Roxar subsea Sand monitor and Pig detector functional design Owner's manual
- Type
- Owner's manual
Roxar subsea Sand monitor and Pig detector functional design is an acoustic sensor and processing unit contained within an UNS S31803 duplex pressure housing, including a sensing element located at the tip, a preamplifier, digital signal processing, circuitry for detector configuration, with optional 4-20 mA current loop feeding, RS485 serial communication, CAN bus communication and more. Its functions are described and options for interfacing are listed.
Roxar subsea Sand monitor and Pig detector functional design is an acoustic sensor and processing unit contained within an UNS S31803 duplex pressure housing, including a sensing element located at the tip, a preamplifier, digital signal processing, circuitry for detector configuration, with optional 4-20 mA current loop feeding, RS485 serial communication, CAN bus communication and more. Its functions are described and options for interfacing are listed.
Document number:
020085/F
Document name:
Roxar subsea Sand monitor and Pig
detector functional design specification
Scope:
Additional Information (when applicable)
F 11.02.2010
Updated sand calculation formulas,
connector
key orientation and Xylan colour code
Hugo
Barateiro
Gunnar
Wedvich
Morten
Andersen
Bengt
Eliassen
E 25.08.2009 General update
Hugo
Barateiro
Rune
Torma
Morten
Andersen
Bengt
Eliassen
D 08.09.2008 Update coating details, added CP details
Bengt
Eliassen
Gunnar
Wedvich
Morten
Andersen
Bengt
Eliassen
Rev.
index
Issue date Reason for issue Author Review Review
Review
by QA
Approved
Total no. of pages:
22
Document no.: 020085/F
Document
name:
Roxar subsea Sand monitor and Pig detector functional
design specification
Page 2 of 22
TABLE OF CONTENTS
Table of Contents ................................................................................................................... 2
1.
Purpose .......................................................................................................................... 3
2.
Abbreviations................................................................................................................... 3
3.
Roxar subsea acoustic detector .........................................................................................4
3.1
Introduction............................................................................................................. 4
3.2
Detector unit ........................................................................................................... 4
3.2.1
Detector unit in funnel /retrievable version ............................................................. 4
3.2.2
Detector unit in tube fixture /non-retrievable version............................................... 6
3.2.3
Interface connector type ....................................................................................... 6
3.2.4
Oil filled jumper....................................................................................................6
4.
Roxar subsea Sand monitor ..............................................................................................7
4.1
Introduction............................................................................................................. 7
4.2
Mounting location..................................................................................................... 7
4.3
Operation principle and calibration.............................................................................8
4.3.1
Background noise compensation ............................................................................8
4.3.2
Sand calibration....................................................................................................8
4.4
Sand rate calculation ................................................................................................9
4.4.1
Sand calculation input / equations........................................................................ 10
4.5
Detector sensitivity................................................................................................. 11
5.
Roxar subsea Pig detector .............................................................................................. 13
5.1
Introduction........................................................................................................... 13
5.2
Mounting location................................................................................................... 13
5.3
Operating principle................................................................................................. 13
5.3.1
Basic detection principle...................................................................................... 14
5.3.2
Sensitivity .......................................................................................................... 14
5.4
Configuration and set-up ........................................................................................ 14
5.4.1
Configuration ..................................................................................................... 14
5.4.2
Set-up ............................................................................................................... 14
5.5
Debris indicator...................................................................................................... 15
6.
Design specifications ...................................................................................................... 16
6.1
General ................................................................................................................. 16
6.1.1
Detector body .................................................................................................... 16
6.1.2
Funnel ............................................................................................................... 16
6.1.3
Tube fixture ....................................................................................................... 16
6.1.4
Power supply and communication ........................................................................ 16
6.2
Operational features............................................................................................... 17
6.3
Optional ................................................................................................................ 17
6.4
Mechanics.............................................................................................................. 17
6.4.1
General design specifications ............................................................................... 17
6.4.2
Coating and cathodic protection (CP) ................................................................... 18
6.5
Electrical specifications ........................................................................................... 19
6.5.1
Isolation with respect to chassis earth .................................................................. 19
6.5.2
Redundancy ....................................................................................................... 19
6.5.3
Power interface .................................................................................................. 19
6.5.4
Available signal interfaces.................................................................................... 20
6.5.5
EMI susceptibility................................................................................................ 21
6.5.6
Electrical interfaces............................................................................................. 21
6.5.7
Options.............................................................................................................. 21
6.6
Approvals and standards......................................................................................... 22
7.
