K-POS Riser Angle Monitoring

Kongsberg K-PosRiser Angle Monitoring

Operator ManualRelease 7.1

322303/CAugust 2010 © Kongsberg Maritime AS

Document history

Document number: 322303

Rev. A October 2008 This version describes the operation of the Riser AngleMonitoring at K-Pos basis software release 7.1.0.

Rev. B June 2010 Updated to basis software release 7.1.7 and new KM stylesheet.

Rev. C August 2010 Hold Flexjoint Angle (HFA) function removed.

The readerThis operator manual is intended as a reference manual for the system operator. This manual is based onthe assumption that the system operator is an experienced DP operator with a good understanding of basicDP principles and general DP operation. If this is not the case, then the operator should first attend theappropriate Kongsberg Maritime training courses.

NoteThe information contained in this document remains the sole property of Kongsberg Maritime AS. Nopart of this document may be copied or reproduced in any form or by any means, and the informationcontained within it is not to be communicated to a third party, without the prior written consent ofKongsberg Maritime AS.Kongsberg Maritime AS endeavours to ensure that all information in this document is correct and fairlystated, but does not accept liability for any errors or omissions.

WarningThe equipment to which this manual applies must only be used for the purpose for which it wasdesigned. Improper use or maintenance may cause damage to the equipment and/or injury to personnel.The user must be familiar with the contents of the appropriate manuals before attempting to operateor work on the equipment.Kongsberg Maritime disclaims any responsibility for damage or injury caused by improper installation,use or maintenance of the equipment.

CommentsTo assist us in making improvements to the product and to this manual, we welcome comments andconstructive criticism.e-mail: [email protected]

Kongsberg Maritime ASwww.kongsberg.com

Operator Manual

Table of contents

Glossary....................................................................................................................5OVERVIEW........................................................................ 9Introduction ..............................................................................................................9Riser sensors.............................................................................................................9Position Advisory function..................................................................................... 11Emergency Joystick Advisory (EJA) function ....................................................... 11Drilling Alarm Settings ..........................................................................................12Tensioner stroke sensors.........................................................................................12Simulator and trainer features ................................................................................12Definitions and abbreviations .................................................................................12OPERATING PROCEDURES .............................................. 13RAM settings..........................................................................................................13Entering well data...................................................................................................14Enabling and calibrating RAM sensors..................................................................14

Enabling ERA riser sensors ......................................................................... 15Enabling ERA BOP sensors......................................................................... 16Enabling ARA riser sensors......................................................................... 17Calibrating sensors...................................................................................... 19

Drilling Configuration ............................................................................................20Selecting sensors for composite angle calculations ........................................ 20Enabling the Emergency Joystick Advisory (EJA) function ........................... 21

Entering drilling warning and alarm limits ............................................................22Enabling riser difference angle limits .......................................................... 22Defining an illegal heading sector ............................................................... 23Enabling output signal to external alarm for position limits............................ 24Having RMS alarms issued through the K-Pos system................................... 24

Selecting drilling display options ...........................................................................24Saving and reading RAM settings..........................................................................25Using the Position Advisory function ....................................................................26

Enabling the Position Advisory function....................................................... 26Indication of advised positions on the Posplot view....................................... 27

Using the Emergency Joystick Advisory (EJA) function.......................................29Conditions for displaying the EJA arrows..................................................... 29Preparations for running the EJA function .................................................... 30Indication of the EJA arrow on the Posplot view........................................... 31

DISPLAYED RISER ANGLE INFORMATION....................... 32Drilling Sensors dialog box....................................................................................32Riser Angle Monitoring - Sensor List dialog box ..................................................32

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Riser Angle Monitoring

Sensors dialog box - Tensioner page ......................................................................34Posplot view ...........................................................................................................35

Displayed positions..................................................................................... 36Illegal heading sector .................................................................................. 37

Riser view...............................................................................................................37View controls ............................................................................................. 40

Driller view.............................................................................................................43View controls ............................................................................................. 46

RMS Summary view ..............................................................................................51View Controls............................................................................................. 55

SYSTEM MESSAGES......................................................... 58RAM system messages...........................................................................................58

Riser difference angle limit violation............................................................ 58Illegal heading sector limit violation ............................................................ 58Sensor measurement error ........................................................................... 59

RMS messages .......................................................................................................59RMS UFJ out of limits ................................................................................ 59RMS stroke out of lower limits .................................................................... 59RMS top tension out of lower limits............................................................. 59

SIMULATOR AND TRAINER ............................................. 60Special simulator and trainer features ....................................................................60

Sensor biasing ............................................................................................ 60Vessel relative position of the upper flexjoint ................................................ 60

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Operator Manual

Glossary

Abbreviations

API RP American Petroleum Institute Recommended Practice

ARA Acoustic Riser Angle

BOP Blow Out Preventer

DTL Dynamic Tension Limit

EJA Emergency Joystick Advisor

ERA Electrical Riser Angle

FJA FlexJoint Angle

LFJ Lower FlexJoint

LRJ Lower Riser Joint

RAM Riser Angle Monitoring

UFJ Upper Flexjoint Angle

WSF Worst Single Failure

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General terms

Angle reference Either a reference sensor or the manually configured BOPinclination angle.

Bearing The angle between the riser (BOP) and the X-coordinate of itscoordinate system, when the riser (BOP) is projected onto thehorizontal plane.

BOP angle The angle between BOP and a vertical line.BOP Composite A low pass filtered BOP angle, based on all enabled and accepted

BOP sensors that are selected for composite angle calculations.The filter constant can be controlled by the Noise Filter.

BOP sensor Angle-measurement sensor attached to the BOP.CompositePositionAdvisory symbol

A symbol shown on the Posplot view indicating the calculatedposition where the composite lower riser difference angle asmeasured by the riser sensors would be zero.

Compositezero-angleposition

Same as zero-angle-position, but now based on the compositeriser angle and composite BOP angle.

EJA arrow When the EJA function is active, this is the arrow on the Posplotview indicating the direction in which manual thrust must beapplied to move the vessel towards an advised position calculatedby the Position Advisory function.

Limit set A set of warning and alarm limits for riser deflection. There canbe several preconfigured limit sets. One or more riser sensorscan be associated with each of these limit sets. The limit valuescan be changed by the operator.

Lower flexjoint The riser flexjoint that is closest to the BOP.Noise Filter A low pass filter constant used for updating composite angles.

When entering the filter constant value, only values from 1.0 to100.0 will be accepted. A value of 1.0 gives no filtering.

PositionAdvisoryfunction

Uses the riser angle measurements to calculate a vessel positionthat will bring the Riser Difference Angle to zero.

PositionAdvisory symbol

General term for a position symbol shown on the Posplot view,for example the Composite Position Advisory symbol or one ofseveral Individual Position Advisory symbols.

Position dropout A phrase used to describe the situation that arises, when thesystem has lost all acceptable position-reference information.

