underbalanced drilling

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UNDERBALANCED DRILLING

UnderbalancedDrilling



Emerging technologies are revolutionizing compressible

drilling fluid systems.

UnderbalancedExperience



For successful utilization of these exciting new technologies, a

professionally engineered team approach is essential.




Potential cost savings and increased production warrant consideration of

drilling underbalanced.




Weatherford’s experience and expertise will assist you in investigating whether the use of

compressible drilling fluid systems is the most efficient process for reducing your

drilling and stimulation costs.

Underbalanced Experience



Benefits

Underbalanced Drilling

• Optimize reservoir performance

• Minimize costs and risks

• Increase drilling efficiency through rates of penetration

• Reduced formation damage

• Because you “MUST”



Weight ofDrillingFluid

Weight ofDrillingFluid Formation

PressureFormationPressure

Terminology

“Compressible Fluid Drilling” (CFD) is defined as the use of techniques that employ gases to reduce the density of a drilling media.



• Provide Integrated, Technology-Driven

• Underbalanced Services

• Push the Envelope of Technology

• Maximize Well-Site Efficiency and Integration by Providing Multiple Products and/or Services

• Create Alliances with Strategic Industry Partners

Weatherford's Goals in Compressible Fluid Drilling Include:

Weatherford's Goals in Compressible Fluid Drilling Include:

Direction



What services does Weatherford provide?What services does Weatherford provide?

Services

• Compressible Fluid Drilling

• Specialized Compressible Fluid Drilling Additives - FOAM

• Hydraulics Software for Multi-Phase Flow

• Data Acquisition

• Engineering of Technical CFD Applications

• Air Compression

• Nitrogen Services

• Specialty Drilling Equipment



Testingand Training Rig

• OIME Model 950E• Well Depth = 1,468 ft.• 1000 hp Draw works• 450,000 lbs. pull limit• 6-5/8”- 30 drill pipe power

tong• Push Master™ tong

positioning• 16K Power Tong w/Power

Scope• Stabmaster™ Stabberless

System



Rig

CompressibleFluid Drilling

Team

CompressedGases

ProjectManagementandPlanning

DrillingFluidsChemistry

CompressibleFluidHydraulicSimulations

DataAcquisition

SpecialtyTools

Percussion Drilling

Systems

Back EndSeparation

DirectionalServices

Services



• Texaco -- High Pressure Coal Cavitation.

• Shell -- Trans-Foam drilled laterals in low pressure Shale.

• PDVSA -- Project Engineering, Closed System Underbalanced.

• PEMEX -- UBD Candidate Selection, Well Planning

• YPF -- Project Management, Foam Drilling, Formation Evaluation while Drilling

• Baker Inteq -- Fluids Services, Engineering, and Training for Offshore CT Drilling.

• MOBIL -- Complete Underbalanced Drilling System -- Engineering, DAQ, Compressed Air, Nitrogen Services, Fluids.

• PetroBras -- Engineering, Design and Fluids Management for Low Head Drilling Research Project. Salvador, Bahia.

• Texaco -- High Pressure Coal Cavitation.

• Shell -- Trans-Foam drilled laterals in low pressure Shale.

• PDVSA -- Project Engineering, Closed System Underbalanced.

• PEMEX -- UBD Candidate Selection, Well Planning

• YPF -- Project Management, Foam Drilling, Formation Evaluation while Drilling

• Baker Inteq -- Fluids Services, Engineering, and Training for Offshore CT Drilling.

• MOBIL -- Complete Underbalanced Drilling System -- Engineering, DAQ, Compressed Air, Nitrogen Services, Fluids.

• PetroBras -- Engineering, Design and Fluids Management for Low Head Drilling Research Project. Salvador, Bahia.

Many well-known companies depend on Weatherford's expertise in compressible fluids

drilling.

Many well-known companies depend on Weatherford's expertise in compressible fluids

drilling.

