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2© 2006 Weatherford. All rights reserved.

Propellant Stimulation

Weatherford wireline services provides a comprehensive package of casedhole logging-and-completion services including production logging, thru-

casing and thru-tubing reservoir evaluation, casing/ tubing inspection,

pressure control, propellant stimulation, perforating, pipe recovery, cement

evaluation, and tubing-conveyed perforating.

Cost-effective well cleanup

Weatherford’s propellant stimulation services provide cost-effective

solutions for cleaning up wells and evaluating interval potential.

Propellant stimulation services are used to treat zones with drilling,cement or perforation damage. Propellant stimulation services also

initiate formation breakdown to aid hydraulic fracturing by removing

and/or reducing tortuosity.

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Weatherford propellants aredeployed into the well with

wireline or tubing.

Propellants are positioned over

the zone-of-interest and ignited.

Gases generated by the dea-

gration exert a pressure load on

the formation that is less than the

compressive yield strength of the

formation rock. As burn pressure

increases, short fractures are

created in the formation. Fracturegrowth is maintained by con-

tinued gas generation from the

tool burn. Once the tool is spent,

differential pressure creates a

surge into the wellbore, back-

ushing the near-wellbore region.

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Propellant StimulationTool (PST)

The PST is used in previously

perforated or open-hole applica-

tions where tubing has been

removed from the well. The PST

is typically run in a specially

congured, perforated carrier

that protects the propellant. The

tool’s cast propellant cylinder is

equipped with a central detonat-

ing cord ignition system.

StimTube™ Tool

Although similar to the PST in

its external conguration and

ignition method, StimTube tool

is congured for through-tub-

ing applications where an

external protective carrier

cannot be run. StimTube tool

contains a perforated support

tube that adds rigidity and

ruggedness to the propel-

lant. The support tube does

not interfere with propellant

ignition.

StimGun™ Assembly

The StimGun assembly

perforates and stimulates the

well simultaneously. StimGun

assembly places a cylindrical

sleeve of propellant over a

specially congured, perforat-

ing carrier. The pressure wave

generated by the perforating

charge ignites the propellant.

Gas from the propellant enters

the newly created perfora-

tions, breaking them down and

stimulating the formation.

Horizontal StimulationTool (HST)

Weatherford’s horizontal stimula-

tion tool (HST) was specically

developed for superior propellant

stimulation of long horizontal or

vertical intervals and simultane-

ous stimulation of multiple inter-

vals. The ignition train is designed

for highly reliable performance,

ensuring that the complete length

of the HST assembly ignites. The

modular conguration of the HST

assembly allows tool sections to

be pre-built for easier handling

and fast assembly as they are run

in the hole.

Specifcations

Diameter .............1 1/2 - 3 1/2 in.

................................. (38-89 mm)

Length ...........................Variable

Max. Temp.1.........220°F (104°C)

Max. Pressure .............Unlimited

Specifcations

Diameter .............1 1/2 - 3 1/2 in.

................................. (38-89 mm)

Length ...........................Variable

Max. temp.1 .........350°F (177°C)

Max. pressure .............Unlimited

Specifcations

Diameter ...................3 1/2 - 5 in.

.............................. (89-127 mm)

Length ........................... Variable

Max. temp.1 .........350°F (177°C)


Specifcations

Diameter ............1-11/16 to 2-1/2

..........................42.9 to 63.5 mm

Length ...........................Variable

Max. temp.1 ........... 220°F 104°C


Carrier diameter .........................

........................2-1/16 to 3-3/8 in.

..........................52.4 to 85.7 mm1 Propellant remains stable above this temperature but may become pliable.

In order to achieve an efcient propellant burn and to ensure the stimulation gases are held over the interval

a minimum uid column height of approximately 1,000 ft. (300 m) is required over the tool.

Tool connector

Ported carrier

Propellant

Propellant

Perf. supporttube

Tandem

connector

Retainer ring

Shaped charge

Propellant

sleeve

Perf. carrier

Tool connector

Perf. carrier

Propellant

cylinder

Control line

Bottom

connector

Finned top sub

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PulsFrac® computer modeling

PulsFrac computer modeling is critical to effective propellant-stimula-

tion design.

PulsFrac computer modeling software calculates and displays the

effects of a proposed propellant stimulation upon a well so tools can be

congured to minimize risks and maximize the effectiveness of actual

stimulations. PulsFrac computer modeling also predicts the dynamic

effects of rock-fracturing pressurization on the formation as well as the

motion of uids within the wellbore.

After actual stimulations are complete, engineers compare PulsFrac’scomputer modeling with actual job pressure data to assess the effec-

tiveness of the treatment.

Propellant modeling

The model (below) is effec-

tive at estimating the pressure

response and fracture length

generated during a stimulation

application. The data from the

model can be used for compari-

son to high-speed pressure data

obtained during a stimulation.


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High-speed pressure recording

Weatherford records stimulation pressure data at a high speed of over

100,000 samples per second. The data is used to determine the effect

of the actual stimulation upon the formation. Engineers create propel-

lant burn proles that estimate formation breakdown pressure and

closure stress. Propellant burn proles also can provide rough

permeability estimates.

The recorder is shock-hardened to withstand the effects of high-im-

pact dynamic events. It also can monitor perforating events.

Fracture Closure

Time (sec)

-0.050.00 0.10 0.15 0.20 0.25

P r e s s u r e ( M P a )

120

100

80

60

40

20

0

Tool 3 Ignition(Spike Masked by adjoining tool)

Burn Ends @ 0.088s69.8MPa (10,125psi)

Tool 1 Ignition (Top)

Tool 2 IgnitionTool 4

Ignition

(Bottom)

Pressure vs. Time

This presentation (below) of

high-speed pressure data was

recorded during the simultaneous

stimulation of four intervals in a

horizontal well. The stimulation

was run to assist formation break-

down after a previously failed

hydraulic frac attempt. The

ignition of the individual tools

is clearly evident.

“ Weatherford will conduct business in a manner that protects people, property and the environment.

We are committed to providing a safe and healthy workplace for all employees, complying with applicable

legislation wherever we work in the world, and protecting the environment and the quality of life in the

communities in which we work.

At Weatherford, we recognize risk is inherent in everything we do. We believe risks can be eliminated

or mitigated through the consistent application of sound management strategies.”

Weatherford’s Health, Safety and Environment Policy

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515 Post Oak Blvd.

Suite 600

Houston, Texas 77027 USA

Tel: 713.693.4000

www.weatherford.com

Weatherford products and services are subject to the Company’s standard terms and conditions, available on request orat www.weatherford.com. For more information contact an authorized Weatherford representative. Unless noted otherwise,

trademarks and service marks herein are the property of Weatherford. Specications are subject to change without notice.

Weatherford sells its products and services in accordance with the terms and conditions set forth in the applicable contractbetween Weatherford and the client.

© 2006 Weatherford. All rights reserved. Brochure 2828.00

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