Subsea Chokes Brochure
User Manual: Subsea Chokes Resource Library
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Subsea Chokes
Setting the industry standard,
decade after decade
2
Early WILLIS* subsea choke
The World’s Most Advanced Subsea Chokes
Cameron provides surface and subsea choke and actuation solutions, project
management, system engineering, operability and training.
Cameron WILLIS* subsea chokes are designed for
use in production, water injection, gas injection,
gas lift and reverse flow applications with chokes
ranging from 2 in through 8in nominal sizes and
Cv from less than 1 upto 1,000.
Subsea chokes are typically used to:
■ Start up and shut in subsea wells
■ Balance pressures from different wells to a
common manifold
■ Reduce flowline pressures and costs
■ Protect against reservoir collapse
during startup
■ Control flowrates to minimize sand and water
production extending production life
■ Protect subsea gate valves from high-pressure
drops during startup and shutdown
Cameron offers both non-retrievable and insert-retrievable chokes. Non-retrievable chokes remain
permanently attached to subsea structures, while insert-retrievable chokes are designed so that the
trim, actuator and retention mechanism can be retrieved to the surface.
Cameron subsea choke trim options are easily interchangeable to accommodate changing
field parameters.
■ Plug & cage, external sleeve or multistage
■ Bi-directional flow, gas injection, gas lift, water injection (typically multistage) or water
alternating gas (WAG)
In 1975, Cameron manufactured the
world’s first subsea choke for the Mobil
West Delta project in the Gulf of Mexico
based on the design of manual surface
chokes and Multi-Orifice Valve (MOV*)
trim technology. The MOV controlled
flow via two rotating discs with
circular orifices.
Today, Cameron subsea chokes
have been used in more than 3,500
installations around the globe and feature
leading-edge technology:
■ Plug & cage, external sleeve and
multistage trim styles
■ High-pressure, high-temperature
designs of 15,000 psi, 400 degF
[204 degC], with 20,000 psi choke
under development
■ Insert-retrievable and fixed
non-retrievable designs
■ Hydraulic stepping and stand-alone DC
electric actuation
A History of Innovation
SpoolTree* system with insert-retrievable choke
Deepwater SpoolTree system with DLRT
insert-retrievable choke
3
With more than 30 years of experience
with high-pressure, high-temperature
(HPHT) technology for surface choke
applications to bank on, Cameron brings
proven performance to the subsea
domain with its evolutionary 15,000 psi
subsea chokes.
In fact, Cameron HPHT chokes have
already seen successful service in several
land and platform applications with
working pressures of 20,000 psi and
temperatures of 650 degF [343 degC].
As a result, our R&D team is developing
the world’s first 20,000 psi subsea
choke technology.
Subsea HP/HT chokes
API 6FA choke fire testing
Two Basic Designs Meet a Variety of Requirements
In shallow or deepwater, for subsea Christmas trees or manifolds, Cameron has the
subsea choke for the job. The non-retrievable choke is the ideal choice in subsea tree
designs with a retrievable flow control module or choke bridge. For other applications,
the insert-retrievable choke offers additional advantages.
Non-retrievable chokes
The first non-retrievable subsea choke was installed in 1975 and today, with almost 1,000 of these
rugged chokes installed, they are a proven, reliable choice.
Permanently mounted to a subsea structure such as a Christmas tree or manifold, the choke body may
also be incorporated into a retrievable flow control module or choke bridge, which can also house
flow meters and instrumentation. To maintain or replace the choke or trim, the flow control module or
choke bridge is retrieved. These chokes are usually fitted with a hydraulic stepping or stand-alone DC
electric actuator, but can also be adjusted by an ROV or diver.
