«Sakhalin-2» Project

TOPSIDES INDUCED ACCELERATION MONITORING SYSTEM FOR OIL AND GAS OFFSHORE PLATFORMS – TIAMS

 

Abbreviations

ADC

Analog Digital Converter

CCM

Calibration control module

CCT-C

Cable Connection Terminal for filed conditions, central

CCT-C

Cable Connection Terminal for filed conditions, remote

DSCPS

System for data storage, control and processing

DSCPS-M

System for data storage, control and processing, modify

ESD

Emergency Shutdown

HMI

Human Machine Interface

ICSS

Integrated Control and Safety System

LUN-A

Lunskoe field

MCC

Measuring – control complex

MER

Main Equipment Room

PA-B

Piltun – Astokhskoe field

PCM

Primary converters module

PCS

Platform Control System

RMS

Remote Measuring system

RMU

Remote Measuring Unit

TIAMS

Topsides Induced Acceleration Monitoring System

UAE

Unified Automatic equipment

UCP

Unit Control Panel

According to the Sakhalin II Project Sakhalin Energy Investment Company is building offshore oil and gas platforms PA-B and LUN-A at the Sakhalin Island shelf.

The platforms are situated within the seismically dangerous area where destructive earthquakes are likely to occur.

To reduce the risk of environmental accidents that can appear during oil and gas production the as a result of destructive earthquake Client took a decision to provide platforms with Topsides Induced Acceleration Monitoring System (further referred as TIAMS).

Institute of the Environmental Geosciences RAS has won the Tender for design, development and manufacturing of the TIAMS arranged by Sakhalin Energy (further referred as SEIC). Basing on the technical assignment Information and Measuring Systems Department, IEG RAS has designed and manufactured in 2005-2006 TIAMS packages for two offshore oil and gas platforms near Piltun – Astokhskoe ( PA_B) and Lunskoe ( LUN-A) fields.

LUN-A and PA-B platforms are very complicated constructions. Each platform has three decks of the football ground size. The platforms are supported by four legs. Their diameters are from 16 to 24 meters , height is approximately 60 m ; depth of the sea at the site is 30...35 m. the lower decks are placed at the height of ~ 27 m , the upper decks are at the height of 50…60 m above the sea surface.

Friction pendulum bearings are placed at the tops of the legs to damp horizontal oscillations under seismic and load impacts to the platform supports.

the main function of the TIAMS is to determine dangerous earthquakes from other impacts induced to the platform ( ice impacts, ship impacts, wave impacts, drill snatch, etc.) that can cause accelerations same to the dangerous earthquakes accelerations at the topsides of the platforms. In case the destructive earthquake has been detected and its acceleration level exceed the threshold of 0,5 g ( assigned by the Client) in any key point of the platform the TIAMS shall initiate the Emergency Shutdown signal ( ESD) .

In such away TIAMS shall provide safety of the oil and gas offshore platforms.

It is necessary to mention that there were no such systems in the world practice between earthquake detection systems that can detect earthquakes from other impacts that can cause the same accelerations as dangerous earthquakes.

IEG RAS has to solve the following tasks during the development and manufacturing that are due to the Client's specifications and platform construction:

  • TIAMS shall work within severe ambient conditions, i.e. minus 40? С ….+50? С in aggressive medium ( salt fogs);
  • TIAMS shall work in the gas dangerous area, i.e. it shall comply with the requirements of intrinsically and explosion proof safety.
  • TIAMS shall comply with the requirements if the IEC 61508 «Electrical, electronic, programmable electronic systems connected with functional safety »;
  • TIAMS shall pass certification to obtain certificates for its elements and overall system;
  • IEG RAS shall simulate all input loads during Factory Acceptance test;
  • IEG RAS shall determine requirements to the frequency and dynamic band of the measured accelerations;
  • IEG RAS shall determine platform responses to the dangerous loads;
  • IEG RAS shall select key points for the placement of sensors to minimize the configuration of the TIAMS.

The solution was based on the Unified automated equipment elements (UAE) designed in the Seismological center by IEG RAS for forecasting polygons of seismic dangerous regions of Russia from 1996-1998 in the frames of the Federal Program “ development of the federal seismic monitoring system and forecasts of earthquakes in 1996-2000” ( for detailed description of UAE see IEG RAS web-site : www.geoenv.ru).

