CHAPTER - 22 ROLE OF INSTRUMENTATION ENGINEERS IN ONGC (AN OVERVIEW) It is often said that the proliferation of knowledge and the accelerating development of technology have rendered our environment so complex that no one can understand even a small portion of it. The statement would have been undoubtly correct except for the circumstance that new knowledge can be better organized and that automation can relieve us of a considerable number of chores, as a consequence of which activity can be concentrated on subjects having technological meaning. In this evolution, clear presentation of modern instruments is of great importance. As machines are being increasingly applied , not only to replace human muscle, but also to develop a good substitute for the routine functions of the of human brains, it becomes more and more important to have an up-to-date summary of technological aids as they become available. By now you must have been made aware of the multi disciplinary nature of activities in ONGC. Our company's core business is exploration and production of hydrocarbons. The journey from carrying out the seismic survey to the recovery of oil and gas to the ultimate process of stabilizing and marketing the recovered crude and natural gas, involves a multitude of different processes and deployment of various equipments. The processes involved are different and extremely complex and it is not humanly possible for manually carrying out all these activities. It would not be out of place to recall an well remembered event which occurred on the 9th of November 1965 , when 30 million people in the north eastern part of USA were left without electricity. The cause of the break down remained obscure for a period of five days. It should be understood that a mere application of complete application of the principles of automation to information gathering , systems engineering and the connected aspects of safety devices can lead to an rapid Understanding of the break down and avoidance avoidance of similar events in the future. The required skill of the operator demands a thorough understanding of the apparatus. The same understanding is needed if the malfunctions are to be avoided and in case they do occur, corrected. It is for these reasons that a company with varied functions needs a dedicated team of Instrumentation Engineers. Hence to carry out this mammoth task of keeping the various processes running smoothly, with minimum of down time of equipment, with maximum efficiency, with safety of man and material as prime importance and in an most cost effective manner ONGC possesses a battalion of qualified, highly experienced, dynamic Instrumentation Engineers. No system can remain healthy without the infusion of new blood, hence to keep the already vibrant group of engineers healthy, strong and dynamic, the policy of our company is to recruit fresh graduates engineers with new ideas, with upto-date knowledge of the latest technologies available in the world. As mentioned earlier, ONGC has various activities where the instrumentation engineers are deployed. The various avenues where instrumentation engineers would be deployed during the tenure in ONGC would be:-
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CATEGORY-I MAINTENANCE INSTRUMENTA SYSTMS ON OFFSHORE /ONSHORE DRILLING WORK OVER
CATEGORY-II MAINTENANCE OF INSTRUMENTATIO SYSTMS ON OFFSHORE /ONSHORE PRODUCTION INSTALLATIONS
CATEGORY-III MAINTENANCE INSTRUMENTATI SYSTMS ON GAS PROCESSING COMPLEX AT HAZIRA/URAN/ MINI
CATEGORY-IV R&D PROCESS INSTRUMENTAL ON DESIGN, ENGINEERING.PL ANNING & CONSTRUCTION .WORK SHOPINST. LAB
CATEGORY-V MANAGEMENT SERVICES, SHE. PROVISIONING. TECHNICAL SUPPORT, QA.
For a better understanding of the functions of the engineers in various categories a brief description of the job profile would not be out of place. CATEGQRY-I - MAINTENANCE OF INSTRUMENTATION SYSTMS DEPLOYED ON OFFSHORE /ONSHORE DRILLING RIGS/ WORK OVER RIGS ONGC drills exploratory and development wells all over India as well as a few international locations through a fleet of 75 land rigs and 10 offshore rigs . Well depths vary from a few hundred to a few thousand feet below the surface of the earth. Each rig is equipped with a array of instrumentation monitors which help the driller to drill a hole efficiently and safely. For a driller the drilling rig instrumentation system is like extended hands and eyes of the driller so as to reach where his hands cannot reach and see what his eyes cannot see. Drilling rigs are therefore very critical as it helps to monitor various drilling parameters for smooth , efficient and safe drilling operations. These systems are at present conventional hydro-electricalmechanical systems. Revamping and up gradation of these systems to state of art systems is in progress under Project PROMISE. All the ONGC owned rigs shall be linked to the enterprise wide SCADA system for proper monitoring, coordination and creating data archives for future analysis of the drilling data. A driller needs to monitor a set of drilling parameters so as to ensure drilling a smooth, straight and a safe hole in a most cost effective manner. One would come across the following instrumentation systems on a drilling rig:1.
Weight Indicator - indicates the weight on bit and the hook load, these parameters are essential to the driller for the efficient control of rate of penetration and hole direction. The hydraulic dead line anchor type is the standard of the industry. These systems accurately sense the tension in thedeadline and use this to indicate the weight on bit and hook load on an hydraulic indicator mounted in the drillers console.
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Tong line pull / Tong torque - this provides an accurate check on the critical make-up and break-out torque for all tool joints, drill collars and drill strings. This is a necessity for maximum drill string life.