RAMconfigurationfile

The file used to store setup values for the RAM function.

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Operator Manual

Referencesensor

A sensor used as reference for the riser measurements. Willnormally be a BOP sensor.

Riser angle The angle between the riser and a vertical line.

Riser Composite A low pass filtered riser angle, based on all enabled and acceptedriser sensors that are selected for composite angle calculations.The filter constant can be controlled by the Noise Filter.

Riser differenceangle

The difference between the Riser angle and the angle of itsreference sensor.

Riser sensor An angle measurement sensor attached to the riser.

Upper flexjoint The riser flexjoint that is closest to the vessel.

UFJ point The upper flexjoint point, i.e. the riser-to-vessel connection point.

X-angle Riser (or BOP) angle when the riser (BOP) is projected onto theXZ-plane. When the X-angle is zero, the riser (BOP) is in theYZ-plane, and when the X-angle is 90 degrees, the riser (BOP) isin the XY-plane (horizontal plane).

Y-angle Riser (or BOP) angle when the riser (BOP) is projected onto theYZ-plane. When the Y-angle is zero, the riser (BOP) is in theXZ-plane, and when the Y-angle is 90 degrees, the riser (BOP) isin the XY-plane (horizontal plane).

zero-angleposition

The vessel position that will result in either a zero absolute riserangle or a zero riser difference angle, based on one single riserangle sensor and its Angle reference.

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Overview

Overview

This section contains the following topics:Introduction........................................................................................................................9Riser sensors ......................................................................................................................9Position Advisory function .............................................................................................. 11Emergency Joystick Advisory (EJA) function ................................................................ 11Drilling Alarm Settings....................................................................................................12Tensioner stroke sensors ..................................................................................................12Simulator and trainer features..........................................................................................12Definitions and abbreviations ..........................................................................................12

IntroductionRiser Angle Monitoring (RAM) allows optimised vessel position during drillingoperations. The various functions are described in the following sections. Text incapitals refers to items in Figure 1.

Riser sensorsFigure 1 provides an overview of the angles that are measured.

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Figure 1 Riser angles

BOP POSITION UPPER FLEXJOINT (UFJ)

LOWER FLEXJOINT (LFJ)

X

Y

Z

UPPER FLEXJOINT LEVEL

SEA LEVEL

BOP ANGLE

RISER

BOP

RISER HEIGHT

RISER ANGLE

RISER DIFFERENCE ANGLE

ADVISED POSITION(VESSEL POSITION FORZERO RISER DIFFERENCE ANGLE)

RISER

(CD3315)

The BOP is a fixed structure on the sea bed. The angle between the center line of the BOPand a vertical line is called the BOP ANGLE (also known as the riser reference angle).This angle is either measured by sensors attached to the BOP or specified manually.

The riser, which is assumed to be a rigid structure, is connected to the vessel at theUPPER FLEXJOINT, and to the BOP at the LOWER FLEXJOINT. The RISERANGLE, at the lower flexjoint, between the riser and a vertical line, is measured bysensors attached to the riser.

The RISER DIFFERENCE ANGLE, at the lower flexjoint, between the riser and thecenter line of the BOP, should be kept to a minimum to reduce mechanical wear. Thisangle is zero when the vessel is located at the ADVISED RISER POSITION.

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Overview

The sensors may be either Electrical Riser Angle systems (ERA) or Acoustic RiserAngle systems (ARA).

The monitoring is based on measurements of the RISER DIFFERENCE ANGLE. Toprovide redundancy in the angle measurements, there are usually at least two riser andtwo BOP sensors. The riser sensors and BOP sensors are generally configured in pairs,each pair being mounted in corresponding monitoring positions on the riser and BOP.The RISER DIFFERENCE ANGLE, and therefore the ADVISED RISER POSITION,is computed for each riser/BOP sensor pair. Each sensor pair is given a name (such asYellow and Blue).

The BOP and riser sensors usually provide measurements in two different coordinatesystems. Both coordinate systems have their origin at the lower flexjoint, with the Z axisvertically downwards, but the X and Y axes may be rotated.• For each BOP sensor, you must specify the orientation of the sensor coordinate

system in relation to North (unless the sensor measurements incorporate a compassmeasurement).

• For each riser sensor, you must specify the orientation of the sensor coordinatesystem in relation to the coordinate system of the corresponding BOP sensor or themanually-entered BOP position.

The sensors may provide measurements in the following forms:• Inclination (angle from the vertical) in the X direction, and inclination in the Y

direction.• Inclination in a specified direction (bearing) in relation to the X axis.

To allow for inaccuracies in the installation of the sensors, you can specify bias valuesfor the angle measurements.

Position Advisory functionThe Position Advisory function uses the riser angle measurements to calculate the vesselposition that will bring the RISER DIFFERENCE ANGLE to zero.

The Position Advisory function gives one zero-angle position for each interfaced andenabled angle sensor set, and also a composite position which is calculated using theaverage of the accepted sensors selected for composite zero-angle-position calculation.See Using the Position Advisory function on page 26.

Emergency Joystick Advisory (EJA) functionThe Emergency Joystick Advisory function (EJA) can be activated in Auto Position(during position dropout) and Joystick modes. The EJA provides a graphical indicationon a relative Posplot view, of the direction in which joystick thrust must be applied to

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move the vessel towards the advised position. This position is calculated by the PositionAdvisory function. See Using the Emergency Joystick Advisory (EJA) function onpage 29.

Drilling Alarm SettingsThe Drilling Alarm Settings dialog box allows you to enter warning and alarm limits forcalculated riser difference angle, and to define an illegal heading sector.

Tensioner stroke sensorsYou can use the Tensioner page (see Figure 16) on the Sensors dialog box to:• Enable the tensioner stroke sensors• Set and enable upper and lower sensor tension limits• Monitor dynamic tensioner stroke sensor values and status.

A maximum of eight tensioner stroke sensor readings are also shown both graphically(bar-graphs) and numerically on the Riser view (see Figure 18). The upper and lowerlimits are shown on the bar-graphs in this view.

Simulator and trainer featuresSpecial features are provided to allow Riser Angle Monitoring when running the systemin Trainer or Simulator mode. See Special simulator and trainer features on page 60.

Definitions and abbreviationsRefer to the Glossary at the front of this manual for a complete overview.

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Operating procedures


This section contains the following topics:RAM settings ...................................................................................................................13Entering well data ............................................................................................................14Enabling and calibrating RAM sensors ...........................................................................14Drilling Configuration......................................................................................................20Entering drilling warning and alarm limits......................................................................22Selecting drilling display options ....................................................................................24Saving and reading RAM settings ...................................................................................25Using the Position Advisory function..............................................................................26Using the Emergency Joystick Advisory (EJA) function ................................................29

RAM settingsThe following sections describes how to set up and use the following Riser AngleMonitoring functions:• Entering well data• Enabling and calibrating riser sensors and BOP sensors (RAM sensors)• Selecting sensors for composite angle calculations• Defining warning and alarm limits• Selecting drilling display options• Saving and reading RAM settings• Using the Position Advisory function• Using the Emergency Joystick Advisory (EJA) functionNote

The dialog boxes shown in this section are examples that are designed to illustratethe available options. The actual number and configuration of sensors may vary fromsystem to system.

