W H I T E PA P E R A u g u s t 2 0 0 6

Swell Technology: Primary

Cementing’s New Companion

CEMENT ING

CEMENTING

Business ChallengeAs our industry continues to strive for greater success in achieving zonal isolation, success

may be defined by current performance, longevity, and added value. Drilling departments

might weigh success factors differently than production departments ten years later. This

system addresses both considerations.

Over the years, service companies have introduced a variety of cementing materials and

processes designed to increase both current performance and long term zonal isolation

while attempting to balance the cost benefit ratio of the two. One of the more recent

introductions appeared in 2002 when Swellpacker™ isolation systems were introduced to

the marketplace.

To date, over 2000 forms of swell technology have been installed with the majority being

deployed in conjunction with completion activities such as packers run on tubulars. Only

recently (2005) have Swellpacker systems

started to appear as an integral part of

zonal isolation activities.

The key factors for successful cementing

operations are well known (see Cementing

Best Practices) and are usually considered

in the design stage. However, there are

times when well conditions do not allow

the use of many best practices. For

instance, many cases can be found where

an optimum theoretical centralization

design was modified due to torque and

drag considerations. Also, circulation

rates may be reduced over concerns

of breaking down a formation. Having

Swellpacker systems available often can

mitigate the effects operational expedience.

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How They Function:

Swelling elements are made from materials such as styrene-

butadiene or other types of rubber that at the molecular

level form tight helix coils. Through a process known as

thermo-dynamic absorption, hydrocarbon

molecules are absorbed into the material to satisfy open

sites on the helix. The larger hydrocarbon molecules cause

the helix to open or expand. Expansion time can be varied

by slowing down or speeding up the absorption rate.

Cementing Best Practices

1. Flow rate—target turbulent flow

2. Pipe centralization (70% standoff)

3. Optimum hole size

4. Circulation to condition mud

5. Address gas flow issues

6. Good mud properties (PV>10; YP>5)

7. Optimum mud gel strength

8. Good mud fluid loss properties (API=7)

9. Top & bottom cementing plugs are used

10. Pipe movement (reciprocation & rotation)

11. Use spacer volume for 10 min contact time

12. Place weighted viscous pill in rat hole

13. Minimum shoe track length of 1 casing joint

Advantages and Applications

Swellpacker systems have many advantages that can

compliment the cementing operation. These include:

• Operational simplicity

• Design simplicity

• Robust design

• Self healing

• Time delay to first sealing

• Future swelling

• Autonomous functionality

• No operational processes

• Functions in gauge or irregular profiles

• Specialist not required to install

• Low running friction

“SwellPacker™ Systems have many

advantages that can compliment

the cementing operation.“

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Applications

Swellpacker systems have the proven capability to address

the following issues that may arise during cementing

operations and any time thereafter:

Case Histories

Case 1: North Sea

This North Sea well was being drilled to evaluate a HPHT

reservoir at 4300 m (14,000 ft) TVD and 7300 m (24,000 ft)

MD. The cementing of 13 3/8-in. casing in the 17 1/2-in.

hole section was originally designed to bring cement back to

surface, however, the following obstacles were uncovered:

• Full cement job required 15% more cement than rig

could store

• Off-loading cement during the job was problematic

• Temperature differential between shoe and TOC was 90°F

• Strength development of lead cement would be hindered

• High deviation could hinder solids removal

• High deviation could hinder mud conditioning

• Casing could be on low side due to high deviation

• Unable to reciprocate or rotate casing

• Gas flow potential required specialized slurry

• Lost-circulation zones could interfere with cementing job

Solution:

Combine standard cementing practices with a Swellpacker in

a complimentary fashion to achieve complete zonal isolation.

Cement was used to tack the bottom 800 m (2,600 ft) of

the 13 3/8-in. casing for wellbore stability concerns and a

Swellpacker was used in the open hole just below the

previous shoe joint at 2100 m (6,900 ft) to seal the annulus.

The packer was designed to completely fill the annular

space and withstand 5,000-psi differential pressure. The

packer element was designed to have a 14-day delay before

establishing a seal. This would allow a complete recovery

Micro-annulus

Mud channel

Casing

Cement

CementAssurance™ Tool

Cement Assurance™ Toolcompletely fills available spaceincluding irregularities

The Cement Assurance™tool fills micro-annulus,mud channels, and voids

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of the casing string if needed. The oil-based drilling mud

in the annulus provided the catalyst for the activation of

the Swellpacker system.

The operations were performed as planned and the

annulus remains sealed.

Case 2: Mid-East

This Middle Eastern horizontal level 2 MLT high-rate

gas well presented a unique challenge for creating zonal

isolation. The 9 5/8-in. casing would be run through a

window to over 9,000 ft with 6800 ft in the 12 1/4 -in.

open hole. Most of the open hole section was horizontal.

An effective pressure seal between legs of the multi-lateral

was required. Planning of the cementing operation

identified the following concerns:

• Less than optimal centralization

• High deviation could hinder solids removal

• High deviation could hinder mud conditioning

• Casing could be on low side due to high deviation

• Unable to reciprocate or rotate casing

• Gas flow potential required specialized slurry

Solution:

For this demanding application, a Cement Assurance™

tool was used as a companion technology to assist the

cementing system. Two packers were run on the casing

and spaced out such that they were just below each MLT

junction. The packers helped eliminate potential annular

gas flow due to mud channeling or a micro-annulus caused

by cement debonding from the casing.

The casing running operation was performed as normal.

The cementing operation was performed as normal. The

well remains casing pressure-free.

Installation

Halliburton provides two options for installation of

the Swellpacker system.

Slip-on Swellpacker

System

Option 1: Site Installed

A slip-on version of the

Swellpacker system is

available to facilitate

installation in the field.

The Swellpacker system

assembly is composed

of two end rings and an

element section that are slipped over a length of casing. The

end rings attach to the casing with set screws and hold the

element in place. Given the swelling nature of the element,

it will seal itself to the casing when downhole swelling takes

place. The standard slip-on product typically can be installed

in less than 15 minutes by the rig crew or casing crew.

Hostile environment Swellpacker System

Option 2: Factory Installed

Halliburton's hostile environment Swellpacker system

is assembled at our manufacturing facility. Whether it is

on customer-provided tubulars or on our own, this packer

is designed to address difficult well conditions like long

horizontal open hole sections, multiple trips through

windows, higher temperatures, and short-radius bends.

This assembly utilizes mechanically fastened end-rings

and vulcanization of the element in place.

Sales of Halliburton products and services will be in accord solelywith the terms and conditions contained in the contract betweenHalliburton and the customer that is applicable to the sale.

H05112 08/06© 2006 Halliburton. All Rights Reserved.

HALLIBURTONwww.halliburton.com

The Complete Approach

Operators can now address Sustained Casing Pressure

with a three phase approach to solving this dilemma.

1. WellLife® cementing service improves the mechanical

properties of the cement sheath.

2. The Cement Assurance tool addresses micro-annulus

that can form when the cement sheath debonds from

the casing and mud channeling associated with poor

pipe centralization.

3. The Swellpacker isolation system provides a complete

annular seal to prevent gas from reaching the surface.