Service



Accomplishments

• World’s Only Patented Recyclable Foam System -- Trans-Foam

• Foam to 1500 meters Horizontal Reach

• Foam With 70% Oil Contamination

• Foam to 22,000 ft Depth

• AMFM Down-hole Model, Proven Effective at 55-100% GVF (Gas Volume Fraction)

• Horizontal CT Drilling with Foam in

• Depleted Oil Reservoirs

• Unparalleled Worldwide Experience in

• Technical CFD Applications



Formation Damage

Fracture Plugging

Pore Plugging Skin Damage

• Reduction of relative permeability

• Plugging of pore throats by fine cuttings

• Swelling of water sensitive clays

• Damage by contact with foreign fluid



UnderbalancedChemistry

• Surfactants (Foamers)

• Shale-Control Polymers

• Corrosion-Control Additives

• Water Shutoff Chemistry

• Special Gas Entrainment Chemistry



Foam offers the greatest cutting-carrying capacity of all drilling fluids.

Foam offers the greatest cutting-carrying capacity of all drilling fluids.

Increasing Cutting Carrying CapacityDecreasing Velocity RequirementsIncreasing Cutting Carrying CapacityDecreasing Velocity Requirements

CompressibleDrilling Fluids



• Quality (100) 100% Gas

• Least Efficient Transport Medium

• 3000 ft/min is Adequate

• Velocity Required Changes in Horizontal Section

• Dry Air is Rarely Dry

Dry Air & Gas



• Quality ( 96 - 99.9 % )

• 30% More Air Required “NO”

• Water Phase is Continuum

• Physically Resembles a Fog

• Surfactant lowers fluid surface Tension

• Better Definition: Ultra High Quality Foam

• Fluid Droplets Considered Cuttings With Slip Velocity



Foam

• Quality ( 55-99.5%)

• Most Efficient Medium (velocity)

• Lowest Slip Velocity

• Most Versatile

• Widest Effective Quality Range

• Present up to 99.5% Quality



BULK FLUID

GAS

Surfactants (Foam)

• Select Carefully

• Provides Great Cuttings

• Transport

• Low Annular Velocity

• Hydrocarbon Tolerance

• Salt Tolerance

• BHP Vs Friction



120 o

GAS

PHASE

DRAINAGE IN THE LAMELLA

FILM ELASTISITY

BULK DENSITY

SURFACTANT SELECTION



BULK FLUID

FOAM

GAS

120 o

GASPHASE

Thin Film

Region

(Liquid Phase)

Interface(2-D Surface Phase)

Plateau Border

Lamella

Surfactants(Foam)

• Select Carefully

• Provides Great Cuttings

• Transport

• Low Annular Velocity

• Hydrocarbon Tolerance

• Salt Tolerance

• BHP vs Friction



Aerated Fluid

• Quality (0-55) 0-55% Gas

• Extremely Inconsistent Medium In High Quality Range

• Fluid And Gas Have Very Different Frictional Factors

• Adding Gas to Standard Mud is Not The Solution

• Special Entrainment Chemistry Benefits



Trans-Foam®

• World’s Only Recyclable Foam

• Most Oil-Tolerant Foam Available

• Reduces Chemical Costs

• Reduces Water Consumption

• Provides Substantial Waste Reduction



Trans-Foam®

• First Well, Basilacata, Italy, Texaco, 1992– 1,500 feet of 26” Hole– 4,500 feet of 17.5” Hole– Set Drilling Records for the Area

• Most Recent Well, September 1999– PDVSA Lake Maracaibo, Venezuela – Offshore Location -- Containment Critical– Highly Successful 300 meter Laterals– Oil Influx– Ten days of Circulation with only 500 Barrels of

Water Consumption



Separator

Shaker, Low pHCirculating System

pH Control System

Recovered Solution Ready for Re-Use

CompressionEquipment

Typical Trans-Foam®

Layout



Shale-Control Polymers

• Shale Hydration -

• Big Problem

• High Shear at Bit with Gas Drilling

• Compatibility with Foamers

• Decrease Shale

• Sloughing and Increase

• Hole Stability



Corrosion Chemistry

• Always a Consideration

• Accelerated with CO2 or H2S

• Potential Exists for Temperature and Pressure Increase

• “Erosion Corrosion” in Lateral Wells

• Easily Handled with Proper Chemistry



Source: US DOE, Oil & Gas Journal Sept. 23, 1996

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

35.0%

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Per

cen

tag

e o

f A

ll W

ells

02000

40006000

800010000

1200014000

Nu

mb

er o

f W

ells

Percentage of All WellsNumber of Wells

Underbalanced Drilling ActivityUS Activity - 1994 - 2005



Compressible Fluids Gas Injection

• Air Nitrogen Or Natural Gas

• Inject Down Drill String

• Install Parasite

• Scab Liner Or Concentric Pipe



Air-Nitrogen Injection(Down Drill String)