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Entering well dataIn the Well Data dialog box you can enter the following data:• BOP position• Vertical distance from Upper Flex Joint (UFJ) to Lower Flex Joint (LFJ)• Manual values for the BOP angle, bearing and orientation. These manual values are

used when the BOP sensor to which a riser sensor refers, is not enabled.Select Driller→Well Data. TheWell Data dialog box is displayed.

Figure 2 Well Data dialog box

Position

The coordinates of the BOP position. Click the N button to switch between northand south coordinates, and click the E button to switch between east and westcoordinates.

Vertical distance from UFJ to LFJ

Vertical distance The vertical distance between the upper and lower flexjoint (seeRiser angles on page 10).

BOP/Stack

Angle

Manual value for the BOP angle (in the direction of Bearing).Bearing

Manual value for the direction of the BOP Angle in relation to the X-axis.Orientation

The compass direction of the BOP coordinate system.

Enabling and calibrating RAM sensorsThe information presented in the Drilling Sensors dialog box depends on the type ofmeasurements received from the sensor:

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• Angle and bearing measurements• X and Y inclination measurements

Enabling ERA riser sensorsSelect Drilling→Sensors. The Drilling Sensors dialog box is displayed.

Click the ERA Riser tab. The ERA Riser page is displayed.

Figure 3 Drilling Sensors dialog box - ERA Riser page

Sensor Name

Type and name of the sensors.OK

The OK status of the sensor. For information only.Enable

Select this check box to enable measurements from this sensor.Meas. Type

The types of measurements from the sensor.Biased Values

Depending on the configuration, either Ang (Angle) and Bear (Bearing), or X-incland Y-incl are displayed.

Ang

The riser angle (in the direction of Bear (Bearing)) as measured by this sensor,adjusted for the specified Bias value.Bear

The direction of the riser Ang (Angle) as measured by this sensor, relative to thesensor X-axis, adjusted for the specified Bias value.X-incl

The riser angle in the X direction as measured by this sensor, adjusted for thespecified Bias value.

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Y-incl

The riser angle in the Y direction as measured by this sensor, adjusted for thespecified Bias value.

Bias

Bias value to compensate for inaccuracy in the installation of the sensor. Manuallyentered or calculated when the sensors are calibrated.

Orientation Rel. Base

The orientation of the riser sensor coordinate system in relation to the coordinatesystem of the Base.

Base

The designation either of the corresponding BOP sensor or manual BOP data.Filter Constant

This value is used to filter the sensor measurements that are presented in thedisplay views and in the Riser Angle Monitoring - Sensor List dialog box. Unfilteredmeasurements are shown on the Drilling Sensors dialog box.

Enabling ERA BOP sensorsSelect Drilling→Sensors. The Drilling Sensors dialog box is displayed.Click the ERA BOP tab. The ERA BOP page is displayed.

Figure 4 Drilling Sensors dialog box - ERA BOP page

Sensor Name



Select this check box to enable measurements from this sensor.Meas. Type

The types of measurements from the sensor, in this instance Angle, Bearing andOrientation.

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Biased Values

Depending on configuration, Ang (Angle) and Bear (Bearing), or X-incl and Y-inclare displayed:

Ang

The BOP angle (in the direction of Bear (Bearing)) as measured by this sensor,adjusted for the specified (or calculated) Bias value.Bear

The direction of the BOP Ang (Angle) as measured by this sensor, relative to thesensor X-axis, adjusted for the specified (or calculated) Bias value.X-incl

The BOP angle in the X direction as measured by this sensor, adjusted for thespecified Bias value.Y-incl

The BOP angle in the Y direction as measured by this sensor, adjusted for thespecified Bias value.Orientation

The orientation of the BOP sensor coordinate system relative to North.Bias


Filter Constant


Enabling ARA riser sensorsSelect Drilling→Sensors. The Drilling Sensors dialog box is displayed.

Click the ARA tab. The ARA page is displayed.

Figure 5 Drilling Sensors dialog box - ARA page

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Sensor Name



Select this check box to enable measurements from this sensor.Tp. ID

Transponder identifier. Select a Tp. ID from the drop-down list.Diff.

This check box is selected when the ARA riser sensor is a riser difference sensor.This check box is for information only, and cannot be selected/deselected by theoperator.Riser difference sensors produce measurements of the riser difference angledirectly (already adjusted for BOP tilt and relative to North). This type of sensordoes not require a corresponding BOP sensor.The following exceptions to riser sensors apply:• The coordinate system for this riser difference sensor is already related to the

North direction, and therefore an Angle Reference is not relevant. Any knownoffset between the sensor coordinate system and the North direction can beentered in Orientation Rel Base.

• The Zero Angle Position can be calculated only for the Riser Difference Angle.• A difference sensor cannot be part of composite riser angle calculations.

Biased Values

Depending on configuration, Ang (Angle) and Bear (Bearing), or X-incl and Y-inclare displayed:

Ang

The riser angle (in the direction of Bear (Bearing)) as measured by this sensor,adjusted for the specified Bias value.Bear

The direction of the riser Ang (Angle) as measured by this sensor, relative to thesensor X-axis, adjusted for the specified Bias value.X-incl

The riser angle in the X direction as measured by this sensor, adjusted for thespecified Bias value.Y-incl

The riser angle in the Y direction as measured by this sensor, adjusted for thespecified Bias value.

Orientation Rel. Base

The orientation of the riser sensor coordinate system in relation to the coordinatesystem of the Base.

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Bias


Base

The designation either of the corresponding BOP sensor or manual BOP data.Filter Constant


Calibrating sensorsSelect Drilling→Sensors. The Drilling Sensors dialog box is displayed.

Click the Calibration tab. The Calibration page is displayed.

Figure 6 Drilling Sensors dialog box - Calibration page

Riser

The correct riser orientation (as Angle and Bearing, or as X-incl and Y-incl). Youmust enter these values before starting automatic sensor calibration for the SelectedSensors.

BOP

The correct BOP orientation (as Angle and Bearing, or as X-incl and Y-incl). You).You must enter these values before starting automatic sensor calibration for theSelected Sensors.

BOP Orientation

The compass direction of the BOP coordinate system.Available Sensors

A list of enabled sensors. To select a sensor for calibration, click the requiredsensor and then click the Add-> button. Several sensors can be calibratedsimultaneously. To remove a sensor from the Selected Sensors list, click therequired sensor and then click the <-Rem button. To add or remove all sensors,click the All-> or <-All button, respectively.