Subsea Non-Retrievable Choke Summary
Choke Description Application Nom.
size†, in
MWP,
psi
Max Cv‡Flow curve
type
CC30FNR Non-retrievable choke Gas lift 3 5,000 13.6 P&C EQ%
38 P&C linear
CC30FNR Non-retrievable choke Production 3 10,000 86 P&C linear
64 P&C EQ%
CC40FNR Non-retrievable choke Production 4 5,000 256 P&C linear
206 P&C EQ%
CC40FNR 10k Non-retrievable choke Production 4 10,000 256 P&C linear
206 P&C EQ%
CC40FNR HP Non-retrievable choke Production 4 15,000 130 ES EQ%
CC40FNR Non-retrievable choke Water injection 4 5,000 76 MS33
345 P&C EQ%
CC50FNR 10k Non-retrievable choke Production 5 10,000 428 P&C linear
CC60FNR Non-retrievable choke Production 6 5,000 544 P&C EQ%
CC80FNR Non-retrievable choke Production 8 10,000 1,000 P&C linear
433 P&C EQ%
†
Nom. size refers to the seat nominal diameter, not the inlet or outlet end connection size. P&C—Plug & cage
EQ%—Equal percentage
ES—External sleeve
MS33—3 in, three-stage, multistage
‡ Reduced capacity and custom trims available.
CC40HP non-retrievable choke 15,000 psi MWP with
SLCA actuator
CC80 non-retrievable choke 10,000 psi MWP with SLCA
actuator Cv
=
1,000
4
Flow curves
Non-retrievable choke design highlights
■ Pressure ratings up to 15,000 psi
■ Temperature ranges from -50 to 400 degF
[-46to 204 degC]
■ Trim sizes from 2 through 8 in with
controllable Cv from less than 1 up to 1,000
■ 25-year design life, excluding wearing
trim elements
■ Meet or exceed API 6A /17D, ISO
10423/13628-4, NACE MR-01-75/ISO 15156
and NORSOK requirements
Insert-retrievable chokes
Cameron supplied the first insert-retrievable
choke in 1991. Since then, these highly
successful chokes have been installed on subsea
systems in varying water depths around the
world. A number of insert-retention designs
are available, including the totally vertically
retrievable lightweight compact choke, with
its dog-in-window connector, and the more
traditional three-segment clamp CLRT-style
choke with the latest edition to the family of
insert irretrievable chokes being the 8-in nominal
CC80SR insert retrievable large bore gas choke.
Insert-retrievable choke design highlights
■ Pressure ratings up to 15,000 psi
■ Temperature ranges from -50 to 350 degF
[-46to 177 degC]
■ Trim sizes from 2 through 8 in with Cv
upto 1,000
■ Designed for 25 years of service life,
excluding wearing trim elements
■ Meet or exceed all API6A/17D,
ISO10423/13628-4, NACE MR-01-75/
ISO15156 and NORSOK requirements
Subsea Insert-Retrievable Choke Summary
Choke Description Application Nom.
size†, in
MWP,
psi
Max Cv‡Flow curve
type
CC20SR Clamp insert choke Gas lift/MEG injection 2 10,000 6 PNT
CC20SR Clamp insert choke Gas lift 2 10,000 14 P&C EQ%
8P&C EQ%
CC30SR Clamp insert choke Gas lift/production 3 10,000 46 ES linear
33 P&C EQ%
CC40SR Clamp insert choke Production 4 10,000 288 P&C linear
210 P&C EQ%
CC40SR Clamp insert choke Production 4 15,000 200 P&C EQ%
CC40SR Clamp insert choke
Reverse flow water
injection (DBA multistage
anti-cavitation trim)
4 10,000
206 Single stage
130 Two stage
94 Three stage
CC30SRC Compact insert choke Gas lift 3 10,000 84 P&C linear
33 P&C EQ%
CC40SRC Compact insert choke Production 4 10,000 224 P&C EQ%
288 P&C linear
CC40SRC Compact insert choke Reverse flow water injection 4 10,000 216 MS32 EQ%
CC50SR Clamp insert choke Production 5 10,000 500 P&C linear
345 P&C EQ%
CC80SR CVC insert choke Gas production 8 7,500 1,000 P&C Linear
757 P&C EQ%
†
Nom. size refers to the seat nominal diameter, not the inlet or outlet
end connection size.
PNT—Profiled needle trim
P&C—Plug & cage
EQ%—Equal percentage
ES—External sleeve MS33—
3in, three-stage, multistage
‡ Reduced capacity and custom trims available.