АМЕС ( affiliate of SEIC) has developed mathematical model of the platform in была ABAQUS software and modeled seismic impact to the platform. IEG RAS specialists then formalized all external loads and simulated their impacts for ABAQUS platform models. then IEG RAS specialists analyzed platform responses to the impact loads and earthquakes ( more than 60 thousand diagrams and schemes) .

During the first stage IEG RAS has done the following:

  • Theoretical justification of the external non- seismic impacts to the platform, detection of their features: value and direction of the affecting forces and time dependences.
  • Modeled of 17 variant of impacts using ABAQUS platform model developed by AMEC.
  • Qualitative physical analyses of the topsides responses to the earthquakes and other impacts, detection of the main directions and methods of the mathematical processing of the modeling results.
  • Developed the software program to process modeling results.
  • Analyses of modeling results from seismic and non-seismic impacts.
  • Determined the key point for the sensors and their numbers as 6.
  • Developed requirements for sensors installation.
  • Developed earthquake detection algorithm and algorithm of ESD signal initiation

 

An experience in development of such systems and its operation in the severe environment are very important for solving the same problems at other hazardous ecological objects, such as atomic power plants, chemical plats, high dams and barrages. Such systems can also be used to provide safety of the mega polices.

DESCRIPTION OF THE TOPSIDES INDUCED ACCELERATION MONITORING SYSTEM (TIAMS)

TIAMS block diagram is given at the drawing 1.

TIAMS includes 6 Remote Measuring Units (RMU) and equipments placed in the Unit Control Panel (UCP).

RMU layout is given at the drawings 2, 3, 4. UCP layout is given at the drawings 5 - 6

 

Fig. 2. RMU form

Fig. 3. RMU with open cover

Fig. 4. RMU, view from above, open cover.

Fig. 5. UCP

Fig. 6. UCP, view without back panel

 

RMU content is given in the table 2

Table 2

 

Item

 

 

Quantity

Enclosure

1

Accelerometers Device (AD):

1

Measuring converters Module

3

Patch Board

1

Platform Position transducer

1

Electronic Device (ED):

1

Frequency Characteristic Forming Module

3

Remote Measuring System:

2

Analog-digital Converter Module

2

Micro-Controlling Module

2

Calibration controlling Module

1

Secondary power supply Module

1

Secondary power supply Module, reserved

1

Cable Connection Terminal for Field devices, remote

1

ED Cross-plate

1

Output Terminal

1

Set of the internal connection cables:

 

Connection cable between «Measuring Converter Module/ Patch Board»

3

Flat flexible Connection cable between «Patch Board/ ED Cross-plate»

3

Connection cable between Output Terminal and ED Cross-Plate «ED/ ХТ 1»

1

 

Three – component accelerometers (T А ), RMS, CCT-R are constructively united into the Remote Measuring Unit (RMU), which is designed as the field device permitted to be used in the hazardous environment and severe severity conditions. RMU is located directly in the measuring point.

Fig. 7. Three-component accelerometer (Primary converters module and Frequency characteristic)

The rest elements of the MCC are placed in the Unit Control Panel (UCP) placed in the Main Equipment Room (MER) of the oil and gas offshore platform.

UCP includes the following elements:

Unit

Quantity

Cable Connection terminal for field devices, central (CCT)

CCT 10.00.00

3

System for data storage, control and processing (DSCPS)

DSCPS.00.00.00

6

System for data storage, control and processing, modified (DSCPS-M)

DSCPS.10.00.00

2

Set of the connection cables UCP10.000.00

1

Industrial controlling computer M-MAX700

2

Industrial monitor VT151RM-301-3-00-27

1

RMU Power supply units

QUINT-PS-100-240AC/24DC/10

2

DSCPS, DSCPS-M power supply units QUINT-PS-100-240AC/24DC/10

2

Controlling computer power supply units

QUINT-PS-100-240AC/24DC/10

2

Switch KMV «keyboard- mouse- monitor» VIP-708-KMV

1

Terminals ХТ 1- ХТ 13

13

Internal light system

1

Microclimate control system

1

 

Signals, coming from the RMU to the control panel are transferred by the standard interface RS-485. Date rate through the COM port is 115200 bit/sec. Acquisition and preprocessing of the data received from the RMU is effected in the DSCPS. DSCPS-M carries out the temporary storage of data received from the DSCPS, forms the data blocks in the defined format, processes the information according to the defined algorithm and transfers it through the standard serial interface RS-485 to the controlling computer for registration, viewing and current control of the equipment status. In case the DSCPS-M finds the hazardous seismic event it initiates the ESD signal. Storage and processing of the received information and the viewing are done on the processing computer.