References .................................................................................................................... 22
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design specification
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1. PURPOSE
This document gives an overview of the Roxar subsea Sand monitor and Pig detector systems.
The following sections describe the main system components, the operational principles and the
functional specifications. Their functions are described and options for interfacing are listed. In
Section 3 it is described the fundamental properties of the detector itself, and is applicable for
both Sand monitor and Pig detector systems.
The mechanical design allow for electronic upgrades and future sensor improvements to be
implemented.
2. ABBREVIATIONS
ANL Average noise level
CIU Calculation and interface unit
CAN Controller area network
CP Cathodic protection
DCS Distributed control system
EMC Electromagnetic compatibility
EMI Electromagnetic interference
GA General arrangement drawing
IDS Instrument data sheet
LSS Layer setting services
MCS Master control system
ROV Remotely operated vehicle
RTU Remote terminal unit
SCM Subsea control module
SPID/SAPD Subsea Pig detector / Subsea acoustic Pig detector
SSAM/SASD Subsea Sand monitor / Subsea acoustic Sand monitor
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3. ROXAR SUBSEA ACOUSTIC DETECTOR
3.1 Introduction
The Roxar SASD and the Roxar SAPD features redundant calculation and interface units (CIU) with
different types of communication for signal monitoring, alarm outputs and software intervention.
The detector has also redundant analogue signal outputs (not valid for versions with CAN bus).
The detector can be equipped with different connectors or electrical adapters. Please see [1],
instrument data sheet, for the electrical interface of your detector.
Available communication types:
4-20mA
KOS150 (with single electronics)
Modbus RTU
CAN bus SIIS level 2
3.2 Detector unit
The detector is an acoustic sensor and processing unit contained within an UNS S31803 duplex
pressure housing, including a sensing element located at the tip, a preamplifier, digital signal
processing, circuitry for detector configuration, with optional 4-20 mA current loop feeding, RS485
serial communication, CAN bus communication and more. The inside of the detector is filled with
dry nitrogen and kept at normal atmospheric pressure. The detector body is double sealed with
metal C-rings and O-rings. To prevent fouling and improve the corrosion resistance of the
detector, the canister body and locking mechanism are Xylan 1070 coated in Roxar standard
colour for subsea canisters (F4210, yellow colour).
The standard electrical interface is an MKII adapter with an oil-filled jumper cable connecting the
detector directly to the subsea pod or to other Roxar instrumentation such as a wet-gas meters or
a multiphase meter. However, the detector may readily be fitted with Tronic or ODI connector
instead of the MKII adapter.
The SASD or SAPD is available with two different mounting arrangements. The equipment can be
delivered as an ROV retrievable version or a fixed (permanent) installed version. The mode of
operation and placement is identical for the two.
Both the funnel and tube fixture installation are permanent and must be completed entirely
topside before template deployment.
3.2.1 Detector unit in funnel /retrievable version
The subsea assembly consists of a non-intrusive detector unit installed in a fixed mounted funnel.
The detector unit is equipped with an ROV handle connected to a spring load locking mechanism
for detector installation in- or retrieval from the funnel.
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When the detector is fixed in the funnel, an acoustic waveguide at the detector tip is kept in
acoustic contact with the outer pipe surface by means of a spring load locking mechanism. During
installation, the detector is grabbed by the ROV handle and guided straight into the funnel. When
the detector tip rests against the pipe surface, the locking mechanism starts compressing the coil
spring and the support wedges centralise the detector body in the funnel. Installation is complete
when the locking pins of the mechanism slides in and hook on to the J-shaped slots in the funnel,
shown in Figure 2. The funnel is equipped with guide marks to indicate detector lock position
Figure 1b). The detector is retrieved by pushing the detector towards the pipe, rotating it counter
clockwise while gently retracting it.
The retrievable unit is equipped with an ROV paddle bar handle and a spring loaded locking
mechanism with lock pins for locking it in the funnel structure. The funnel is mounted on the pipe
with U-bolts and pipe brackets prior to subsea installation.