Flow curve for CC50SR linear plug & cage Cv
=
500 Flow curve for CC80FNR linear plug & cage Cv
=
1,000
CC80SR 8-in nominal insert retrievable choke with CVC
collett connector
Cv
Stem travel, in
0 0.25 0.5 0.75 1.0 1.25 1.5 1.75 2.0 2.25
600
500
400
300
200
100
0
Cv
Stem travel, in
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
1,200
1,000
800
600
400
200
0
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Beginning with complete design services,
Cameron covers the realm of subsea
choke equipment and support to save you
time, money and headaches. Whatever
your requirements and however complex
the application, count on Cameron to
provide all the products you need to get
the job done:
■ Running tools
■ Intervention skids
■ Marine growth/debris caps
■ Guide funnels
■ Spare inserts
■ Commissioning seal kits
■ Trim change kits
■ Running tool spares kits
Complete choke resources
Choke insert ship and workover skid
CC40SRC compact choke
Dedicated compact choke running tool Dog-in-window connector
Exceptional Options Put You in Control
Insert-retrievable control chokes are available with a number of retention mechanisms,
including the lightweight vertically retrievable dog-in-window and the three-segment
clamp style.
With either design, the lockdown mechanism is released from the choke body so the
trim, actuator, seals and lockdown mechanism are retrieved to the surface as a self-
contained package for easy maintenance and trim replacement.
Compact insert-retrievable chokes
Our latest innovation to our revolutionary
compact choke is a dog-in-window connector
that offers tremendous advantages: It’s 35%
smaller, 45% lighter and 100% proven. It also
provides total vertical access—with absolutely
no compromise in performance.
Total vertical access is achieved via push/pull
rods, which engage/disengage dogs for insert
installation and retrieval, with the option of
hydraulic override for disconnect. And, because
it requires no horizontal access, the choke can
be more centrally placed, potentially reducing
the size and weight of the Christmas tree and
manifold significantly. Installation is simple
enough for smaller, more readily accessible
vessels to handle.
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Intervention tooling
Subsea manifold with compact chokes
CC40SR clamp choke with CLRT running tool funnel
CC40SR clamp choke with DLRT land out interfaceRetrievable subsea choke with clamp connector
The compact choke features an increased
trim cavity and annular area for reduced flow
velocity and a more uniform fluid presentation
to trim. Several cage-style trims are available,
including plug & cage for reverse and forward
flow and maximum Cv, and water injection
multi-stage, the choice for long-term operation
in cavitation-sensitive conditions and reverse
flow applications.
Our reliable Subsea Stepping Linear Choke
Actuator (SLCA*), comprehensively tested
and qualified to 10,000-foot water depths,
powers the new compact choke. The number of
actuation pulses can be halved on the open or
closed cycles independently, for either greater
control or faster operation.
Clamp-style insert-retrievable chokes
The simple clamp mechanism for latching the
insert to the choke body is a robust, ROV/diver-
friendly system. A remotely operated tool lowers
the insert with its clamp assembly into the choke
body. Guide pins align the insert, and hydraulic
and electrical connecters automatically mate
as the insert is soft landed. Finally, the ROV
operates a single threaded shaft to close the
clamp segments.
Cameron has developed configurations to allow
retrieval by the Cameron dedicated Clamp
Running Tool (CLRT) or a third-party Deepwater
Liftline Running Tool (DLRT) or Multi-Purpose
Running Tool (MPRT).
For deepwater subsea choke applications
requiring specialized intervention techniques,
Cameron supplies intervention tooling, test skids
and shipping skids designed and manufactured
to meet customer and project requirements.
In addition, Cameron insert-retrievable chokes
are compatible with the intervention tooling
currently supplied with the CAMTROL* subsea
production control system, which means the
same intervention tooling used to install and
retrieve subsea control modules can also be used
with Cameron chokes.
Deepwater liftline running tool
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Cameron subsea chokes feature a control
choke trim that uses hydrodynamic energy
dissipation to reduce erosion problems
and ensure positive flow. The flow enters
the inlet and circulates in the annulus
between the body and cage. The even
distribution of ports around the cage
determines maximum flow capacity.
High-velocity jets produced by the flow
collide in the cage center, dissipating
the most erosive energy away from the
downstream components.