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Calibration Period

Specify the calibration period (in seconds) for automatic sensor calibration. Sensormeasurements will be averaged over the Calibration Period, and then compared tothe specified Riser Orientation and/or BOP Orientation.

Start Calibration

Click this button to start the automatic calibration of the selected sensors. Thecalibration process starts. During the Calibration Period, the text on the buttonchanges to Cancel Calibration and the field to the right of the button shows theprogress graphically. See Figure 7.

Figure 7 Automatic calibration of selected sensors in progress

When the calibration is completed, an information message displayed.

Figure 8 Information message confirming completed sensor calibration

For all enabled sensors selected for calibration, the average sensor measurementsduring the Calibration Period will be compared to the operator-defined RiserOrientation and/or BOP Orientation. The difference will then be entered into therespective Bias text boxes for each sensor.

Note

Before activating the bias values, check that the bias values on all three pages of theDrilling Sensors dialog box are correct.

To activate the new bias values, click the OK or Apply button on the Drilling Sensorsdialog box.

Drilling Configuration

Selecting sensors for composite angle calculationsAn average low-pass filtered riser angle can be calculated. Using the DrillingConfiguration dialog box, you can select the sensors to be included in the calculation.

Select Drilling→Configuration. The Drilling Configuration dialog box is displayed.

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Note

This dialog box (as most dialog boxes in this DP system) has input validation. If illegalvalues are entered in any of the text boxes, a message is displayed (when you haveclicked the OK or Apply button) informing you about the error and about the legal values.Rectify the value(s), and click the OK or Apply button again.

Figure 9 Drilling Configuration dialog box

Available Sensors

A list of enabled sensors. To select a sensor for Composite Angle Calculation,click the required sensor and then click the Add-> button. To remove a sensor fromthe Selected Sensors list, click the required sensor and then click the <-Rem button.To add or remove all sensors, click the All-> or <-All button, respectively.

Noise Filter (1-100)

A low pass filter constant used to update the composite riser and BOP angles. Avalue of 1.0 gives no filtering, and the composite value will be set equal to theaverage measured value. A value of 100 gives maximum filtering (which limitsthe contribution of the most recent measurements).

Enabling the Emergency Joystick Advisory (EJA) functionThe Emergency Joystick Advisory function is described in detail in Using the EmergencyJoystick Advisory (EJA) function on page 29.Enable EJA Function

Select this check box to enable the EJA function.

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Entering drilling warning and alarm limitsThe Drilling Alarm Settings dialog box allows you to enter warning and alarm limits forcalculated riser difference angle, and to define an illegal heading sector.

Select Drilling→Alarm Settings. The Drilling Alarm Settings dialog box is displayed.

Figure 10 Example Drilling Alarm Settings dialog box

Enabling riser difference angle limitsYou can select among preconfigured limit sets for riser difference angle, where each setis given a specific name (e.g. Lower Flexjoint or Upper Flexjoint). One or more sensorsis preconfigured with each of these limit sets. This implies that a riser sensor that isnot associated with a limit set, will not be monitored against any angle limits. For aselected limit set, you can specify warning and alarm limits for the calculated riserdifference angles. Each of the calculated angles are monitored against these limits. Ifa limit is exceeded, and the limits for a set are enabled, a warning or alarm message isissued, for example:

Riser angle out of limits ERA blue 3.1 3.0

Additional information in the message shows the name of the riser sensor, the riserdifference angle (at the time when the limit was first exceeded) and the angle value ofthe limit that is exceeded.

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Note

The titles used for the warning and alarm limits vary depending on configuration.

The Riser view (see Figure 18) and the Driller view (see Example Driller view onpage 44) show the riser angle limits for the selected limit sets.Select Limit Set

Select the limit set to be used from the drop-down list.Sensors in Limit Set

A list of riser sensors associated with this limit set.Warning

Enter the warning limit for the selected limit set.Alarm 1

Enter the first alarm limit for the selected limit set.Alarm 2

Enter the second alarm limit for the selected limit set.Alarm 3

Enter the third alarm limit for the selected limit set.

Note

The definition of each of the above limits as a warning or as an alarm limit, andalso the number of defined limits, vary depending on configuration.

Enable Limits

Select this check box to enable the riser angle warning and alarm limits for theselected limit set.

Note

You can enable warning and alarm limits for more than one limit set by using theSelect Limit Set drop-down list box to select a new set and then select the EnableLimits check box again.

Defining an illegal heading sectorYou can define an illegal heading sector. If the vessel heading enters this sector, and thelimits are enabled, an alarm message is issued, for example:

Inside illegal riser sector turn port 170.2 170.0

An instruction to turn either to port or to starboard is included in the message, dependingon the direction in which the vessel heading entered the illegal sector.

When these limits are enabled, the illegal heading sector is displayed on the Posplotview (see Figure 17).

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Sector Center

Enter a compass direction, defining the center of the illegal heading sector.Sector Half Angle

Enter the half angle of the illegal heading sector.Enable Limits

Select this check box to enable the illegal heading sector limits. Ensure that thevessel heading is outside the illegal heading sector before enabling the limits(otherwise it will not be possible to indicate the required turn direction in themessage).

Enabling output signal to external alarm for position limitsExternal Alarm

Select this check box to enable the output signal to an external alarm in the eventof the position deviation limits being exceeded.

Note

The availability of an output signal to an external alarm is dependent onconfiguration.

Having RMS alarms issued through the K-Pos systemEnable RMS Alarms

Select this check box to have messages from the Riser Management System (RMS)issued in the K-Pos Message Line and Event List window. RMS alarm messagesare accompanied by audible signals in the same way as K-Pos alarms.

Selecting drilling display optionsThe Drilling Display Options dialog box allows you to select items for display on thePosplot view.

Select Drilling→Display Options. The Drilling Display Options dialog box is displayed.

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Figure 11 Drilling Display Options dialog box

Show Zero-Angle Position

For each riser sensor, the vessel position that will bring the Riser Angle to zero,and/or the vessel position that will bring the Riser Diff. Angle to zero, can beselected for display. The Name Tag appears on the Posplot view next to the positionmarker.

BOP/Stack

Select Show BOP Symbol to display the BOP symbol on the Posplot view.

Saving and reading RAM settingsThe settings for the Riser Angle Monitoring function are stored in an internal systemconfiguration file. Each dialog box on the Drilling menu (except the Sensors List dialogbox) provides Save and Read buttons. Using these buttons, you can save (only on localhard disk) and restore all the information that you have entered on all the pages of thisdialog box, such as bias values, manual values and limits.

To save the latest settings, click the Save button (previously saved settings areoverwritten, and are therefore no longer available).

To restore information entered in a dialog box, click the Read button. The saved settingsappear in the dialog box.

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Using the Position Advisory functionThe purpose of the Position Advisory function is to use the riser angle measurements tocalculate the vessel position that will bring the riser difference angle to zero.

