EASYWELL Swellpacker™SystemDelivers · 3 Figure1—Swelltestingcharts. AsecondSwellpackersystemidenticaltothefirstbut designedtosetin12dayswasinstalledinthesecondwell...

Swellpacker™ System Delivers

Step Change in Zonal Isolation

for Intelligent Well Completions

RedTe ch™ PAPERPart of the RedTech Learning Series

Novembe r 2 0 0 7

HALLIBURTON

EASYWELL

An independent Operator offshore California successfully deployed oil-swelling elastomer

technology (Halliburton’s Swellpacker™ isolation system) during intelligent well completions,

accomplishing zonal isolation in three wells after conventional cementing and perforating

techniques failed. By successfully applying intelligent well completion and swelling packer

technologies together, the Operator lowered development costs and optimized production rates

while complying with the United States Minerals Management Service (MMS) that regulates all

offshore California drilling and completion operations in federal waters. The Operator was able to

further benefit from the combination of these advanced technologies as they deliver significantly

greater safety than conventional completion systems.

Business Challenge

A California independent Operator’s offshore field was too small to support a dedicated platform.

Thus, an extended-reach drilling campaign was initiated to produce the field from an existing

platform, drilling more than 16,000 ft through the highly fractured, highly faulted formation. A

predrilling study foresaw extensive production risk and uncertainties including vulnerability for

rapidly initiating water production. The intelligent well completions require the use of a large 7-in

liner for production (resulting here in a diminished area for annulus and cementing sheath).

Achieving zonal isolation is critical to minimize early water production in high-departure and

high-angle wells but conventional completion

techniques previously employed in neighboring

fields proved unsuccessful. A step change toward

achieving zonal isolation was needed.

Halliburton SolutionHalliburton addressed these challenges

successfully with Easywell Swellpacker technology

after the technical review and approval of the U.S.

MMS. Oil-swelling elastomer packers (Swellpacker

isolation system) can reliably deliver zonal

isolation even in openhole completions. An

intelligent openhole completion was chosen due

to the complexity of the reservoir characteristics

and the need to manage water production without

the need for well intervention.

EASYWELL

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Operator ResultsDiscovered in 1982 by Chevron, the Rocky Point field (6

miles northwest of Point Conception, California and now

under the ownership of an independent Operator) totals

8,585 acres and is smaller than the adjacent Point Arguello

field, making it difficult to support the expense to construct

and install a dedicated platform. Extended-reach technology

was therefore chosen to develop the field from the existing

Platform Hidalgo, drilling more than 16,000 ft through the

highly fractured, highly faulted and complex reservoir.

In May 2003, before the drilling project, a front-end

engineering and design study foresaw, on the basis of

available data, a high degree of risk and uncertainty in the

overall recovery rate attainable, pressure support available,

time to first water breakthrough, speed of water cut

development and total economic impact. The study’s

recommendations therefore focused on minimizing total

costs for the life of the well while maximizing early and

ultimate recovery and minimizing the potential for early

water breakthrough in this strong-water-drive reservoir.

Completions for the Rocky Point field were initially

expected to be performed similarly to those for the Point

Arguello field. For that reason, the original completion

design had been to cement a 5½-in liner in an 8½-in hole,

since several nearby operators had used this design.

However, a larger 7-in liner was specified to allow for the

intelligent completion valves. As a result, the Operator

ordered additional modeling and a fit-for-purpose cement

to accommodate the reduced area for annulus and cement

sheath imposed by the 7-in liner in the 8½-in hole. Fit-for-

purpose rig equipment included one 750-ton alternating-

current top drive, three 1,600-hp mud pumps, one 1,800-

bbl capacity drilling fluid system, one 500-kPa setback and a

racking capacity of 22,000 ft of 5½-in drillpipe.

The completion methods first considered for the Rocky

Point wells were (1) a conventional cemented and

perforated liner combined with swell packer technology or

(2) a slotted and predrilled liner. Historically, wells in the

region have been successfully completed using slotted liners,

however, this technique may not achieve zonal isolation

since slotted liner lengths can exceed 3,000 ft and cementing

to shut off water production is a debatable technique.

Therefore a conventional cemented and perforated liner was

initially selected for well completion, though without a

Swellpacker isolation system because of the Operator’s

limited experience with swelling elastomer technology.

All three extended-reach wells were conventionally

cemented to seal the annulus. The first cement job went as

designed. Drillpipe-conveyed perforating of more than

1,250 ft with five ½-in holes per foot was completed

without incident, resulting in a successful triple-zone

intelligent completion. The second well was also cemented,

however, a remedial squeeze was needed to provide zonal

isolation. Drillpipe-conveyed perforating of more than 870

ft with five ½-in holes per foot was then completed without

incident. The third well was cemented though a retainer had

to be set and squeeze cement proved necessary when

cement logs indicated poor cement bonding behind the 7-in

liner. Drillpipe-conveyed perforating of more than 565 ft

with five ½-in holes per foot was then completed without

incident.

Given the poor primary cementing history of the first three

wells, team members agreed to try running a 7-in predrilled

liner with Swellpacker isolation systems strategically placed

between the producing intervals.

In preparation, laboratory testing performed by Halliburton

verified packer swelling times and differential pressure

ratings. Figure 1 shows the results of the laboratory testing,

which allowed for a less complicated cementing operation

design using a 9-5/8-in swell packer to seal the 13-3/8-in by

9-5/8-in casing annulus, beginning with a field test in the

first well near 5,400 ft MD (3,500 ft TVD). Testing indicated

the Swellpacker isolation system would reach a 12.25-in ID

within 11–12 days with a tailored slow-set design.