The detector is equipped with an ROV handle with a paddle type as standard. T-bar, fish tale,
cartesian and hex head are available on request. The ROV handle is Xylan 1070 coated (F1677,
orange colour).
Figure 2 - Funnel J-slot
a)
b) c)
Figure 1 – Retrievable detector unit, funnel and detector in the funnel
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design specification
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3.2.2 Detector unit in tube fixture /non-retrievable version
The detector unit can also be mounted in a more compact tube fixture, Figure 3b). The installation
is permanent and must be completed entirely topside before template deployment.
The unit is mounted permanently, bolted to the tube fixture. The tube fixture and the detector
must be attached to the pipe prior to installation of the subsea template.
This detector is equipped with a different handle than the retrievable version, Figure 3a). The
handle is equipped with two holes used to bolt it to the tube fixture. The lock pins on the
retrievable detector are replaced by pin screws that are installed through the tube fixture wall
when the detector is installed in the tube fixture, Figure 3 c).
a)
b) c)
Figure 3 – Non-retrievable detector unit, tube fixture and detector in the tube fixture
3.2.3 Interface connector type
The standard interface connector type is an Omnitech MKII fitting. Optionally an ODI or a Tronic
connector can be used.
The Tronic connector can have the
following connector key orientation:
• 11 o’clock
• 13 o’clock
• 17 o’clock
• 19 o’clock
3.2.4 Oil filled jumper
An oil-filled jumper cable connects the detector to the subsea pod or to other Roxar
instrumentation such as a wet gas meter or a multiphase meter. At the detector end the jumper is
terminated in an MKII adapter (standard) or a Tronic or ODI subsea connector. Standard options
for the subsea wiring include: Supply (+Ve), Supply Return (-Ve), RS485 +'A' and RS485 –'B' for
serial two-wire RS485 communication and 4-20 mA output Loop (+Ve), and 4-20 mA output Loop
Return (-Ve), CAN Hi and CAN Lo for two-wire CAN bus communication. Please see [1], IDS, for
description of the specific detector electrical interface.
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design specification
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4. ROXAR SUBSEA SAND MONITOR
4.1 Introduction
The SASD system is an acoustic detector that measures sand production in oil, gas or multiphase
pipeline flows. It is installed onto the outside of subsea production pipework in a fixed funnel or
tube fixture. The detector provides real-time quantitative monitoring of sand in production flow,
thus helping the operator to optimise production while limiting erosion of valves, inline process
equipment and flow lines. A sketch of the detector and mounting fixture is shown in Figure 4.
Figure 4 - Sketch of a SASD installed in a funnel
4.2 Mounting location
The funnel shall be attached to the pipe prior to installation of the subsea template. The location
of the funnel shall be close to and downstream of a 90° bend. The installation shall be positioned
such that the detector tip makes contact with the pipe surface just outside of the sand particles
Flow direction
ROV handle
Oil filled jumper
Funnel
Spring loaded locking mechanism
Flow direction
ROV handle
Oil filled jumper
Funnel
Spring loaded locking mechanism
Installation max. 750 mm from 90°
bend
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impact area at the inside of the pipe wall. This is usually on the larger radius, on the outside of the
bend.
In order to achieve the best sensitivity, the detector must be located close, maximum 750 mm, to
a 90° bend as show in the figure.
Installation of the detector should be avoided close to the choke valve, as this valve sometimes
produces unwanted noise that may disturb the detector and cause false sand alarms.
4.3 Operation principle and calibration
The operating principle of the Roxar SASD is based on passive acoustic detection of ultrasonic
noise created by sand particles in the process flow. The detector, located downstream of a bend,
uses the signals generated when sand particles hit the pipe wall to detect and quantify sand
production.
Broadband sand-induced noise will always be superimposed on broadband fluid flow noise and
detector self-noise with frequency content in the same range. Passive acoustic sand detection is
therefore by nature a relative measurement, where the level of 'background noise' needs to be
discriminated and compensated for.
The level of background noise is an increasing function of flow velocity, and is further influenced
by flow parameters such as gas-oil-ratio, water cut, temperature, pressure, etc, as well as piping
and mounting. For the system to function as intended one is therefore fully dependent on a
background noise 'calibration' on site, for each individual detector.