The Position Advisory function provides the following information:• One position for each interfaced and enabled angle sensor set.• A composite position which is calculated using the average of the accepted sensors

selected for composite zero-angle-position calculation.When running the Position Advisory function:• You can select individual riser sensors for inclusion in composite angle calculations.• Individual position advisory calculations will ALWAYS be performed for enabled

riser sensors with OK status, independent of whether the position advisory symbolis presented. Calculations are performed both for absolute riser angle and for riserdifference angle.

• Composite advisory calculations will ALWAYS be performed if one ore more activeand selected riser sensors are available, independent of whether the individual positionadvisory symbols are presented.

Enabling the Position Advisory function1 Ensure that the required RAM sensors are enabled. To use saved RAM sensor

settings, click the Read button on the Drilling Sensors dialog box (see Figure 3).2 In the Drilling Configuration dialog box (see Figure 6):

a Select the sensors to be used in the composite angle calculations.b Enter a suitable Noise Filter.c Click the OK or Apply button.

3 In the Drilling Display Options dialog box (see Figure 11), select the Riser Angleand/or Riser Diff. Angle check boxes for the required individual sensors.• The individual sensor symbols for the enabled sensors are displayed on the

Posplot, Driller and Riser views.The sensor values can be monitored in the Riser Angle Monitoring - Sensor Listdialog box (see Figure 15).

4 In the Drilling Display Options dialog box, select the LRJ Angle (Riser Angle and/orRiser Diff. Angle) symbols for display.

5 If Position Advisory symbols for the selected riser sensors are not displayed inthe Posplot view, proceed as follows:a Place the cursor somewhere in the Posplot view and click the right trackball

button.• A shortcut menu is displayed.

b Select View Control.• The Posplot view control dialog box is displayed (see Figure 12).

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Figure 12 Example - Selection of RAM on the Show page of the Posplotview control dialog box

c Ensure that the RAM check box is selected on the Show page.d If the Position Advisory symbols for the selected riser sensors are still not

displayed on the Posplot view, try to change the display range up or down.e If the symbols are still not displayed, check the sensor values and possible

RAM messages.

Indication of advised positions on the Posplot viewThe advised positions, both for individual sensor positions and for composite position,are shown in the Posplot view (see Figure 13).

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Figure 13 Example - Posplot view showing position advisory symbols

+BLUE Advised position for Riser ERA Blue.LRJ ÄÄÄ Advised composite position for enabled sensors selected for

inclusion in composite angle calculation.BoP BOP position indicated by the center of the “o”.

The tags for position advisory symbols based on absolute riserangles are suffixed by .abs.

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The tags for position advisory symbols based on riser differenceangles are suffixed by .diff.

Note

The Position Advisory symbol tags are configurable, and maytherefore vary from system to system.

Using the Emergency Joystick Advisory (EJA)functionThe purpose of the Emergency Joystick Advisory (EJA) function is to give a graphicalindication on the Posplot view of the direction in which manual thrust must be appliedto move the vessel towards the advised position calculated by the Position Advisoryfunction (zero angle difference between BOP and riser).

The indication of required thrust direction is given by a red-filled arrow from the currentvessel reference point in a vessel-relative Posplot view (see Figure 14).

The conditions for activating the Emergency Joystick Advisory function are stated inConditions for displaying the EJA arrows on page 29.

Once activated, the EJA arrow will remain displayed until the stated conditions are nolonger satisfied and the Posplot view is reselected.

Together with the EJA arrow, a similar non-filled arrow is displayed (see Figure 14).This arrow indicates the direction of the obtained thrust.

Note

The size of the arrows does not indicate the magnitude of required and obtained thrust.

Conditions for displaying the EJA arrowsThe relative Posplot view with the EJA arrow is automatically presented in the workingarea of the display on the Operator Station which is currently in command when all thefollowing conditions are satisfied:• In position dropout Auto Position mode or in Joystick mode.• Valid riser angle measurements are available.• Zero-difference-angle calculations are presented (i.e. the Riser Difference Angle check

box for composite angles is selected).

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• The vessel is outside the warning position limit with respect to the calculatedComposite Advisory position, which is based on riser difference angle measurements.You should be aware that the displayed position limit circles are centred around theposition setpoint, which is not necessarily the same as the Composite Advisoryposition.

Preparations for running the EJA function1 In the Drilling Configuration dialog box (see Figure 9), select Enable EJA Function.2 Click the OK or Apply button.3 If the EJA arrows are not displayed in the Posplot view, but the conditions stated

in Conditions for displaying the EJA arrows on page 29 are satisfied, proceed asfollows:a Place the cursor somewhere in the Posplot view and click the right trackball


b Select View Control.• The Posplot view control dialog box is displayed (see Figure 12).

c Ensure that the RAM check box is selected on the Show page.

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Indication of the EJA arrow on the Posplot view

Figure 14 Example - Posplot view with the EJA function activated

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Displayed Riser Angleinformation

This section contains the following topics:Drilling Sensors dialog box .............................................................................................32Riser Angle Monitoring - Sensor List dialog box............................................................32Sensors dialog box - Tensioner page ...............................................................................34Posplot view.....................................................................................................................35Riser view ........................................................................................................................37Driller view ......................................................................................................................43RMS Summary view........................................................................................................51

Drilling Sensors dialog boxThis dialog box presents biased sensor readings for each individual riser and BOP sensor,either as X and Y inclination or as angle and bearing measurements. See Enablingand calibrating RAM sensors on page 14.

Riser Angle Monitoring - Sensor List dialogboxSelect Drilling→Sensor List. The Riser Angle Monitoring - Sensor List dialog box isdisplayed (see Figure 15).

This dialog box provides a summary of the sensor configuration, sensor measurementsand calculated zero angle positions for all individual riser and BOP sensors, and alsotheir respective composite results.

For each enabled and accepted riser sensor, two different surge/sway offset values maybe presented. These values indicate how much the vessel has to move in the surge andsway directions to obtain zero riser angle or zero riser difference angle with respect tothe riser sensors angle reference (a BOP sensor or the BOP manual configuration).

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Displayed Riser Angle information

All the sensor measurements are presented as Angle and Bearing (irrespective of the typeof measurements) so that they can easily be compared.

Figure 15 Example Riser Angle Monitoring - Sensor List dialog box

Sensor

Sensor name. The riser sensors are listed first, followed by the BOP sensors.Calculated values for riser and BOP composite zero riser angles are also included.

Absolute

Angle

The measured absolute riser or BOP angle in the direction of Bearing.Bearing

The bearing of the riser or BOP Angle (described above), relative to North.Surge Sway

The distance that the vessel would have to move in the surge and sway directionsto reach the position where the absolute riser angle would be zero.

Angle Reference

The angle reference for this riser sensor.Difference

Angle

The calculated riser difference angle in the direction of Bearing. (For riserdifference sensors, this is the measured riser difference angle.)Bearing

The bearing of the riser difference Angle, relative to North.Surge Sway

The distance that the vessel would have to move in the surge and sway directionsto reach the position where the riser difference angle would be zero.