• Simplest Application

• Most Cost Effective

• Hard To Control Bottom Hole Pressure While Tripping

• Use Steering Tool Or EMWD



Parasite String

• More Expensive Installation

• Controlling ECD is Limited By Depth of String

• Good Control of BHP While Tripping

• Allows Mud Pulse



Scab Liner

• Expensive Installation

• Limited In Controlling ECD By Depth Of Setting

• Control Of BHP While Tripping

• Allows Mud Pulse



Weatherford manufactures a

complete line of compression

equipment designed to optimize

performance.

Weatherford manufactures a

complete line of compression

equipment designed to optimize

performance.

Compression Equipment



Weatherford maintains complete control during all construction phases of compression equipment.

Weatherford maintains complete control during all construction phases of compression equipment.




Quality starts at the design stage, and is built in throughout the manufacturing process.

Quality starts at the design stage, and is built in throughout the manufacturing process.




In-house manufacturing facilities help control quality, cost and lead time.

In-house manufacturing facilities help control quality, cost and lead time.




Shown, are Weatherford high-pressure membrane nitrogen modules and control panel.

Shown, are Weatherford high-pressure membrane nitrogen modules and control panel.




High-pressure air flows in, and the resulting output is high-pressure, high-purity nitrogen.

High-pressure air flows in, and the resulting output is high-pressure, high-purity nitrogen.




Reliable Weatherford compressors are “on-the-job” at sites around the world.

Reliable Weatherford compressors are “on-the-job” at sites around the world.




Compressor- Booster Combination

Compressor- Booster Combination

Fuel Consumption - 22 gal/hrLowest in the Industry!

Fuel Consumption - 22 gal/hrLowest in the Industry!




Compression/ Nitrogen Membrane

Unit

Compression/ Nitrogen Membrane

Unit

Nitrogen Compression Equipment



Rotating Control Heads

• Williams rotating control heads are known worldwide for well control and other uses when drilling for oil, gas, coal bed methane, and geothermal resources.

• Williams model 7000 series control heads are designed to operate at the higher pressures of horizontal and reverse circulation drilling applciations. Rotary or top drive capable, bearing assembly change-outs can be made without removing the drill string from the well. This exclusive system also permits very quick stripper rubber change-outs or the total replacement of the bearing assembly in minutes.



Rotating Control Heads

• Dual Rotating Stripper Rubbers

• Water Cooled Seals

• Positive Oil Lubrication

• Hydraulic Operated Clamp

• Complete System



Data Acquisition

• Extremely Important

• Historical Data Enhances Future Operations

• Required for Sound Engineering Decisions

• Provides Electronic Record of Well



Data Acquisition

• Measure and Record– Pressures– Rates– Gas– Liquid– Temperatures

• Real Time Display

• Proprietary Software - Industry’s Finest

• Software Designed to Provide Dynamic Data Exchange with Multiphase Flow Model -Weatherford is the Only Company in the World to Offer this Capability



Data Acquisition



Multi-Phase Hydraulics ModelMulti-Phase Hydraulics Model

AMFM Model

• Developed by Clearwater and Penn State University

• Designed by Field-Trained Engineers

• Most Accurate Model for Two and Three-Phase Flow

• 7 Years in Development

• Not Designed For Commercial Use

• Used as a Tool to Ensure Success in the Field

• Updated Continually with Accurate Field Data



Count on Weatherford's Experience and Expertise to

Maximize Productivity on Your Next Drilling Project.

Count on Weatherford's Experience and Expertise to

Maximize Productivity on Your Next Drilling Project.

For All Your Drilling Needs

The Complete Package

underbalanced drilling

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underbalanced drilling weatherford

underbalanced experience

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compression equipment

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