Swellpacker™ Technology

Enables Intelligent Completions

for Enhanced Oil Recovery in

Openhole and Multilateral Wells

Novembe r 2 0 0 7

HALLIBURTON

EASYWELL

RedTe ch™ PAPERPart of the RedTech Learning Series

Multilateral and intelligent wells are evolving as key completion technologies to enhance and to

maximize hydrocarbon recovery. Such technologies require zonal isolation. Conventional

cementing techniques employ complex mechanical systems and packers to achieve isolation while

at the same time permitting potential failure points in the well design. A major Operator in the

Middle East capitalized on a successful multilateral and intelligent-well completion campaign by

partnering with Halliburton to implement an innovative and successful openhole completion

process for lateral isolation using the Swellpacker™ cable system.

Industry Challenge

Until recently, conventional completion techniques have employed cementing the mainbore

and/or using mechanical equipment such as packers to achieve zonal isolation. However, these

approaches involve complex operations and reduce the inner diameter (ID) of the casing string.

Furthermore, feed-through of hydraulic, electrical, or fiber-optic cable requires splicing the cable

lines, introducing a potential failure point in the well design. An innovative approach to intelligent

well completion for spliceless zonal isolation that simplifies openhole completions and addresses

the root causes of failure is an alternative that also reduces rig time, enhances production and

increases reliability.

Halliburton Solution

The Swellpacker cable system deploys a swelling

elastomer bonded onto a base pipe. The packer

element is manufactured with a channel to match

the cable size to be run. During operations, a

feed-through system opens the rubber elastomer,

allowing the control lines to lay down in the

channel without requiring a connection or a splice

of the cable at the packer. Once in the hole, the

elastomer swells in the presence of hydrocarbon,

remediating the splice in the elastomer while

providing an effective downhole seal between the

base pipe and the irregularities of an open hole to

maintain zonal isolation in even the most complex

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environments. Line installation, requiring up to 8-12 hours

per packer with conventional packers, is reduced to 10

minutes per packer with the Swellpacker cable system.

Furthermore, no moving parts or service technicians are

involved and any number of Swellpacker cable systems can

be integrated into the completion string and run in a single

trip.

Operator Results

A major Middle East Operator had successfully employed

horizontal and multilateral wells with greater than 8 km of

reservoir contact to maximize hydrocarbon recovery from

its reservoirs. In recent years, completion designs included

the integration of both intelligent and passive inflow control

completion systems, further enhancing the value of

maximum reservoir contact (MRC) wells by providing

inflow control, downhole monitoring capabilities and more

detailed inflow profiles.

The Operator’s first intelligent well completions were drilled

as 7-in fullbore wells using standard 3½-in internal control

valves (ICVs) and mechanical packers. This completion

approach proved to be very successful and is utilized in

numerous fields as required. With the goal of saving costs

associated with casing, the Operator partnered with

Halliburton and WellDynamics to develop a successful

openhole version of this completion process using

Swellpacker cable systems for lateral isolation while enabling

an efficient and more reliable deployment of the

communication lines of an intelligent completion by

eliminating the requirement for cable splices, control line

cuts and cable stripping.

Laboratory testing. Before installing the first openhole

intelligent well completion using the Swellpacker cable

system, an extensive battery of laboratory tests were

performed with crude oil samples in a range of viscosities

from different oil fields to verify the Swellpacker cable

system’s swelling and sealing ability. Testing was carried out

at a major Gulf R&D center. The three main objectives of

testing were to verify the Swellpacker system performance

with respect to:

• Swelling capacity in a variety of crude oils

• Sealing capacity (ability to withstand differential

pressure) after swelling

• Expansion rate (time to complete seal and hold

differential pressure).

Scaled versions of the Swellpacker system (using a scale of

1:5) were employed to simplify handling in the laboratory.

Both separator crude oils and bottomhole samples were

studied. Reservoir pressure and temperature were applied to

the test autoclave during the swelling period to simulate

downhole conditions. Pressure was increased at

predetermined intervals of 50 psi until leakage occurred.

Conducting a number of differential pressure tests in a

given interval made it possible to determine the swelling

time for different hole dimensions and crude oils. Viscosity

is one of the major factors influencing the swelling process.

Results from the 1:5 scaled tests appear in Fig. 1, which also

details swelling profiles against time for Swellpacker system

sizes of the following dimensions:

• 3.5-in basepipe, 5.8-in OD Swellpacker system for

6-1/8-in hole ID

• 4.5-in basepipe, 5.8-in OD Swellpacker system for

6-1/8-in hole ID

• 7-in basepipe, 8.2-in OD Swellpacker system for

8.5-in hole ID.

In conclusion, laboratory testing verified (1) swelling and

sealing for a range of crude oil samples, (2) maximum

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differential pressure exceeding the required differential

pressure and (3) expected sealing time. These positive

results confirmed that the Swellpacker cable system could

provide the annular seal required for the planned openhole

intelligent well completions.

Intelligent well completions. The Operator’s intelligent

well completion design consisted of four subassemblies:

1. Swellpacker system and ICV for the mainbore

2. Swellpacker system and ICV for Lateral 1

3. Swellpacker system and ICV for Lateral 2

4. Pressure/temperature sensor and production packerin the 7-in liner.

The installation of the intelligent well completion assembly

gave the Operator a three-zone intelligent well completion

with each valve controlling inflow from each of the three

sections.