Additional setting time (30 days total) was included in the

Swellpacker isolation system design to assure the Operator

of sufficient time for cementing the entire well. After 30

days, the casing annulus was tested to 1,500 psi for 30 min.

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Figure 1—Swell testing charts.A second Swellpacker system identical to the first but

designed to set in 12 days was installed in the second well

near 5,400 ft MD (3,500 ft TVD) and tested to 1,500 psi for

30 min. Two successful tests raised the Operator’s

confidence in the Swellpacker system and demonstrated

that a second production phase using a predrilled liner with

Swellpacker isolation systems for zonal isolation had merit.

Four zones were ultimately completed in each of the three

wells with the aid of three premium Swellpacker isolation

systems. Intelligent well completions were successfully

installed in severe reservoir conditions with highly acidic

concentrations of hydrogen sulfide.

In summary, the Operator found problems with zonal

isolation during conventional cementing operations in

three wells. Swellpacker technology was tested and deployed

with the production string enabling successful zonal

isolation of the 95/8-in casing as well as the 7-in

production liner. Swellpacker technology has demonstrated

its usefulness to simplify the well completion process and to

reduce development costs.

Operator BenefitsA key benefit of Swellpacker technology is its ease of

deployment. With no moving parts, downhole activation or

surface equipment required, the Swellpacker isolation

system acts simply as part of the completion or casing

string and can be deployed in a single trip. In addition,

Swellpacker systems don’t require service technicians.

By deploying the Swellpacker isolation system during

intelligent well completions, the Operator accomplished

zonal isolation in three wells after conventional cementing

and perforating techniques were unsatisfactory. In addition,

the Operator lowered development costs and optimized

production rates. Furthermore, these advanced completion

technologies used in combination offer greater reliability

and safety than conventional completion systems because

downhole flow control valves and monitoring equipment

minimize platform personnel’s exposure to high-pressure

wellhead components when making adjustments for well

optimization.

Intelligent well completion deployment

Figure 1

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The joint use of Swellpacker technology and intelligent well

completion technologies delivered the following direct

benefits for the Operator:

Zonal isolation. Zonal isolation was successfully achieved,

minimizing early water production after deploying

Swellpacker isolation systems that had been proven to

sustain 1,500 psi in differential pressure for 30 min.

Flow control. A total of 18 retrievable flow control valves

and 18 permanent downhole quartz gauge systems were

installed, with no failures. As a result, each successfully

isolated zone received a dedicated valve and permanent

gauge that read annular conditions in the reservoir.

Intelligent well technology thereby enabled a reduction in

intervention and delivered the full promise of reservoir and

production management, monitoring and control, remotely

and in real time.

• The use of intelligent valves has allowed dry oil

production from the upper and middle interval and water

shutoff from the lowermost interval. Shutting in the lower

valve resulted in immediate, uncharacteristic and

permanent water shutoff.

• Swellpacker isolation systems helped deliver additional

production by completing three zones with intelligent

completion equipment as opposed to the original plan of

four mixed zones using conventional completions.

• The use of remotely operated downhole valves has

enhanced safety by eliminating hazards typically

associated with conventional well intervention operations.

• Downhole information received during well stimulation

treatments enabled the Operator to gain, for the first

time, a close understanding of the effects of stimulation to

each producing zone in real time. This understanding has

made changes in stimulation procedures as well as

sandface completions possible.

Efficiency. This advanced completion lowered development

costs and optimized production rates from hydrocarbon

reserves.

• Problems with isolation of traditional cementation

operations are typical in similar well sections. Swellpacker

technology nevertheless proved itself to be a reliable

solution.

• Intelligent completions techniques are not only justified

by the strict drilling regulations for offshore California

but they yield more efficient reservoir drainage and

reduce intervention costs owing to undesirable water

production.

• Savings of about 36% can be realized with the use of

Swellpacker technology and predrilled liners compared to

conventional cemented and perforated liners. The savings

are even greater if remedial squeeze operations are

considered.

• Intelligent well completions can reduce water production

as well as control the reservoir remotely.

In summary, these three wells are considered a technological

success, proving that the use of Swellpacker technology

together with intelligent well completion design is a reliable

and economical solution for zonal isolation, downhole

monitoring and flow control.

Swellpacker TechnologyThe Swellpacker isolation system employs standard oilfield

tubulars with a rubber layer chemically bonded along the

length of the packer element. The rubber element swells

upon exposure to hydrocarbons to form an effective annular

seal 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 absorption process.

The wellbore fluid’s viscosity and temperature are key

variables in determining the time required for the swell

packer to absorb hydrocarbon and ultimately to set.

Swelling of the packer is consistent along its length.

Although hydrocarbons will not degrade the rubber, they

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 [email protected]

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.

Thousands of Swellpacker systems have been run in

numerous wells worldwide for a variety of applications,

including zonal isolation across the reservoir as a substitute

for cement and providing backup should the liner

cementation prove unsuccessful.

This Halliburton white paper is a summary of IADC/SPE

105443 “Are Swelling Elastomer Technology, Preperforated

Liner, and Intelligent Well Technology Suitable Alternatives

to Conventional Completion Architecture?” by Gary P.

Hertfelder and Kurt Koerner, Plains Exploration and

Production Company; Allen Wilkins, Easywell; and Lilian

Izquierdo, Schlumberger, paper presented at the 2007

IADC/SPE Drilling Conference, Amsterdam, The

Netherlands, 20–22 February.