Soluções de Tubulação Expansível

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Expandable-Tubular Solutions
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Expandable-Tubular Solutions
A method has been developed to
expand the diameter of solid tubulars
downhole. This technology provides
cost-effective solutions to several
tubular problems that have presented
obstacles to comprehensive reservoir
exploitation. Operators can use
smaller holes to drill deeper vertical
wells or to extend the reach of deviat-
ed wells to access untapped reser-
voirs. In older fields, existing well-
bores can be repaired with expanded
tubulars or their tubular strength and
integrity can be increased.
Introduction
Expandable-tubular technology is, in
its simplest form, cold working steel
downhole. A mandrel or pig is used to
mechanically deform the pipe perma-
nently. The pig is propelled by pres-
sure drop across the pig or by a direct
force. Expansions greater than 25% of
pipe diameter can be accomplished,
but most applications require less
than 25% expansion.
Multiple applications exist for this
technology, but three initial applica-
tions have been identified. An expand-
able-openhole-drilling-liner system is
used to solve lost-circulation problems
and to seal off trouble zones, such as
shallow water flows and subsalt rubble
zones. The expandable cased-hole
liner system is used to repair long cor-
roded casing intervals or to seal off
perforations. The expandable liner-
hanger system currently under devel-
opment uses expandable tubulars to
create a leakfree liner hanger.
Expandable-Tubular Technology
Solutions offered by expandable-tubu-
lar technology are based on analytical
modeling, laboratory tests, and large-
scale field tests with modified flush
connections and new mandrel (pig)
designs. Extensive numerical model-
ing has been performed by use of
commercial finite-element codes.
System Testing. All final designs were
tested in a three-part series of expan-
sion tests. Samples from each expan-
sion test were subjected to a series of
mechanical tests.
Laboratory Tests. Laboratory test-
ing consisted of mechanically pressing
the mandrel or pig into each tubular
with a hydraulic press. Solid tubulars
that are regularly expanded are tested
for both mechanical and hydraulic-
pressure integrity. Other tests deter-
mine sulfide stress cracking and
hoop-stress resilience.
Surface Expansion. After satisfacto-
ry laboratory testing, large-scale sur-
face expansions are performed.
Hydraulic-pump pressure is used to
propel the expansion mandrel
through the tubular. Expansion is
accomplished by the mechanical force
the mandrel exerts on the tubular
when the hydraulic pressure is
applied. Pressure required to initiate
expansion ranges from approximately
1,900 psi for 133/8-in. casing to
5,700 psi for 31/2-in. coiled tubing.
Test-Well Environment. Once suffi-
cient data have been collected from
surface expansions, the expandable
system is tested in a test-well environ-
ment. After the entire system is fully
expanded, the entire expanded instal-
lation is retrieved from the test well,
dissected, and final tests are per-
formed to ensure field performance.
Mechanical Properties. Knowledge
of post-expansion mechanical proper-
ties is imperative for accurate service
rating. Post-expansion strength, duc-
tility, impact toughness, collapse, and
burst have been studied for selected
pipe sizes and compared with those of
nonexpanded pipe. Table 2 in the full-
length paper summarizes results of
mechanical-property tests for 51/2-in.,
17-lbm/ft L-80 casing. The table
shows that the expansion process
does affect mechanical properties of
the material. Ultimate tensile
strength tends to increase and elon-
gation tends to decrease after expan-
sion. Though hardness and tensile
properties of the L-80 casing tested
were altered by expansion, the casing
still met American Petroleum Inst.
requirements. Similar results were
obtained with grade K-55 casing.
Expansion decreases collapse rating
of tubular goods, probably the result
of the Bauschinger effect. The
Bauschinger phenomenon occurs
when plastic flow in one direction
(expansion) lowers the applied stress
at which plastic flow begins in the
reverse direction (collapse). Test data
for the L-80 casing indicate that col-
lapse resistance should decrease by
approximately 30% as a result of the
expansion process. Studies have
shown that a significant portion of ini-
tial collapse resistance of the material
can be recovered through a special
process currently under development.
The expansion process appears to
have no detrimental effects on burst
strength. Expanded L-80 casing burst
pressure meets or exceeds general-for-
mula expectations, and the fracture
surface of all samples tested has
shown ductile fracture behavior. 
Technology Applications
Expandable Openhole Drilling Liner.
The expandable-openhole-drilling-
liner system provides effective, cost-
saving solutions for many openhole
operations. Increased casing length
with negligible reduction in diameter
can be useful in operations where very
large casing programs in the upper
hole section are cost prohibitive. This
system allows operators to extend
conventional casing programs in
exploratory wells to reach promising
zones that are deeper than expected.
Once expanded inside existing casing,
the expandable tubulars allow the
operator to drill to deeper zones.