Trim principle
The Cameron WILLIS* control choke cage-style trim design
incorporates “hydrodynamic energy dissipation” to reduce
erosion problems while ensuring positive flow.
High-performance actuators for every purpose
Cameron provides a variety of subsea choke actuators, including hydraulic “fail fixed”
actuators in operating pressures of 3,000 and 5,000 psi, which are compatible with water
or mineral-oil-based control fluids, as well as optional stand-alone DC electric actuators.
RD250 ROV gearbox
For use with Cameron non-retrievable chokes
with either diver or ROV operation, this actuator
is oil-filled and pressure-compensated, and has
an external marine-growth-resistant local-
position indicator, which allows the choke
setting to be easily read.
Subsea stepping linear choke
actuator (SLCA)
Developed for use on non-retrievable chokes
and now also used on the new compact choke,
the SLCA has two single-acting piston-pawl
assemblies — one for open and one for closed.
It is oil-filled and pressure-compensated with a
remote-position feedback via an LVDT, a marine-
growth-resistant local-position indicator and an
ROV override.
Aqua-Torq actuator
The Aqua-Torq* hydraulic stepping choke
actuator is designed to provide precise
incremental steps from open to closed. Oil-filled
and pressure-compensated, it incorporates a
marine-growth-resistant local-position indicator
and is available with an internal LVDT. The
actuator is fitted with flushing ports, and the
customer hydraulic interface is usually by the
weld tails on the stab mate hydraulic couplers.
Linear variable differential transformer
An accurate Linear Variable Differential
Transformer (LVDT) electronic remote-position
feedback sensor is available for both Aqua-Torq
and SLCA actuators. These non-contacting
position sensors are seal welded, digitally
calibrated and available in analog (4–20mA) and
digital (CANBus) output designs. Reliable, field-
proven and individually hyperbarically tested to
11,400-ft [3,475-m] water depths.
SLCA actuator
Aqua-Torq actuator
Digitally calibrateable LVDT
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Premier manufacturing
Control choke trim minimizes
erosion, maximizes control
Cameron subsea chokes are available in plug & cage
(forward and reverse flow), external sleeve and anti-
cavitation multi-stage trims.
Electrically Actuated Omni-Choke
The Cameron Omni-Choke* provides the
benefits and functionality of all-electric
actuation to both greenfield and brownfield
applications by virtually any traditional
multiplexed controls system through a simple
changeout of the choke. The SIIS compliant
interface allows the Omni-Choke to be treated
as a standard instrument, compatible with
traditional subsea control modules. Functioning
successfully since September 2008 in the K5F
Field in the North Sea, the Omni-Choke makes
all-electric performance a reality.
Cameron actuator performance
■ Operating depths to 10,000 ft [3,000 m]
■ Designed for 25 years of service life
■ Footprint identical to common
clamp-style chokes
In these cage-style trim designs, the production fluid is directed through the cage port so that it
impinges upon itself. The energy of the fluid is dissipated within the tungsten carbide trim, reducing
the wear on the choke and downstream components.
Design features
■ Availability of both plug & cage and external
sleeve trims provides interchangeability,
maximum flexibility and lower costs over the
life of the field
■ Thick cross-sections of tungsten carbide
material provide extensive erosion resistance
and reduced wear
■ Robust metal outer cage protects internal
components from slugged flow or impact from
entrained solids during well clean up
■ Trim ports and geometry design reduces
wear and noise, maximizes flow and
controls pressure throughout the choke’s
operating range
■ Pressure-balanced stem and thrust bearings
reduce torque, allowing minimized stem loads
and actuation requirements
The Cameron choke manufacturing facility in Longford, Ireland, has global
responsibility for the design and manufacturing of all subsea chokes and
intervention tooling, as well as subsea chemical-injection metering valves
(CIMV) and gate valve actuators.
This plant is equipped with sophisticated tools and flow control technology,
including CNC machining centers; fabrication and weld-cladding stations;
hydrotest bays; TV-monitored hydrostatic and gas test facilities rated to
30,000 psi; advanced NDE capabilities such as X-ray, UT and PMI; and a
semi-automated blast-and-paint facility.