TIAMS is designed for the automatic mode of operation and it provides control and operation of all system elements automatically.

TIAMS has the embed means of diagnostic of the hardware and provides the automatic finding of the emergency situations (at that TIAMS provides the “FAILURE” signal).

The controlling computer and the processing computer provide the human – machine interface (HMI) within the operating system. The processing computer sets the operating modes for the TIAMS and makes changes the configuration. The current status of the system elements, results of the diagnostic, emergency reports, etc are displayed at the monitor.

TIAMS modes

TIAMS has the following operation modes:

  • configuration mode (job assignment);
  • operation mode;
  • testing mode.

Configuring mode allows determining the logic addresses of the RMU, calibration coefficients of the installed accelerometers, thresholds to track the dangerous seismic events, location and length of files with the recorded received data, etc.

After the power supply is switched on the TIAMS proceeds to the operation mode, and the work begins from the selection of the job entered in the configuring mode. After the self – diagnostic and evaluation of the real configuration job adequacy the TIAMS begins to monitor the accelerations in the selected points of the platform, then to analyze the events, and provide the ESD signal initiation when it finds the dangerous earthquake according to the defined algorithm. It also provides the recurring calibration of the accelerometers.

The testing mode allows effecting the detailed examination of the modules capacity for work.

Switching of the system

The system switching is done in three stages as follows:

  • self-testing;
  • job of the configuration parameters;
  • system starting.

Self-testing

On switching all programmable devices of the system (RMS, CCM.DSCPS, DSCPS-M, and Controlling Computer) are running the self-testing and inspection of the connection of the subordinate devices. The test functions of each device are described in the section 'Efficiency monitoring ".

After self-testing and detection of the efficiency of the connected programmable devices, the DCSPS is doing the initial calibration of the accelerometers.

The results of self-testing are transmitted to the seignior devices upon requests.

After self-testing of all modules have been finished, the results are displayed at the screen of the controlling computer and registered in the protocol. The results are as follows:

  • devices' addresses tree;
  • self-testing results of each device: 'no-fault" or list of the malfunctions;
  • calibration results from each accelerometer.

The DSCPS-M passes a "Failure "signal to the PCS in case a malfunction is found. If malfunctions are not resulted in a complete loss of system efficiency, then the system will go on operating with the following restrains:

  • in case of failure of the calibration platform, the calibration shall not be running until
    it will be replaced;
  • in case of failure of one of the accelerometers, the averaging -out shall be done with
    two remained;
  • in case of failure of the RMU or DSCPS, the system will go on operating but the probability of false response will be increased;
  • in case of failure of the active DSCPS-M, its the reserved one takes up its functions;
  • in case of failure of the port or connection line RS-485-1ofthe DSCPS-M the
    connection shall be through the reserved port RS-485-2;
  • in case of failure of the Controlling computer, the doubling takes up its functions;

In case there are no fatal malfunctions, the system proceeds to the assigning of the parameters of configuration, otherwise the system is considered as inoperative until fault removal.

Assigning of the configuration parameters

After the self-testing has been completed, the system checks up the availability of the job assignment with system parameters and its configuration. Parameters are stored in the file with a fixed name at the Controlling computer. If system configuration defined during self-testing concurs with the configuration from the job assignment file, then the automatic start-up of the system shall be done (if there is defined parameter of auto start).

In case there is no file with job assignment, or it is not correct, or it doesn't conform to the system configuration defined during the self-testing then, the system shall wait for the entering of the correct parameters which include the following:

  • Tree of the serial numbers and addresses of the units;
  • Acceleration numeralization frequency;
  • RMS channels in use;
  • Periodicity of testing and accelerometers calibration;
  • Factors of the analogue digital readout conversion into acceleration;
  • Threshold value of the acceleration;
  • Earthquake detection algorithm parameters;

After the correct parameters have been entered, the specialist starts up the system.

System start up

On start up command the following is carried out:

  • time synchronization to the Platform time system;
  • transmission of the job assignment to the subordinate devices.
  • starting of all units.

Efficiency monitoring

Each unit periodically does self-testing and informs the seignior device about results.

Each unit monitors the subordinate devices.