Liner diameter at total depth is larger
than normally possible with a conven-
tional casing program and allows con-
This article is a synopsis of paper SPE
56500, “Expandable-Tubular Solutions,”
by Andrei Filippov and Robert
Mack, Shell; Lance Cook, Patrick
York, SPE, and Lev Ring, SPE,
Enventure Global Technology; and Terry
McCoy, Halliburton Energy Services,
originally presented at the 1999 SPE
Annual Technical Conference and
Exhibition, New Orleans, 3–6 October.
MAY 2000
 
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MAY 2000
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48
version of an exploratory well to a
production well.
The expandable-openhole-drilling-
liner system can be used in lost-cir-
culation or shallow water-flow zones
in deepwater and subsalt environ-
ments. In older fields un-
dergoing redevelopment,
the expandable openhole
drilling liner can aid in
reaching deeper reserves
and can isolate water zones
that have penetrated hori-
zontal re-entry wells.
Running Sequence. Once
the hole section is drilled,
the expandable drilling
liner is run into the hole
and set in the slips. One or
two elastomer-coated pipe
joints that will serve as the
liner hanger and liner-top
seal are made up to the top
of the expandable openhole
drilling liner. The pig
launcher is located at the
bottom of the system.
Because the pig launcher
has a thinner wall than the
expandable tubular, it can
be tripped into the hole
through the previous cas-
ing string. The drillstring or
work string is run and latches on top
of the pig. After the string is run, an
inner-string cement job is performed
with a special cement slurry. A latch-
ing dart that seals off the float equip-
ment and creates a pressure chamber
follows the tail end of the cement job.
The surface pumping unit increases
hydraulic pressure through the work
string and pig into the pressure-cham-
ber area. When the pressure inside the
pressure chamber exceeds the pressure
required to develop sufficient mechan-
ical force across the pig/expandable-
casing interface, the casing begins to
extrude over the pig. The work string
and pig are pumped out of the hole as
the pipe is extruded over the pig.
When the expansion process enters
the previous casing string, the elas-
tomer clads the two pipes together.
The elastomer closes the voids caused
by ovality problems or drilling wear
and improves mechanical and
hydraulic integrity. This seal typically
forms a mechanical connection with a
225,000-lbf/ft pullout strength. 
Expandable Cased-Hole Liner. The
expandable-cased-hole-liner system
is used to repair existing damaged or
worn casing. The system makes it
possible to upgrade exploration-
grade casing toa sturdier production
casing with minimal casing-inner-
diameter (ID) reduction or seal off
perforations for recompletion or
deeper drilling.
Running Sequence. The running
sequence for expandable-cased-hole-
liner systems is similar to the running
sequence for the expandable-open-
hole-liner system. First, the wellbore
that is to be lined is cleaned and its
condition and ID are evaluated. This
system also is expanded from the
bottom up. Fig. 1 shows the expand-
able-cased-hole-liner-system running
sequence. An elastomer coating cov-
ers the entire interval being lined to
enhance the hydraulic integrity of the
liner. This elastomer fills the voids
between the perfectly circular expand-
ed pipe and the existing pipe, which
usually is not perfectly circular.
Mechanical pullout strength is
reduced from 225,000 lbf/ft with
the elastomer to approximately
13,000 lbf/ft without it.
Expandable Liner Hanger. The
expandable-liner-hanger system pro-
vides a simpler, cost-effective alternative
to conventional liner hangers and liner-
top packers. This system combines the
functional requirements of a liner hang-
er and liner-top seal while minimizing
the need for liner-top squeezes.
Systems Description
Expandable-tubular technology must
be considered as a total system. Some
expandable-tubular-sys-
tem components are the
mandrel or pig assembly,
shoe joint, expandable
tubulars, expandable
connections, expandable
components of the work
string, and elastomer.
Also included in these
systems are the pig-lubri-
cation system, zonal-iso-
lation system, and equip-
ment to evaluate the
expanded-casing integri-
ty. Each expandable
product has been devel-
oped as a system rather
than an individual com-
ponent such as a piece of
casing that can be
expanded or a mandrel
that can increase pipe
diameter. Each system
includes the required
application-specific hard-
ware, accessories, ser-
vices necessary to install
the hardware, and an expert team.
Specifications. Expandable-product
sizes range from 31/2×5-in. [meaning
that a 31/2-in.-outer diameter (OD)
tubular is expanded and sealed
inside a 5-in.-OD tubular] to a
133/8×16-in. system. The greatest
length expanded downhole has been
1,000 ft, but tests indicate that 2,000-
to 5,000-ft expansion lengths should
be possible.
Conclusions
1. Expandable openhole drilling lin-
ers can reduce costs and allow access
to reservoirs that previously could not
be reached economically.
2. Expandable cased-hole liners can
maintain profitable production from
older fields by remediating wells with-
out using new production liners that
significantly reduce cross-sectional
flow areas and production.
Please read the full-length paper for
additional detail, illustrations, and ref-
erences. The paper from which the
synopsis has been taken has not been
peer reviewed.
JPTJPT
Fig. 1—Expandable-cased-hole-liner-system running
sequence.