4.3.1 Background noise compensation
Background noise calibration is concerned with finding the 'no sand' reference level of measured
noise as a function of fluid flow velocity. In practice it involves the observation of background
noise level over a set of discrete flow velocities
1
, spanning a representative range, and
establishment of a 'best fit' curve (a third order polynomial) to the data. Noise exceeding this
'Background Noise Curve' at any given velocity is interpreted as being induced by sand.
The background noise curve is expressed as:
DvCvBvAvG +⋅+⋅+⋅=
23
)(
, (1)
where
G(v)
represents the expected background noise level at the present mixed flow velocity,
v
,
and
A
through
D
are polynomial coefficients from the curve fitting.
4.3.2 Sand calibration
The background noise curve defines a 'no sand' reference level as a function of flow rate, and all
noise exceeding the reference is interpreted as being 'sand noise'. Sand calibration is to relate the
level of sand noise to the actual sand production rate by establishing a corresponding velocity
dependent 'Sand Noise Curve'. The curve should represent the expected sand noise level for a
reference rate of 1 gram sand per second, assuming a linear relationship between sand rate and
noise level
2
. As for background noise the sand noise curve is represented by a third order
polynomial:
1
In this context flow velocity refers to a 'mixed' velocity found as the sum of fluid volume flow at actual process
conditions divided by the cross sectional area of the pipe: Velocity = (Qw + Qo + Qg) / Area [m/s]
2
This is a fair assumption for most applications, although not strictly correct. For subsea wells it will not be a
dominating factor in measurement uncertainty.
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HvGvFvEvF
sg
+⋅+⋅+⋅=
23
/1
)(
(2)
The polynomial coefficients
E
through
H
are established by calibration, when possible, or by
default. In practice the relationship is normally defined by tuning in a default curve, incorporating
input such as sand model calculations, sand trap measurements, or other verification where
available.
Note that sand calibration is not required for systems used for sand indication only.
4.3.2.1 Sand model calculations
This method of calibration uses a combination of data from laboratory experience and reference
data from other wells in the same or other fields with similar production parameters. Together
with site-specific parameters, such data is used to model well conditions and to determine sand
calibration coefficients. This method is used when no field reference data is available for the
particular well. This will be the case if there is no present production of sand, or if production or
test schedules do not permit performing other calibration procedures. If the well starts producing
sand at some future point in time, the accuracy of the quantitative measurement can be verified
and improved by re-calibrating the system using sand trap measurements or other reference data.
4.3.2.2 Sand traps
Sand collected in sand traps can be measured and related to the accumulated sand production
recorded by the SASD over the same period of time. The reference data is used to tune in the
sand calibration coefficients of Equation 2. The measured quantity collected in a trap is however
likely to represent only a small proportion of the total sand production during the collection period,
and must be scaled accordingly. The method is suitable for sand-producing wells.
4.3.2.3 Production samples and sand filters
As for sand traps, sand found in production samples or filters may be measured to provide
reference values for tuning of the SASD sand calibration.
4.4 Sand rate calculation
Sand rate is found as:
]/[
)(
)(
/1
sg
vF
vGN
rateSand
sg
−
=
(3)
N = measured noise level (Raw Data) [100 nV]
v = mixed flow velocity [m/s]
G(v) = expected background noise at mixed flow velocity [100 nV]
F(v)|
1 g/s
= expected sand noise for 1 g/s sand rate at present velocity [100 nV]
See also Equations (1) and (2)
The polynomial coefficients of
G(v)
and
F(v)
would normally be found using Service Software and
downloaded to detector memory as configuration parameters for the sand calculation algorithm.
However, for detector interface options where only raw data is communicated topside, the sand
rate algorithm will need to be implemented in the DCS.
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design specification
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4.4.1 Sand calculation input / equations
For detectors supplied with a single 4-20mA current loop output (of raw data) the DCS will first
need to find the raw data noise level
N
based on the measured loop current
n
,see Equation(4). It
is important to note that current loop of each detector will have been configured to give either a
‘Logarithmic’ or ‘Linear’ response. It is necessary to select the appropriate equations accordingly,
see Table 1.
