

42

229

1

7.481

Density Liquid 65.3 Lb/Ft3 @ -10°F, 250 PSIG

Density Gas 44.7 Lb/Ft3 @ -170°F, 4000 PSIG

Triple Point (Forms Dry Ice) -69°F, 60.43 PSIG

Critical Temp (Exists As Gas) 87.8°F

Critical Pressure (Exists As Gas) 1051.6 PSIG

Critical Density 29 Lb/Ft3

Latent Heat Of Vaporization 125 Btu/Lb @ -10°F

Solubility In H2O 170 Scf/Bbl @ 170°F, 4000 PSIG

Viscosity Gas 0.015 Centipoise @ 0°F

Viscosity Liquid 0.085 Centipoise @ 0°F

SCF GAS MEASURED @ 14.7 PSIA & 60°F (1 lb of LCO2=8.569 SCF OF GCO2) LIQUID CO2MEASURED @ 250 PSIG & -10°F

CF LIQ

5.616

30.64

0.1337

1

Praxair is a Fortune 300 company with sales of over $9 billion. We’re one of the largest companiesin the world – and the largest in North and South America – specializing in industrial gases. Weoperate in 40 countries worldwide, serving one million customers and a wide range ofindustries, including energy, manufacturing, chemicals, metals, healthcare and more.

To learn more about Praxair’s CO2 gas well fracturing services, go to www.praxair.com or call303-619-0121 or 307-871-2007.

A Global Leader in Industrial Gases