The original well was drilled conventionally, and the

laterals were then added which resulted in placing the

completion off-bottom. It is believed that the completion

fell into the first low-side lateral, thereby setting the

uppermost Swellpacker systems in the 7-in liner. As a

result, the uppermost ICV was not used. The second ICV

controlled the two bottom laterals and the mainbore in

commingled flow, while the third ICV controlled the first

low-side lateral.

A review of the production and pressure data from this

well indicated the Swellpacker cable systems provided

lateral isolation. Furthermore, test results indicated that,

when all laterals are open to production, total flow rate was

7.6 MBOD.When only the second ICV was open, the

mainbore and Lateral 2 contributed a total rate of 7.4

MBOD. The similarity in flow rates arises because the

Final Installation Schematic

Saudi Aramco Intelligent Completion

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mainbore and Lateral 2 are in a rock facies with better

permeability when compared to Lateral 1; therefore the

mainbore and Lateral 2 dominate the flow when all the

three laterals are open to production.

Test data also indicated that when Lateral 1 is opened to

flow while the second ICV is closed, production from

Lateral 1 is 5 MBOD, suggesting that Lateral 1 has the

potential to produce when the other two laterals are closed.

Testing was conducted when all downhole chokes were fully

opened and the surface choke was set at 25% open.

Currently, the well is producing at a rate of 6 MBOD with

1% water cut at an average pressure drawdown of 60 psi,

compared to a pre-workover rate of 1 MBOD and 15%

water cut.

A second well was drilled and completed using the same

Swellpacker cable systems and openhole ICV concept. This

time the completion was run in a dual lateral to avoid the

problem of running the liner into the lower lateral drilled

on the low side. This completion ran as planned and is

being evaluated.

Operator Benefits

The Swellpacker cable system offers multiple advantages

over conventional completion techniques. It has a

straightforward design and is able to reliably conform to

irregular wellbores. It can be tailored to swelling size and

time requirements. It can serve in openhole completions,

eliminating the need for a completion liner to achieve zonal

isolation and saving rig time and cost. The 7-in liner can be

replaced by a 6-1/8-in openhole section while still allowing

the Operator to install 3½-in ICVs; this slimming of the

wellbore continues all the way to surface, delivering

significant savings in time and cost. Lastly, a feed-through

system allows control lines and fiber-optic cables to be run

through without requiring a connection or a splice at the

packer.

Ultimately and economically, openhole intelligent well

completions using the Swellpacker system enable the inflow

from different reservoir sections to be remotely monitored

and controlled from the surface without well intervention.

Following the success of these first two intelligent well

completions, the Operator has selected Swellpacker

technology to deliver openhole annular isolation in its ICD

(passive ICV) completions for long horizontal completions.

The Swellpacker system makes it possible to place additional

annular barriers (one every 100 ft of horizontal section) and

to provide better compartmentalization and therefore better

inflow conformance, resulting in increased well recoveries

and delayed water breakthrough.

Future trilateral wells will be planned as new wells where

this new-generation openhole intelligent well design can

provide further opportunities to optimize well costs without

sacrificing inflow control.

Swellpacker Technology

The Swellpacker cable system is an annular isolation cable

feed-through packer for both open hole and cased hole

completions. This technology employs standard oilfield

tubulars with rubber layers chemically bonded along their

length. The rubber element swells upon exposure to

hydrocarbons to form an effective annular seal and a seal

around the control lines through a process known as

diffusion, which occurs as hydrocarbon molecules are

absorbed by the rubber molecules and cause them to

stretch. The oil enters the rubber, which swells the packer

and ensures that it will remain swollen, unlike water

swelling systems which can shrink due to the effect of the

osmosis process being reversible. Mere trace amounts of

hydrocarbons are sufficient to initiate the thermodynamic

absorption process.

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.

Biblio # 11/07© 2007 Halliburton. All Rights Reserved.

HALLIBURTONwww.halliburton.com/easywell

or email us at easywell@halliburton.com

The wellbore fluid’s viscosity and temperature are key

variables in determining the time required for the

Swellpacker system to absorb hydrocarbon and ultimately to

set. Swelling of the packer is consistent along its length.

Although hydrocarbons will not degrade the rubber, they

will alter its mechanical properties, such as hardness and

tensile strength, depending on the rubber’s volume increase.

Swellpacker elements are chemically bonded to a tubing or

casing joint with element lengths tailored to accommodate

the desired differential pressure. Slip-on sleeve designs are

also available, normally in 12-in and 3-ft lengths, but for

low-pressure applications.

The Swellpacker system is suitable to run “as is” in a water-

environment well that will ultimately produce oil and set the

packer. However, packer construction for an oil-based mud

system normally uses a multilayered design that delays the

onset of swelling while the packer is deployed into the well.

This Halliburton white paper is a summary of IADC/SPE

100824 “Swell Packers: Enabling Openhole Intelligent and

Multilateral Well Completions for Enhanced Oil Recovery”

by Drew Hembling, Salam Salamy and Abdullah Qatani,

Saudi Aramco; Neale Carter, Easywell (now with Sensornet

Ltd.); and Suresh Jacob, WellDynamics, paper presented at

the 2006 IADC/SPE Asia Pacific Drilling Technology

Conference and Exhibition, Bangkok, Thailand, 13–15

November.

Table 2 Pressure Text Results

Table 3 Swelling Profile vs Time