Note that most input parameters are dependent on the detector configuration defined through the
service software. For flexibility one should maintain all these variables in the DCS implementation.
n
Measured loop current [mA] ( 4-20 mA current loop)
MIN
R
Range minimum [100 nV] (corresponding to 4 mA)
MAX
R
Range maximum [100 nV] (corresponding to 20 mA)
v
Mixed flow velocity [m/s]
DCBA ,,,
Background noise polynomial coefficients
HGFE ,,,
Sand noise polynomial coefficients
The 4-20 mA current loop output will have been configured to give either a logarithmic or a linear
response as seen in Figure 5.
Table 1 – Sand calculation equations
Equations Logarithmic 4-20 mA output: Linear 4-20 mA output:
(4)
)4(
16
)20(
16
−⋅+−⋅= n
R
n
R
N
MAXMIN
LOG
)4(
16
)20(
16
−⋅+−⋅= n
R
n
R
N
MAXMIN
LIN
(5)
1000
MAX
R
=∆
---
(6)
∆−
∆+
∆+
⋅∆+=
−
−
MINMAX
MINLOG
RR
RN
MIN
MAX
MIN
R
R
RN )(
LIN
NN
=
(7)
DvCvBvAvG +⋅+⋅+⋅=
23
)(
DvCvBvAvG +⋅+⋅+⋅=
23
)(
(8)
HvGvFvEvF +⋅+⋅+⋅=
23
)(
HvGvFvEvF +⋅+⋅+⋅=
23
)(
(9)
]/[
)(
)(
/1
sg
vF
vGN
rateSand
sg
−
=
]/[
)(
)(
/1
sg
vF
vGN
rateSand
sg
−
=
(4) Measured level (converted from 4-20 mA range)
(5) Delta constant
(6) Noise level (raw data) in [100 nV]
(7) Background noise level [100 nV] expect at the present velocity. Coefficients A through D are established by calibration
(8) Sand noise level [100 nV] corresponding to one gram sand per second at the present velocity.
(9) Sand production rate [g/s]
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Figure 5 - SAM service software used for setup of analogue output
4.5 Detector sensitivity
Sensitivity to particle impact is dominated by two factors:
•
Fluid velocity
•
Particle mass
As a guide, detection may become uncertain at fluid velocities below 1 m/s and particle diameters
below 50 µm. At very large sand rates the particles may tend to form an acoustic barrier on the
pipe wall, limiting the range of maximum detectable sand mass flow. The graph below shows the
nominal minimum and maximum sand production rates that can be accurately measured.
1 ,0 0 E- 0 5
1 ,0 0 E- 0 4
1 ,0 0 E- 0 3
1 ,0 0 E- 0 2
1 ,0 0 E- 0 1
1 ,0 0 E+ 0 0
1 ,0 0 E+ 0 1
1 ,0 0 E+ 0 2
1 ,0 0 E+ 0 3
1 ,0 0 E+ 0 4
1 ,0 0 E+ 0 5
1 ,0 0 E+ 0 6
1 1 0 1 0 0
V e lo c it y ( m /s )
Sand Production (g/s)
G a s M u ltip h a s e
Figure 6 - Sand rate detection limits as a function of mixed flow velocity
R
MIN
R
MAX
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Figure 7 - Sand Rate Detection Threshold in gas flow
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5. ROXAR SUBSEA PIG DETECTOR
5.1 Introduction
The SAPD is a non-intrusive, instrument that provides transport systems personnel with accurate
real-time detection of passing pigs in oil, gas and multiphase pipeline systems. The detector is
spring loaded on to the outside of the pipe.
Figure 8 – Sketch of a SAPD installed in a funnel
The SAPD is based on the detection and interpretation of ultrasonic noise generated by pigs
scraping along the inside pipe wall while passing the detector. The SAPD is truly passive, with no
moving parts or active emission sources. No modifications to the piping or pig are necessary.
The Roxar SAPD is capable to detect all types of pigs, such as cleaning or sealing.
The pig detection system is expandable to practically any number of detectors per site.
5.2 Mounting location
The detector can be installed at any suitable location along the pipe.
5.3 Operating principle
The operating principle is based on passive acoustic detection of ultrasonic noise generated by
moving pigs in the pipeline. The SAPD uses the noise peak arising in the pipe wall when the pig
passes the location of the detector to detect the pig. Detector raw signals and ‘Pig passed’
registrations are stored in a flash memory within the detector. The SAPD does not need to be
hooked up to a computer program for online operation. Signal processing is conducted by the
detector processing unit, and data are stored in a flash memory.