Each unit controls the connection with subordinate units.

Two DSCPS-Ms check the operation of each other and in case of failure of the main DSCPS-M, the other one takes up its functions.

In case any of the DSCPS-M fails then the "FAILURE» signal is initiated.

The information of found malfunctions is displayed at the screen of the controlling computer and registered in the protocol.

All diagnostic can be done in the automatic mode according to the program and under the commands from the operator.

All processor units (RMS, CCM, DSCPS, DSCPS-M and Controlling Computer) have WatchDog timers to prevent the suspension of the program.

RMS and CCM diagnostics.

RMS diagnostic functions

RMS controller carries out the diagnostic of the following:

  • RMS programs memory;
  • RMS data memory;
  • RMS EEPROM memory;
  • efficiency of the analogue digital converter (ADC) of the RMS;
  • conversion frequency error of the RMS ADC;
  • correctness of the job assignment for the RMS ADC;
  • keeps statistic of the faults in the connection line to the DSC PS.

The diagnostic is done in the automatic mode and under the commands from the DSCPS. The results of diagnostic am transmitted to the DSCPS on demands.

CCM diagnostic functions

CCM micro controller carries out the diagnostic of the following:

  • CCM programs memory;
  • CCM EEPROM memory;
  • CCM non-volatile backing memory;
  • availability of the job for calibration of the accelerometers;
  • efficiency of the engine;
  • engine rotation speed;
  • oscillation frequency of the of the calibration platform;
    position of the platform under operation mode;
  • yields a "SELF TEST" signal for electronic test of the accelerometers.
  • keeps statistic of me faults in the connection line to the DSCPS.

The diagnostic is done in the automatic mode and under the commands from the DSCPS. The results of diagnostic are transmitted to the DSCPS on demands

DSCPS diagnostic functions

DSCPS micro controller carries out the diagnostic of the following:

  • DSCPS programs memory;
  • DSCPS data memory;
  • sends the commands for testing and calibration of the RMU (RMS and CCM);
  • requests the results of the diagnostic from RMU;
  • analyses the data of accelerometers and estimates their efficiency and calibration parameters;
  • analyses the efficiency of connection line with RMU;
  • keeps the statistic of the faults in the connection line to the DSCPS-M

The diagnostic is done in the automatic mode and under the commands from the DSCPS-M. The results of diagnostic are transmitted to the DSCPS-M on demands

DSCPS-M diagnostic functions

DSCPS-M micro controller carries out the diagnostic of the following:

  • DSCPS-M programs memory;
  • DSCPS-M data memory;
  • sends the commands for testing and calibration to all DSCPS;
    requests the results of the diagnostic from DSCPS;
  • analyses the efficiency of connection line with all DSCPS;
  • analyses the efficiency of the redundant DSCPS-M.
  • keeps the statistic of the faults in the connection line to the redundant DSCPS-M
    analyses the efficiency of the main and redundant controlling computer
  • keeps the statistic of the faults in the connection line to the main and redundant controlling
    computer;
  • analyses the efficiency of me connection line to the main and redundant controlling computer;
  • controls the regularity of the secondary power supply sources.

The diagnostic is done in the automatic mode and under the commands of the controlling computer.

The results of diagnostic are transmitted to the controlling computer on demand. In case of failure the DSCPS-M initiates the "Failure "signal to the PCS.

Controlling computer (CC) diagnostic functions

The CC carries out the diagnostic as following:

  • passes the job for caring out of the automatic diagnostic and calibration to the subordinate devices;
  • passes the job for caring out of the automatic diagnostic and calibration to the subordinate device on command from operator,
  • collects the results of diagnostic of all devices from DSCPS-M.
  • displays at the screen the status of all units.
  • registers in protocol the reports of all malfunctions and reestablishment of operation.
  • controls 3 levels of access to work with TIAMS by the systems of passwords.

All functions of diagnostic and data storage are carried out at the same time at the main and redundant controlling computer. The commands can be given from any of the controlling computers,

Laptop diagnostic functions

Laptop provides the possibility to do the autonomic diagnostic of the system modules (RMU, DSCPS, DSCPS-M) that are under repair or spared.

 

appdev_page2-eng_clip_image002.jpg

Fig. 1 TIAMS block diagram

 

RMU Technical Characteristics .

RMU technical characteristics are given in the table 3.

#.

Description

Value

1.

Number of orthogonal acceleration measuring axes

3

2.