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Sensors dialog box - Tensioner pageOpen the Sensors dialog box by selecting Sensors→Gyro and then click Tensioner. TheTensioner page is displayed (see Figure 16).

Figure 16 Example Sensors dialog box - Tensioner page

In this dialog box, you can enable the tensioner stroke sensors, set and enable upper andlower sensor limits, and monitor tensioner stroke sensor values and status.

A maximum of eight tensioner stroke sensor readings are shown both graphically(bar-graphs) and numerically on the Riser view. The upper and lower limits are alsoshown on the bar-graphs (see Riser view Riser view on page 37, Figure 18).Sensor

Shows the name or number of the tensioner stroke sensor.OK

Shows the tensioner stroke sensor status.Enable

Select this check box to enable a tensioner stroke sensor.Value

Shows the tensioner stroke sensor reading.

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Limits

You can specify the common Upper and Lower tensioner limits. Select Enable toactivate the limits.

Posplot viewThe Posplot view shows the BOP position at the manually-configured BOP positioncoordinates, the calculated zero angle positions for each individual riser sensor and alsofor the composite riser positions. Measured and filtered riser angles are used directly. Theillegal heading sector is also shown. Refer to the Display views chapter in the relevantmain K-Pos (OS) Operator Manual for a description of how to select display views.To make these RAM features visible on the Posplot view, you must select them fordisplay using the Drilling Display Options dialog box, and ensure that RAM is selected onthe Posplot view control dialog box Show page. Refer to the Posplot view section in therelevant main K-Pos (OS) Operator Manual for a description of this dialog box.

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Figure 17 Example Posplot view. The area in the upper-right corner (20 to 60 degrees)indicates the illegal heading sector.

Displayed positionsBOP The BOP position as entered in theWell Data dialog box.+RED.diff The calculated position where the riser difference angle as

measured by the Riser ERA Red sensor would be zero.+RED.abs The calculated position where the absolute riser angle as

measured by the Riser ERA Red sensor would be zero.

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LRJ.diff The calculated position where the composite lower riserdifference angle as measured by the riser sensors would be zero.The symbol indicating this position is called the CompositePosition Advisory symbol.

LRJ.abs The calculated position where the composite lower riser absoluteangle as measured by the riser sensors would be zero.

Illegal heading sectorThe illegal heading sector, defined using the Limits page of the Riser Angle Monitoringdialog box, is displayed as shown in the example in Figure 17. In this example, the vesselheading is outside the illegal sector (20 to 60 degrees).

Riser viewThe Riser view shows a range of graphical and numerical information for the riser andBOP angles, the riser difference angles and the configured riser difference angle limitsfor the currently selected limit set.If more than one limit set is configured in your system (for example Upper Flexjoint andLower Flexjoint), the Riser view control dialog box allows you to select which limit set isto be presented in the view (see Figure 22).The Riser view also provides you with a numeric and graphical presentation of thetensioner stroke sensor values.Refer to the Display views chapter in the relevant K-Pos (OS) Operator Manual for adescription of how to select display views.

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Figure 18 Example Riser view

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Sensor inclination measurements (angle andbearing) for riser, stack/BOP (reference) anddifference between riser and reference with:• Riser angle symbol as a solid circle line• Riser reference angle as a dotted circle

line• Riser difference angle as a solid filled

circleEach sensor is shown with a distinct colour.

Vessel symbol.

A maximum of four riser difference anglelimit circles for the selected limit set.

Circular (angle) and radial (bearing) grids.

Vessel reference point always in center.

Plot orientation either true (north up) orrelative (heading up).Display range value and decrease/increasebuttons. The range is the distance fromcenter to edge of plot in degrees or radians asdefined by the selected Angle display unit.The ÚÚÚ button decreases the displayed range.The ÙÙÙ button increases the displayed range.The distance between circular grid lines indegrees or radians.Riser angle, riser reference angle ordifference angle (and bearing) for eachenabled sensor.

The angle that is presented numerically isselected on the Sensors page on the Riserview control dialog box (see Figure 23).

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Riser difference angle limit values shownnumerically in degrees or radians for theselected limit set.

The riser difference angle limit values forthe available limit sets are defined andenabled on the Drilling Alarm Settings dialogbox (see Figure 10).

Bar-graphs showing tensioner stroke sensorreadings and upper/lower limits.

Numeric indications of tensioner strokesensor readings.

View controlsTo display the Riser view control dialog box:1 Place the cursor anywhere in the Riser view and click the right trackball button.

• A shortcut menu is displayed.2 Click View Control on this menu.

• The Riser view control dialog box is displayed.3 Click the required tab.

Mode

Figure 19 Riser view control dialog box - Mode page

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True

True plot orientation (north up).Relative

Relative plot orientation (heading up).

Grid

Figure 20 Riser view control dialog box - Grid page

Circular Grid

You can select to show or hide the circular grid (Show check box) and specify thespacing of the grid (Spacing drop-down list box).

Radial Grid

You can select to show or hide the radial grid (Show check box) and specify thespacing of the grid (Spacing drop-down list box).

Range

Figure 21 Riser view control dialog box - Range page

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Enter

Allows you to enter the range from center to edge of the plot. Click Apply to usethe new range setting.

Increase Range

Increases the displayed range. This button has the same function as the ÙÙÙ buttonin the upper right corner of the view.

Decrease Range

Decreases the displayed range. This button has the same function as the button ÚÚÚin the upper right corner of the view.

Limits

Figure 22 Riser view control dialog box - Limits page

Riser Difference

The Select Limit Set drop-down list box allows you to select Angle Limits whichpredefined set of riser angle difference limits to use for showing limit circles. TheShow check boxes allow you to select which of the riser difference angle limitcircles to show or hide on the plot. The numerical values for the selected limit setare shown on the view irrespective of your selection in the Show check boxes. Alimit is either a warning or an alarm. You can set and enable the values for the riserdifference angle limit sets on the Drilling Alarm Settings dialog box (see Figure 10).If you have set the limit values, but not enabled them, only the numerical valueswill be shown on the plot for the selected limit set. The limits for a selected limitset must be enabled in order to be shown graphically on the plot.

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Sensors

Figure 23 Riser view control dialog box - Sensors page

Show Symbol

Allows you to select which inclination symbol for each of the riser sensors is to bedisplayed on the plot.• The riser angle symbol is shown as a solid circle line.• The riser reference angle (i.e. the BOP angle) is shown as a dotted circle line.• The riser difference angle is shown as a solid filled circle.The symbols are colour-coded for each sensor.

Present Numeric

Allows you to select which data (riser angle, riser reference angle or riser differenceangle) is to be presented numerically on the right side of the view.

Driller viewThe Driller view (see Figure 24) combines information (both numerical and graphical)from both the Posplot view and the Riser view in one graphic presentation.