Pig generated noise in the pipe wall
ROV handle Oil filled jumper
Funnel
Moving Pig
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5.3.1 Basic detection principle
When the SAPD is powered, it will automatically start calculating the current ANL (Average Noise
Level) as the noise floor reference. When a pig is approaching the detector, the noise generated
by the pig rises above the ANL. When the noise level exceeds the Li = ANL + Approach Threshold,
the processing unit generates a ‘Pig Approach’ signal. After the pig has passed the detector, the
noise level drops again. When the noise level drops below Lo = ANL + Passed Threshold, the
processing unit generates a ‘Pig Passed’ signal. The Approach Threshold and Passed Threshold can
be set to suit the typical noise level for any type of pig. An example of a pig noise-level during a
passage is shown in Figure 9.
Figure 9 – An example of a Pig passage noise signal
5.3.2 Sensitivity
Pigs generate sufficient noise to allow detection at velocities of approximate 0,05 meter/sec and
upwards. Noise within the ultrasonic frequency band of the sensor will be largely dominated by
that induced by passing pigs, and contributions from other external sources are negligible. This
minimises the risk for spurious and false readings.
5.4 Configuration and set-up
5.4.1 Configuration
Configuration of the SAPD means setting of a unique Slave ID/Node ID (CAN bus), correct Well- or
Tag Name, appropriate output features, and storage configuration.
5.4.2 Set-up
Thresholds and time criteria for reliable pig detection can be changed if default settings are found
to be inappropriate.
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5.4.2.1 Setting of threshold levels
The thresholds Li and Lo are set to suitable levels based on a recorded noise peak signal for the
actual pig type. The procedure is simply to record a raw signal while a pig is passing, analyse the
amplitude of the peak signal, and type in appropriate numbers for Li and Lo.
Once the pig detector is started up, an average noise level (ANL) will be established automatically,
Figure 9. The averaging period and update rate of the ANL is defined by the setting of ‘Average
Noise Level [ANL] Interval’.
Pig approaching is triggered if: Detector signal – Li > 0
Pig passed is triggered if: Pig approaching flag is set and
Detector signal – Lo < 0
5.4.2.2 Setting of maximum and minimum approach time
Certain timing criteria need to be fulfilled for a signal to be recognised and accepted as a Pig
signal. This is to avoid triggering on 'false' pig signals induced by events that are either 'too short'
or 'too long'. (E.g. short spikes from mechanical impacts on the pipe, or a sustained increase in
background noise caused e.g. by changes in flow parameters or heavy rain on the pipe).
The setting of 'Minimum approach time' is to prevent the system from triggering on short
noise peaks.
The setting of 'Maximum approach time' is to prevent the system from triggering on long
lasting changes in the noise level.
If, an increase in the noise level is long lasting (> Max. Approach Time), a new ANL will be
calculated and the system will automatically check if the change in noise level was due to a pig
passed or not. (If the peak signal amplitude > Li + new ANL level, a ‘Pig Passed’ signal will be
generated).
5.5 Debris indicator
The SAPD is equipped with a debris indicator.
When a pig has passed, the Debris Indicator indicates the amount of debris that has been carried
along with the pig. The Debris Indicator number is proportional to the integral of the signal above
the ANL noise line between ‘Pig approach’ and ‘Pig passed’ registrations. The Debris Indicator is
dimensionless, and can be used for comparison of repeated pig runs. The Debris Indicator number
is placed in a register that can be read by the DCS system via the Process bus.
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6. DESIGN SPECIFICATIONS
6.1 General
The Roxar SASD or SAPD is designed to have a lifetime of 25 years.
6.1.1 Detector body
• Material: UNS S31803 (duplex) and A4-80
• Dimensions: Ø=128 mm, H= 506 mm (Retrievable unit), H= 416 mm (Fixed unit)
• Depth: 3000 m
• Max pipe temperature: -40˚C to +225˚C
The detector canister has two primary metal seals, one for the detector front end and one for a
glass sealed electrical penetrator closing the rear end of the detector. Each metal seal have
supplementary O-rings with support rings for seal back-up. Once the canister body is sealed, it is
Helium leakage tested and filled with dry Nitrogen through the canister test port before the port is
sealed off by means of a steel ball seated by a piston screw with double O-rings.