Number of three-component accelerometers

3

3.

Amplitude range of the measured acceleration, m/s2

0,03…30,00

4.

Frequency range of the measured acceleration, Hz

0,1…10

5.

Numeralization capacity of the measured accelerations, bit

24

6.

Least significant Bit Average Weight at frequency of 1 Hz, m/s2

4,33 x 10-6 ± 10%

7.

Maximum sampling frequency of the measured accelerations, Hz

200

8.

Maximum information rate, Кbit/sec

115,2

9.

Interface type

RS-485

10.

Maximum length of the connection line to UCP, m

1200

11.

Voltage of the primary power-supply source, V.

9...30

12.

Power consumption under the measuring mode, not more than, Watt

2 5,0

13.

Power consumption under the calibration mode, not more than, Watt

35 ,0

14.

Overall dimensions, mm.

 

 

Length
632
Width
432
Height
335

15.

Weight, kg, not more than

65

16.

УService conditions*:

 

  • Temperature, ° С
от минус 40 до 55
  • Relative humidity, ambient temperature 35 ° С, %
95 ± 3
  • •  Atmospheric pressure, kPa

84-106,7

-Strength under the sinusoidal vibration impact of:

  • Frequency, Hz

10-55
  • Displacement amplitude, mm

0,15
- Impact resistance under the loads of mechanical impacts:
  • Multiple (duration 2-50 msec), m/s2
100
  • Single ( duration 0,5 – 30 msec) m/s2
150

17.

Continuous running time

неограничено

18.

Warranty assurance, month

24

19 .

Ingress Protection Rate according to the IEC 60529

IP 67

20.

Explosion – proof rate

1 ExdIIBT6

Tree – component accelerometers do the conversion of the current values of the accelerations into output voltage through three mutually perpendicular axes.

Each accelerometer has the self-testing and calibration devices.

The self-testing is based on the sensing device inertial mass position changing upon the command “Self-test” and under the impact of the electrostatic force that approximately equal to the 20% of the calibration measuring range (full scale). This is the way to check the efficiency of the overall mechanical structure and electric circuit of the accelerometer.

Electric motor with reducer, driving gear, calibration platform, platform position transducer and calibration control module form the calibration unit that provides the calibration mode under which the position of the calibration platform should be changed according to the assigned principle. Control on the calibration and self-testing of the three-component accelerometer is done by the Calibration Control Module that forms the “Self-Test” signal and drives the electric motor (sets in motion the calibration platform). The CP is intended for the placement, fastening and mutual orientation of tree Measuring Converter Modules. It is fixed at the bearings that installed at the platform supports. CP could change its position relatively to the long axis within the range of 0?…+45?. The moment that provides the oscillation movements of the platform revolving on its axis is passed by the crank- link mechanism that connects the drive shaft of the electric motor and CP. The oscillation frequency of the CP is equal to the value of the central frequency of the working range, which is 1,0 Hz. The Platform position transducer is used to provide the return of the platform to its starting (measuring) position. The signal of this transducer is used by CCM to control the operation of the electric motor.

The calibration of the accelerometer-measuring channel is based on the periodical (with the frequency of 1 Hz) changing of the initial accelerometer converters position. These initial accelerometer converters are included into the Measuring Converter Module that is placed at the CP. This method shows the changing of the gravitational acceleration projection to the sensor sensitive axis. Variations amplitude of this projection is about 0,15g (1,5 m/s2) and serves as the calibration constant. The value of the calibration constant is a reference value for the periodical calibration of the accelerometer measuring channels.

Two Remote Measuring Systems do the conversion of the output analog signals from the tree –component accelerometers into the digital code. Each RMS contains of Analog Digital Conversion Module and Micro-Controlling Module, which control the analog-digital conversion process, self-testing, receiving and transmission of the data.

The changing of the acceleration amplitude, testing and calibration are effected upon the commands from the UCP according to the operation software of TIAMS.

During the implementation of the contract TIAMS has received the following certificates:

  1. Permission for use from Rostekhnadzor
  2. EMC certificate
  3. Explosion proof certificate
  4. Type approval certificate for system elements (RMS, DSCPS, CCT-C, CCT-R)
  5. Type approval certificate for overall system is in process of issuing
  6. Type approval certificate for three-component accelerometer is in process of issuing
  7. IEG RAS has obtained Quality Management certificate ISO 9001.