10/25/2011
Packer Selection and Design
Prof. Sushanta Sarkar
PACKERS
A Packer is the part of the completion equipment which seals
the casing tubing annulus.
Packers are usuallyy run for the followingg reasons:
Provides an effective isolation of the casing tubing annulus from
the produced fluids for safety purposes, thus limiting well
control to the tubing at surface.
To isolate the casing from corrosive fluids and/or high pressure.
To stabilize and control flow from pay zones.
In conjunction
j
with an artificial lift system
y
((isolation and
control) , in gas lift, Jet Pumps.
To selectively produce multiple zones (isolation)
Selective stimulation becomes feasible.
Wire line and down hole operations become possible.
Hold a annular well killing fluid.
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PACKERS
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Materials Selection for Packers
STEEL SELECTION
All metal pparts heat- treated to a maximum hardness of 22 RC,
subjected to a tensile load conform to NACE standard MR-0175 for H2S service. Differential pressure should not exceed
10,000 psi.
Alloy steel heat- treated to a maximum hardness of 36 RC. For
pressure differentials not exceeding 15,000 psi.
410 stainless steel heat-treated to a maximum hardness of 22
RC .Conforms to NACE standard MR-01-75 for H2S or CO2
service. Differential pressure should not exceed 10,000 psi. Use
where corrosive environments will be encountered.
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Materials Selection for Packers
SEAL SELECTION
Standard seal stack
Standard Seal Sacks are made up of Nitrile chevron seals
and steel spacer rings. It is suitable for normal service and
not exceeding 325 degree F This type of seal stacks are
not recommended low temperature gas wells (less than
120 degree F) The seal stack should not be allowed to
leave seal bore in service.
Materials Selection for Packers
V-RYTE SEAL STACK
V-Rite-Seal Stacks are made up of Viton chevron seals
with Teflon and Ryton back-up rings, and Ryton front up
rings. This types of seal stacks are suitable for any well
fluids except amine based inhibitors. These seals have
been tested at 400 degree F , with 10,000 psi differential
y
conditions and 15,000 psi
p under static
under dynamic
conditions. Should not be allowed to leave seal bore in
service.
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Materials Selection for Packers
BONDED SEAL STACK
Two nitrile or viton seals are bonded to each metal
insert with a inner O-Ring and these inserts are
separated by spacer. This type of seal stacks are used
where seal movement out of the seal bore cannot be
prevented. Nitrile seal units are suitable for normal
p
of 350 degree
g
F.Viton
service and upp to a temperature
seal units are suitable for sour service ,in all well fluids
except amine based inhibitors, and up to a temperature of
250 degree F.
Materials Selection for Packers
K-RYTE SEAL STACK
A Baker Packer development consists of Kalrez chevron
seals, backed-up by Teflon and Ryton back-up rings, and
Ryton front-up rings. This type of seal stack resists the
effect of H2S, CO2, amine inhibitors and highly corrosive
treatment fluids. Baker has tested these seals at 450
g
F and 15,000 psi
p differential under static
degree
conditions and 500 degree F and 10,000 psi differential
under dynamic conditions, Seal movement should be kept
to a minimum and seal should never leave the seal bore.
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Hydraulic Packer & Dual Hydraulic Packer
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Polished Bore Receptacles
POLISHED BORE RECEPTACLE PACKERS (PBR)
To over come problems of packers sticking and to allow for a maximum packer
bore where the casingg diameter is limited (deep
( p high
g pressure
p
wells)) a new tool has
been developed: the polish bore receptacle packer, which consists of a flow tube
moving in a polish bore receptacle. The latter could be incorporated in the casing
string as a nipple or tied to a liner (type) top extension.
CASING SEAL RECEPTACLE
The Casing Seal Receptacle is a casing sub containing a seal bore and left-hand
squire thread both of which are compatible with standard Packers tubing seal
assemblies. It is run as an integral part of the casing string usually as a crossover
between casing sizes. hen cementing or doing remedial work inside the casing, a
sleeve is inserted in the Polish Bore Receptacle to protect the bore,
bore
The tubing string is run with standard tubing seal assembly attached with wire-line
accessories. The Shear-Out Anchor Tubing seal assembly is released by either tubing
rotation or sufficient pull to shear loose. If heavy mud is left in the annulus, a
Locator Seal Assembly may be required.
PBR and Seal Assembly
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RETRIEVABLE PACKER BORE RECEPTACLE.
The Retrievable Packer Bore Receptacle is design to be
anchored into the top of a retainer production packer or
a liner hanger by means of an anchor .The PBR seal
assembly can be shear-screwed in place in the PBR. The
PBR assembly with its anchor seal assembly can then be
latched into the hydraulic set retainer production packer
and entire completion string is run in and set on the
tubing string in one trip.
The anchor seal assembly can be latched in latched out or
latch in rotate out type. A retrieving tool is required to
retrieve the PBR after pulling out of the tubing strings
RETRIEVABLE PACKER BORE RECEPTACLE.
ADVANTAGES OF POLISH BORE RECEPTACLE PACKER SYSTEM.
PBR can be designed to provide maximum bore.
The completion string can be set in one trip and save considerable rig time.
Combination of packers and PBRs can be possible.
P li h d bore
Polished
b
and
d sealing
li elements
l
t allow
ll
movements
t off up to
t 40 feet.
f t
The seal resistance to two types of fluids (packer fluid and produced fluids) is overcome by using two types of
sealing materials
Floating device which effectively eases work-over problems
The liner hanger is protected from the pressure differentials induced from the top (in the case of upper zone
stimulation for instance).
LIMITATION OF POLISH BORE RECEPTACLE PACKERS SYSTEM
Permanent buckling may occur if motion induced by pressure forces is too great (large area subject to piston
effect)
Annulus pressure could be difficult to monitor as the fluid level is always changing (this can be overcome by
using an top packer).
Movable seals may have shorter life than permanent packer seals. ( the movements should be minimized to
reduce seal wear ).
If no movement occurs, seals may be vulcanize and stick in the polished bore receptacle, creating a problem.
This problem should be minimized by the choice of appropriate sealing material.
The option of a polished bore nipple receptacle integrated in the casing string is not recommended, as it could
be severely damaged by unavoidable drill pipe trip in the hole.
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MECHANICAL SET PACKER
Mechanical Packer is a single string retrievable casing packer. It
sets and retrieves mechanically. It is a service packer used in
Layer wise testing,
Squeeze cementing,
Stimulation,
To find injectivity,
To find casing leakage.
Types of mechanical set packer:
Weight set Mechanical Packer
Single-Grip Mechanical Packer.
Double-Grip Mechanical Packer.
Tension set mechanical Packer.
Mechanical Packer
Advantages of the Mechanical Packer
It is a very useful packer for well service/repairing job during work over operation.
Can be released and reset at another depth at will,
will if sealing elements stay intact.
intact
The packer can be reused in other applications.
The packer does not have to be milled out, if it becomes necessary to remove it,
thus saving rig time.
Limitations of the Mechanical Packer
Available only as single string packer.
Deviated well often limit the use of compression
compression-set
set packer
Hold-down buttons can be expected to fail, ( at O-ring seals) after numerous
reversal in pressure.
It can not stand for a higher differential pressure..
Cannot be used as a completion packer.
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Tension Packer and Mechanical Packer
Tension
Packer
Mechanical Set
Dual Grip Packer
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