6.1.2 Funnel
• Material: UNS S31603 and A4-80, [2]
• Dimensions: Ø=378mm, H= 402 mm, [2]
• Depth: Any
• Operating temperature: N/A
The funnel assembly is mounted to the pipe with U-bolts. The funnel is equipped with J-slots for
slide in and lock installation of the spring loaded detector by means of an ROV.
6.1.3 Tube fixture
• Material: UNS S31603 and A4-80, [3]
• Dimensions: Ø=168.3 mm, H= 411 mm, [3]
• Depth: Any
• Operating temperature: N/A
The tube fixture is designed for permanent detector installation. It is produced in the same
material as the funnel assembly and deploys the same base plate. The detector is mounted rigidly
with two locking screws, positioning the detector with correct spring force against the pipe.
6.1.4 Power supply and communication
• Supply voltage: 24 VDC
• Communication: See IDS for the exact communication version
• Analog output: 4-20mA
• Serial communication: Modbus RTU
• Serial communication: CAN bus SIIS Level 2
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Document
name:
Roxar subsea Sand monitor and Pig detector functional
design specification
Page 17 of 22
6.2 Operational features
• All signal processing /sand calculations executed in the detector, only processed data needs to
be sent to the surface
• Two way communication
• Redundant signal processing units
• Can download new software configuration & calibration
• Local data storage in detector for 9 days or more (configurable)
• Modbus RTU / RS485 communication line or CANopen SIIS Level 2 communication
• Low bandwidth for data transfer up to MCS (i.e. no large amounts of data transfer required)
• Flexible constant or variable polling intervals allowed
• No software or “black-box” required on surface – data straight into MCS or equivalent
• Functional error checking
• Optional topside Windows software for monitoring, calibration, event log, trending & selectable
output signal in metric or imperial units
6.3 Optional
KOS150:
• Single electronics unit
• One way communication
• Binary RS485 communication line, (1200 bits/sec)
• Sensor identification and raw data output only
• Fixed output update frequency (1/sec)
6.4 Mechanics
6.4.1 General design specifications
6.4.1.1 Detector body
The detector body is designed to be compact, to eliminate the need for welding and to be
directional sensitive to acoustical noise.
Centralizing polymer wedges between the detector and the funnel/tube fixture improve the
acoustic isolation between the two parts, shown in Figure 10. The separation prevents alien
acoustic noise picked up by the funnel/tube fixture from entering the detector.
Figure 10 - Detector with polymer wedges
Polymer
wedges
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name:
Roxar subsea Sand monitor and Pig detector functional
design specification
Page 18 of 22
6.4.1.2 Funnel
The funnel assembly can be separated in two major parts, the funnel and the base plate, where
the base plate is the physical adaptation to the pipe. These two parts are joined together without
welding to prevent weld seam corrosion and to reduce costs. The funnel is attached to the base
plate with 10 x A4-80 bolts.
6.4.1.3 Tube fixture
The tube fixture is designed to save space and utilize the same base plate as the funnel. It is
made from the same material and uses the same bolts (A4-80) to connect the tube to the base
plate.
6.4.2 Coating and cathodic protection (CP)
Internal CP strap length = 100mm:
Cable: Copper cable, Radox 4 GKW-AX, 6mm2 cross section,
Lug: Tin-plated copper lug M6 crimped at the both ends and fitted with heat shrink sleeve
Customer CP Connection Threads, M8
Recommended bolt:
DIN 912, M8x16, A4-80
(Not supplied by Roxar)
The CP surface area exposed to seawater (not including pipe brackets, U-bolts and connector) is:
• Retrievable version - 975000 mm2
• Non-retrievable version - 844400 mm2
Note that Roxar does not supply anodes.
6.4.2.1 Detector unit
The detector unit and the locking mechanism are coated with Xylan 1070. On the retrievable
version a CP continuity strap is introduced between the canister top and one of ROV handle rods;
see Figure
11
(M6 termination at both ends).
Figure 11 - Detector CP Termination Point Figure 12 - CP integrity strap
Cathodic protection of the detector is provided by CP continuity from the funnel, with metallic
contact to the locking arrangement (optionally provided by a separate CP wire through the jumper
hose).