The vessel, setpoint, carrot, wind, current and BOP symbols are presented exactly as onthe Posplot view. You can, however, also select BOP as the plot center-point (in additionto vessel and setpoint). See Figure 25 for more information.

From the Riser view, the riser angle, riser reference angle (BOP angle) and riserdifference angle symbols and also the angle limits and the radial grid are included.

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Figure 24 Example Driller view

The riser angle is represented with a sensor symbol that is positioned relative to thecenter-point. The distance from the center-point is equal to the riser height multipliedwith the tangent to the angle, where angle can be the riser angle, the reference angle(BOP angle) or the riser difference angle. The vector from the symbol (for riser or riserdifference) towards the center-point shows the direction to move the vessel, and thedistance shows how far to move the vessel in order to reduce the angle to zero.

If more than one limit set is configured in your system (for example Upper Flexjoint andLower Flexjoint), the Driller view control dialog box allows you to select which limit setto be presented in the view (see Figure 28).

Refer to the Display views chapter in the relevant K-Pos (OS) Operator Manual for adescription of how to select display views.

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Symbols for the sensor inclinationmeasurements (angle and bearing) forriser, stack/BOP (reference) and differencebetween riser and reference with:• Riser angle symbol as a solid circle line• Riser reference angle as a dotted circle

line• Riser difference angle as a solid filled

circleEach sensor is shown with a distinct colour.

Vessel symbol.

A maximum of four riser difference anglelimit circles for the selected limit set. Thedisplay of the limit circles and limit set isselected on the Limits page on the Drillerview control dialog box. The riser differenceangle limit values (either warnings oralarms) for the selected limit set are definedon the Drilling Alarm Settings dialog box(see Figure 10). The limit circles arecolour-coded solid lines. The name of theselected limit set is displayed in the lowerright corner of the view.Circular (angle) and radial (bearing) grids.

The plot orientation may either be true(north up) or relative vessel (heading up),and the center-point of the plot can be eitherthe position of the vessel center-point, theposition setpoint or the BOP.

Vessel center-point shown as a very smallcircle.

Position setpoint shown as a crosssuperimposed on a circle.

BOP symbol shown as the letters BoP.

Carrot, wind and current symbols.Display range value and zoom buttons. Therange is the distance from center to edge ofplot in meters. The ÚÚÚ button decreases thedisplayed range. The ÙÙÙ button increases thedisplayed range.

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The distance between circular grid lines inmeters.

Text showing which predefined set of riserangle limits is used for showing the limitcircles.Numerical presentation of speed anddirection for wind and sea current. Fordetails on sea current presentation see thePosplot view chapter in the relevant K-Pos(OS) Operator Manual.Numerical presentation (in degrees orradians) of riser angle, riser reference angle(BOP angle) or riser difference angle (andbearing) for two sensors (preconfigured).

The angle that is presented numerically isselected on the Sensors page on the Drillerview control dialog box.

View controlsTo display the Driller view control dialog box:1 Place the cursor anywhere in the Driller view and click the right trackball button.

• A shortcut menu is displayed.2 Click View Control on this menu.

• The Driller view control dialog box is displayed.3 Click the required tab.

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Mode

Figure 25 Driller view control dialog box - Mode page

Relative, Vessel

Relative plot orientation (heading up), with the position of the vessel ascenter-point.

Relative, Relative

Relative plot orientation (heading up), with the position of the Position Setpointposition setpoint as center-point.

Relative, BOP

Relative plot orientation (heading up), with the position of the BOP as center-point.True, Vessel

True plot orientation (north up), with the position of the vessel as center-point.True, Position Setpoint

True plot orientation (north up), with the position of the position setpoint ascenter-point.

True, BOP

BOP True plot orientation (north up), with the position of the BOP as center-point.

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Grid

Figure 26 Driller view control dialog box - Grid page

Circular Grid


Radial Grid


Type

Allows you to select how to display the circular grid. You have three alternatives:• Square, Fixed to Earth

• Square, Fixed to Screen

• Circular, Fixed to Screen

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Range

Figure 27 Driller view control dialog box - Range page

Enter

Allows you to enter the Distance from Center ...to Edge of the Plot. Click the Applybutton to use the new range setting.

Increase Range

Increases the displayed range. This button has the same function as thecorresponding ÙÙÙ button in the upper right corner of the view.

Decrease Range

Decreases the displayed range. This button has the same function as thecorresponding ÚÚÚ button in the upper right corner of the view.

Limits

Figure 28 Driller view control dialog box - Limits page

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Riser Difference

The Select Limit Set drop-down list box allows you to select Angle Limits whichpredefined set of riser angle difference limits to use for showing limit circles. TheShow check boxes allow you to select which riser difference angle limit circles toshow or hide on the plot. The name of the shown limit set is displayed in the lowerright corner of the view. A limit is either a warning or an alarm. You can set andenable the values for the riser difference angle limit sets on the Drilling AlarmSettings dialog box (see Figure 10). If you have set the limit values, but not enabledthem, only the name of the selected limit set will be shown on the plot. The limitsfor a selected limit set must be enabled in order to be shown graphically on the plot.

Sensors

Figure 29 Driller view control dialog box - Sensors page

Show Symbol

Allows you to select which inclination symbol for each of the riser sensors is to bedisplayed on the plot.• The riser angle symbol is shown as a solid circle line.• The riser reference angle (BOP angle) is shown as a dotted circle line.• The riser difference angle is shown as a solid filled circle. The symbols are

colour-coded for each sensor.Present Numeric

Allows you to select which data (riser angle, riser reference angle or riser differenceangle) is to be presented numerically on the right side of the view.

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Show

Figure 30 Driller view control dialog box - Show page

Show/Hide

Allows you to individually select to show or hide the symbols for (position)Setpoint, Carrot,Wind/Current and RAM (stack/BOP) on the plot.

RMS Summary viewThe RMS summary view (see Figure 31) displays information provided by the RiserManagement System.

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Figure 31 Example RMS Summary view

Display range value and zoom buttons. Therange is the distance from center to edge ofplot in degrees or radians as defined by theselected Angle display unit.

The ÚÚÚ button decreases the displayed range.The ÙÙÙ button increases the displayed range.

The distance between circular grid lines indegrees or radians.

The distance between radial grid lines indegrees or radians

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his is the present RMS operational status,either Drilling, Non Drilling I, Non Drilling IIor Disconnected. If the RMS is unavailable,the text “Not available” is displayed. TheRMS operational status determines thecriteria used for the repositioning advise.This displays the time available for theoperator to initiate the emergency disconnectsequence in case of drift-off caused byblackout (Black Out) or a worst-singlefailure (WSF).

The fields are cleared if no data is available,or if the age of the information exceeds atime-out limit.This is the distance from the presentvessel position to the position currentlyrecommended by the RMS. Positive valuesare in the north and east directions, andnegative values are in the south and westdirections, respectively.

