A n essential part of a drillingship is the main hydraulicsystem that controls the

boring feed with the boring tower hy-draulic cylinders and, at the sametime, compensates the effects ofwaves and sea-level change.

One drilling ship is equipped witha condition monitoring (CM) system,called CM-Expert, that is 228m long,42m wide and can drill down to adepth of 10,000m. The wave compen-sation system on the ship can com-pensate against waves of up to 7.6mwith full drilling power.

The positioning of the drillingship is controlled by “Dynamic Posi-

tioning” GPS-controlled software.The main hydraulic system has atotal oil volume of 90,000 litres, ofwhich 16,000 litres is in the pipingsystem and drilling tower cylinders.The cylinder stroke is 24m with anormal moving speed of 1.5m persecond and 2.5 m per second in fastaction when the 29 hydraulic pumpsgive a flow rate of up to 33,000 litresper minute.

Operating at sea requires uniquespecifications in the hydraulic sys-tem, especially from the point of viewof service and reliability. A stoppagein the drilling work because of a fail-ure in the hydraulic system could

cause enormous costs, so it is impor-tant that the CM system controls thehydraulic system parameters 24/7,365 days a year.

CM-Expert consists of 31 opticalparticle counters, 31 pressure trans-ducers, 26 flowmeters and four mul-tifunctional oil condition sensorswith the main function of the sys-tem being to monitor the conditionof the hydraulic pumps. The systemgives an alarm of pump failures, re-ports the operating time of pumpsand gives information about theoverall pump condition by compar-ing the current actual measured val-ues to the measured values of a new

A special fleet designed for oil prospecting and exploratory drilling iscontrolled by a unique system that keeps it calm in rough waters.

Condition Monitoring On The High Seas

BY ROBERTUS KOPPIES,HYDAC

OGIAustralia.com | November 2015 HartEnergy.com70

Technology

CM-Expert consists of 31 optical particlecounters, 31 pressure transducers, 26flowmeters and four multifunctional oilcondition sensors. (Source: HYDAC)

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pump, enabling advanced planningof condition-based and time-opti-mised maintenance.

Real-time monitoringBased on the real-time measuringdata and alarms from the hydraulicsystem, the system sends an auto-matic report of immediate serviceneeds to the service personnel, thuspreventing expensive damages andadditional failures and increasing theutilisation rate. Service and mainte-nance operations can be optimisedand the lifetime of components in ahydraulic system is increased.

The sensor data is collected in arouter in the hydraulic room for dataprocessing and transferred to themain unit, which is installed in anisolated marshalling cabinet. Themain unit consists of an industrialPC and condition-monitoring soft-ware to process and visualise themeasurement data. The user inter-face is a touchscreen panel installedon the main unit, which can be indi-vidually tailored to meet each cus-tomer’s needs.

The visualisation and naming ofthe pump groups is done accordingto customer specifications, andnames such as “spare pump”, “mainpump 1”, “main pump 2” and “servopump” are used in the user inter-face. The sensor values, alarm limitsand alarms are shown for eachpump group.

When the limit values have beenreached or exceeded, the system sendsan automatic message to the operatorinforming which sensor and in whichmeasuring location triggered thealarm. Furthermore, the alarm will

show up in “traffic lights” located inthe hydraulic room or service centre.The stored measuring curves andlimit values of each measuring pointcan be easily checked afterwards.Condition of the hydraulic system andnecessary service actions can be eas-ily and quickly defined based on themeasuring data and easy switching

between online data and history datahelps to compare the values.

Easy messagingThe user interface display can showthe actual measured values both innumerical and graphical forms, andthe alarm and message system allowsthe user to find, define and comparethe alarms and history data of eachsensor. The alarm log shows alwaysopen alarms and messages and, inaddition the colour coding, shows thecondition of each group, which helpsto find active alarms and messages.

All alarms are stored in the alarmlog and can be read at a later date.For example, following a shiftchange, the next shift can checkalarms, messages and commentsduring the previous shift.

A reliable condition monitoringsystem needs calibrated sensors, sothere is a calibration test bench in-stalled in each ship to ensure reliableand long sensor operation. A sup-plier’s specialised service technicianmaintains the system and calibratesall sensors once a year.

The CM-Expert condition moni-toring system can be installed tomost applications and sensors. n

November 2015 | OGIAustralia.com 71HartEnergy.com

Features of the CM-Expert• Constant monitoring of the production media;

• Automatic messaging of maintenance-relevant limitshave been reached;

• Immediate alarm when the limits are exceeded;

• Early detection of the faults and prevention of “emergencies”;

• Optimisation of service intervals;

• Reduction of maintenance and repair costs;

• Prevention of the operation downtime and consequential damage;

• Customer-tailored user-interface and operation.

A drilling ship is ideal object for the CM-Expert condition monitoring system.(Source: HYDAC)

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