Our in-house R&D group works hand in hand with sales and manufacturing
teams in 21 countries worldwide, with further support provided by 65
Cameron Services locations. Wherever you need us, we’re already there.
Longford, Ireland
The Cameron electrically actuated Omni-Choke Cameron provides a wide variety of control choke trims
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Because choosing the right trim size is
vital to your success in the field, Cameron
has developed a comprehensive choke
sizing program.
Based on the flow and pressure
requirements of the application, the
software analyzes and specifies the
optimum choke size and trim configuration
for an array of flow conditions.
The Cameron choke sizing program
was developed according to ANSI/
ISA S75.01/02 (IEC 60534-2-1 Mod)
requirements in a specially designed CV
test flow loop.
Choke sizing program
Choke sizing flow loop
Plug & cage trim
External sleeve trim
Reverse flow-in plug & cage
The Cameron choke sizing program
Plug & cage trim
Our plug & cage trim uses a plug that throttles
the flow on the inside diameter of the ported
cage. The tungsten carbide plug assembly in
conjunction with the cage provides optimum
wear resistance in erosive conditions. In
addition, an outer cage provides protection from
impact damage during well cleanup or from
failed downhole completions.
The cage construction enables tungsten carbide
components to withstand the tensile forces
generated during reverse flow. This allows the
trim to be used during production (forward flow)
and injection (reverse flow) applications.
This versatile trim offers excellent erosion
resistance and precise control, making it ideally
suited to deepwater oil or gas production.
Because of its high capacity, the plug & cage
trim design is perfect for flow optimization near
the end of the life of a well.
External sleeve trim
This design incorporates an outer sleeve that
throttles the flow on the outside diameter of the
ported cage. A tungsten carbide flow sleeve and
seat provide optimum wear resistance in erosive
conditions. In addition, a reverse-angle flow
sleeve extends the life of the trim by reducing
annular flow-by.
Field applications have shown this trim to be
the industry leader in erosion performance. In
two separate joint industry projects, Cameron
external sleeve chokes were rated the most
wear-resistant to sand-laden gas or liquified
production service. As a result, this trim is the
preferred solution for severe sand service.
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Multistage anti-cavitation trims
MS three-stage anti-cavitation trim
DBA two-stage anti-cavitation trim
Single-stage pressure letdown Three-stage multistage pressure letdown
Pressure drop profile through one stage. DBA flow characteristics. Minimum pressure (Pvc ) stays above vapor pressure.
Water injection (anti-cavitation) trim
Cameron offers two- and three-stage DBA and
multistage (MS) trims for water injection service.
These custom engineered anti-cavitation trims
can be interchanged with production trims
as required.
The cavitation problem
Cavitation is a serious enemy to efficient flow
control. Cavitation’s destructive effects include
high noise levels, vibration and damage to
valve and trim materials. Cavitation is the
formation and sudden collapse of vapor bubbles
in a flowing liquid. During the liquid’s passage
through a valve, the pressure drops from the
inlet pressure (P) to a minimum pressure (Pvc)
in the vena contracta just past the restriction.
If the Pvc falls below the liquid’s vapor pressure
(Pv), vaporization occurs and vapor bubbles form.
As the liquid moves downstream from the vena
contracta, the pressure recovers to P.
If this outlet pressure, P, is above the vapor
pressure, the vapor bubbles collapse. This causes
high pressure shock waves, which can cause
damage to nearby metal surfaces.
The Cameron solution
Cameron DBA and MS trims were developed
specifically to combat cavitation in water
injection applications. Their multiple pressure
drop design divides the normally large pressure
drop into a series of smaller pressure drops.
Cavitation is eliminated by keeping the pressure
at the vena contracta, Pvc, above the vapor
pressure, Pv, of the liquid. The result is a trim
that eliminates the threat of cavitation, reduces
noise and vibration in downstream pipes and
joints, improves control and performance, and
increases production life.
Pvc Pvc Pvc
P inlet pressure
Vapor pressure
P outlet
pressure
Pressure
Pressure
P inlet pressure
Pvc
Vapor pressure
Cavitation
begins
Vapor formation
P outlet pressure
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