This describes the reliability of the datadisplayed:

Good

All sensors are available and used by theRMS.

Degraded

Some measurements are unavailable, and/or,for some data, manually entered values areused.

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These are the flexjoint angle plots for upper(left diagram) and lower (right diagram)flexjoint.

The north direction is displayed as a red line.

The present vessel position and heading isdisplayed by means of a vessel symbol.

The present flexjoint angle is displayed asa green dot.

The flexjoint angle warning and alarm limitsare displayed as a yellow and a red circle,respectively.

Circular (angle) and radial (bearing) grids.

Vessel reference point always in center.

Plot orientation either true (north up) orrelative (heading up).The most recent (Instant) measured orcalculated top tension, displayed as a greenbar graph and as a numerical value.

The Filtered top tension, displayed as aviolet bar-graph and as a numerical value.

Dynamic Tension Limit (DTL), inaccordance with API RP 16Q, used by theRMS as “High tension” alarm limit (red).

90 % DTL, used as “High tension” warninglimit (yellow).

Tmin, minimum recommended tension inaccordance with API RP Q16, used as “Lowtension” warning limit (yellow).

Tsrmin, minimum tension to avoid bucklingin accordance with API RP 16Q, used as“Low tension” alarm limit (red).

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The most recent (Instant) measured upperflexjoint (Slipjoint) stroke, displayed as agreen bar-graph and as a numerical value.

The Filtered upper flexjoint (Slipjoint)stroke, displayed as a violet bar-graph andas a numerical value.

The following limits are displayed:

Tensioner limit

The upper flexjoint strokes that correspondwith maximum (lower limit), and minimum(upper limit) tensioner stroke-outs.

Slipjoint limits

The maximum slipjoint stroke-out, and theminimum slipjoint stroke-in, respectively.A warning message is issued by the RMSif the filtered stroke plus/minus three timesthe stroke standard deviation exceeds anyof the limits.

An alarm message is issued by the RMSif the filtered stroke plus/minus twice thestroke standard deviation exceeds any of thelimits.

A yellow marker indicates the filtered strokeplus/minus three times the stroke standarddeviation.

A red marker indicates the filtered strokeplus/minus twice the stroke standarddeviation.

View ControlsTo display the RMS Summary view control dialog box:1 Place the cursor anywhere in the RMS Summary view and click the right trackball


2 Click View Control on this menu.• The RMS Summary view control dialog box is displayed.

3 Click the required tab.

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Mode

Figure 32 RMS Summary view control dialog box - Mode page

True

True plot orientation (north up).Relative

Relative plot orientation (heading up).

Grid

Figure 33 RMS Summary view control dialog box - Grid page

Circular Grid


Radial Grid


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Range

Figure 34 RMS Summary control dialog box - Range page

Enter

Allows you to enter the range from center to edge of the plot. Click Apply to usethe new range setting.

Increase Range

Increases the displayed range. This button has the same function as the ÙÙÙ buttonin the upper right corner of the view.

Decrease Range

Decreases the displayed range. This button has the same function as the button ÚÚÚin the upper right corner of the view.

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System messages

This section contains the following topics:RAM system messages ....................................................................................................58RMS messages .................................................................................................................59

RAM system messagesRefer to the The Message System chapter in the main K-Pos (OS) Operator Manual formore basic information regarding system messages.

Riser difference angle limit violationA message is reported if a riser difference angle violates one of the configured anglelimits (see Figure 10 and accompanying text). The message identifies the sensor name.The difference angle and the exceeded limit(s) are given as additional information.

Message example:

Riser angle out of limits riser yellow

This message is classified as “alarm”.

Illegal heading sector limit violationA message is reported if the vessel heading violates the limits of the illegal headingsector (see Posplot view on page 35 for a definition of illegal heading sector). Themessage indicates which way the vessel should turn to leave the illegal sector from thesame side as it entered the sector. The additional information to the message also givesthe vessel heading and the exceeded heading sector limit.

Message example:

Inside illegal riser sector Turn port

This message is classified as “alarm”.

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System messages

Caution

It is important to note that for this alarm message to report turn directioncorrectly, you must have enabled the sector limits when the vessel wasoutside the illegal heading sector. If not, no turn direction will be indicatedin this message.

Sensor measurement errorA message is reported when the IO status of one of the enabled riser/reference (BOP)sensors is not OK. The message identifies the sensor type and name.

Message examples:

Riser yellow read error

or

BOP yellow read error

These messages are classified as “warning”.

RMS messagesOn vessels equipped with a Riser Management System (RMS), messages from the RMScan be reported through the K-Pos system. RMS messages are issued in the Event List(and Message Line) on the K-Pos display screen if Enable RMS Alarms is selected in theDrilling Alarm Settings dialog box.

RMS UFJ out of limitsThis message is reported if upper or lower flexjoint angle is outside the warning oralarm limits.

This message is classified as “warning” (if the warning limit is exceeded) or “alarm”(if the alarm limit is exceeded).

RMS stroke out of lower limitsThis message is reported if the tensioner stroke is outside the warning or alarm limits.


RMS top tension out of lower limitsThis message is reported if the top tension is outside the warning or alarm limits.


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Simulator and Trainer

This section contains the following topics:Special simulator and trainer features..............................................................................60

Special simulator and trainer features

Sensor biasingWhen you run the system using the simulator or trainer, the angle measurements aresimulated based on the following assumptions:• The riser is a straight line from the BOP to the upper flexjoint.• The unbiased simulated riser sensor measurements reflect the physical situation,

i.e. the computed riser angle, based on the vessel reference point, the BOP positionand the riser height.

• The unbiased simulated reference (BOP) sensor measurements reflect the physicalsituation, i.e. the manually configured BOP inclination.

Based on these assumptions, the simulated values will reflect an ideal physical situationwithout the need for sensor biasing.

To make it possible to simulate the effects of bias adjustments, the RAM module makesuse of two different sets of sensor bias values, one for simulation and one for operation.Only the operational set is saved in the RAM configuration file when you click the Savebutton on the Riser Angle Monitoring dialog box. The simulation set will always be zeroat system start-up (also refer to Saving and reading RAM settings on page 25).

Vessel relative position of the upper flexjointAnother aspect you must take into consideration when running the system usingsimulator or trainer, is the vessel relative position of the upper flexjoint. (For anoperational system, this position is not relevant because all riser angles are measured.)You then need to know the relative position difference between the upper and lowerflexjoints, and the riser height.

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Simulator and Trainer

In most cases, the rotation center you select will coincide with the upper flexjoint. Butduring simulation there is nothing stopping you from changing rotation center. Whendoing so, this should not affect the simulated riser angle, because it does not representa change in the physical situation. Therefore, you need to be able to select the vesselrelative position of the upper flexjoint (for simulation) independently from the rotationcenter you have selected. Refer to the K-Pos Built-in Simulator Operator Manual formore information.

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K-POS Riser Angle Monitoring

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