CP
strap point
Document no.: 020085/F
Document
name:
Roxar subsea Sand monitor and Pig detector functional
design specification
Page 19 of 22
6.4.2.2 Funnel
The funnel assembly is coated with Xylan 1070. The funnel base plate is equipped with a M8 CP
termination point for connection to the template cathodic protection system, Figure 13.
Figure 13 - Base Plate CP Termination Point
6.4.2.3 Tube fixture
The tube fixture is to be coated with Xylan 1070. The tube fixture is equipped with the same base
plate as the funnel, with a CP termination point for connection to the template CP system.
6.5 Electrical specifications
6.5.1 Isolation with respect to chassis earth
All pins (electrical connection) are isolated from chassis earth in accordance with the following:
• >1 GΩ (Resistive DC)
• <20 nF (Capacitive)
6.5.2 Redundancy
The Roxar SASD / SAPD features redundant CPU-boards. Each CPU-board has a unique Node ID.
Both are accessible via serial interface.
6.5.3 Power interface
Supply voltage : 24 VDC nominal
Regulation : ± 6 VDC
Protection : Current limit: 340 mA/8.2 W at internal short circuit
Ripple : 400 mV pk-pk
(240 kHz switching frequency)
Power consumption : Versions with 4-20 mA or Modbus: <2.16 W continuous
Version with CAN bus: < 4 W continuous
(check [1], for the specific specification)
6.5.3.1 Transient currents
The detector turn on transient in-rush current profile shall be constrained to ensure that the peak
in-rush current is limited to less than 4 times the nominal sensor operational supply current. In the
02 and 03 version, the in rush current is limited to 2 times the nominal sensor operational supply
current.
CP termination point
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Document
name:
Roxar subsea Sand monitor and Pig detector functional
design specification
Page 20 of 22
6.5.4 Available signal interfaces
6.5.4.1 RS485
• RS485 transceiver ground referenced to DC power source return
Galvanic isolation is NOT normally maintained between the Modbus slave sensor electronics
and the field bus.
• Modbus communications protocol implemented
The bus will be run at 9600 or 19200 bits per second. Both bit rates shall be fully supported by the
sensors electrical and software interface.
The processing unit represents two Modbus slaves in one unit and the two slaves communicate
with an external Modbus master on one common RS485 serial port. This provides full redundancy.
Each slave is given its own name and unique slave ID. Hence, each unit can be addressed with
either of the two IDs. Up to 16 detector units may share the same RS485 communication line.
The 32 Modbus slaves represented by these detectors, must all have different names and slave
IDs. For configuration and set-up of the detector, a service computer running the ‘SAM 400
Service software’ (SAMCIU.exe) would be most convenient as master.
6.5.4.2 4-20 mA
Sensor 4-20 mA current loop is capable of operating from a supply with the following
characteristics:
Supply Voltage : 24 VDC Nominal
Regulation : ± 6 V
Current Limit : 24 mA
Ripple : 400 mV pk-pk
(240 kHz switching Frequency)
6.5.4.3 CAN bus - CANopen
CANopen Higher level protocol on CAN physical layer.
CAN bus SIIS Level 2
Available baud rates 50kBit/s (default) and 125kBits/s selectable via LSS.
CAN applicable standards:
ISO11898-3 Road vehicles – Controller area network (CAN) – Part 3: Low-speed, fault- tolerant
medium dependent interface
According to CIA DS 301 CANopen application layer and communication profile
According to CIA DS 305 Layer settings services and protocol (LSS)
According to CIA DS 443 SIIS Level 2 device profile
6.5.4.4 KOS150 - RS485 serial communication
• RS485 transceiver ground reference to DC Power Source return
• Galvanic isolation is NOT normally maintained between the sensor electronics and the SCM
• Communication baudrate is 1200 bits per second.
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Roxar subsea Sand monitor and Pig detector functional design Owner's manual
- Type
- Owner's manual
Roxar subsea Sand monitor and Pig detector functional design is an acoustic sensor and processing unit contained within an UNS S31803 duplex pressure housing, including a sensing element located at the tip, a preamplifier, digital signal processing, circuitry for detector configuration, with optional 4-20 mA current loop feeding, RS485 serial communication, CAN bus communication and more. Its functions are described and options for interfacing are listed.
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