Mud Volume Totalizer - commonly known as the MVT - this instrument is very critical as it monitors the level of drilling mud in all the mud tanks and any indication of Mud Gain or Mud Loss gives us an indication of an impending
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gas kick or a complex well complication. Corrective action can be taken to prevent eventualities like a blow out. The system also monitors the strokes / min. and cumulative strokes of the mud pumps which gives an ; indirect indication of the total volume of mud pumped into the hole. 4.
Return Mud Flow - commonly known as the MFC ( Mud Flow Console ) another important instrument installed on the Mud System of any drilling rig monitors the amount of mud returning from the hole.
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Strokes'Per Min - this is a parameter, which again gives an analog indication of the mud pump performance and an indirect indication of the total volume of mud pumped into the well.
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Mud Pump Pressure - a very high pressure monitoring system installed on the discharge line of the mud pumps.
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Rotary RPM - The RPM sensor is a magnetically activated probe mounted next to the rotary table or adjacent to any object which rotates at a speed proportion to the rotary table. The rotary speed indication helps the driller to select an optimum speed for faster penetration.
Rotary Torque - this provides a reliable and sensitive relative torque indication . a change in rotary torque experienced by the rotary table indicates stress on the drill pipe. This instrument warns a driller of the potential twist off, locked cones on the bit, bit trouble, and gives the driller an indication when to change bits.
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Rate of Penetration Mile indicator- the ton mile indicator receives signals from " tons" and "miles" sensors , automatically computes ton -miles and displays them on two resettable counters. This indication gives a clear indication of the work done by the wire rope and the precise time when the rope needs to be cut.An important parameter essential for safe and cost effective drilling practices.
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Mud Logging System - this system monitors all the drilling parameters along with trapped gas from the return mud at the shale shaker, analyzing the same for all the different hydrocarbon components from Cl to C9 and monitoring the presence of H2S gas, indicating the mud density and mud temperatures and finally providing these parameters to the well site geologists for further analysis and records.
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Drill Site Servers , Work stations and SCADA equipments. ( will be the integral part of the instrumentation systems after revamping and upgradation under Project PROMISE is completed.)
The instrumentation engineer shall have the responsibilities of maintaining the rig instrumentation systems so as to ensure availability of equipments on a 24 X 7 basis. They shall have to rig down the system prior to every rig move and rig up the same to 412
ensure availability of the system at the time of spudding a new location. Planning , procurement and provisioning of new systems and spares for carrying out the day to day operation and maintenance of the instrumentation system so as to ensure nil or minimum down time of the drilling equipment shall form part of the duties of the instrumentation engineers posted with the drilling services. CATEGORY-II - MAINTENANCE OF INSTRUMENTATION SYSTEMS DEPLOYED ON OFFSHORE / ONSHORE PRODUCTION INSTALLATIONS One of the core activities of ONGC is production and processing of hydrocarbons. In fulfilling the commitment to the nation your company has left no stone unturned in adopting and implementing the state of art technological marvels into the field of oil and gas production - all this to achieve the set targets of hydrocarbon production and fulfilling the dream of taking the nation towards self reliance in oil and natural gas. ONGC achieves its targets through on-land and offshore hydrocarbon installations spread over India along with its territorial waters. Presently we have nearly 170 on land processing facilities catering to crude and natural gas received from approximately 4500 wells. The major portion of the production is from our offshore wells. To cater to the hydrocarbon production from nearly 1001 off shore wells we have strength of 134 unmanned well platforms and nine processing platforms. Each of the production installations have an array of instrumentation systems with the technology ranging from conventional pneumatic systems to the state of art microprocessor based SMART field instruments supported by the best in the world Distributed Control Systems. With the initiatives of Project SCADA all the production installations both onshore and offshore have been linked to the enterprise wide SCADA system for the entire organization. The system architecture is a 3-tier architecture. The first tier SCADA system is at the processing installation stage like the GGS/ GCS / CTF / Process Platform level & monitors the parameters pertaining to the connected wells along with the local process parameters. All these I s' Tier SCADA systems has been integrated with the regional Asset SCADA MIS (called the 2 nd Tier SCADA system) so that the management at the Regional Asset Head Quarters can monitor the fields pertaining to their respective assets. The 3 rd Tier SCADA MIS has been implemented at the Corporate Head Quarters at Delhi, so that the corporate management gets the consolidated data of the total ONGC fields. The various systems that one would encounter in various Offshore and Onshore production installations are :Processing Platforms/GGS / GCS control normally achieved by single loop 1. Pressure pneumatic/electronic pressure controllers and control valves as final control elements. This is required for proper control of separator pressure so as to ensure efficient separation of the oil, water and gas components in the well produce. 2.
Level control normally achieved by single loop pneumatic/electronic level controllers and control valves as final control elements. This is required for proper control of oil level in the separators so as to provide proper retention time for efficient release of dissolved gas and water from the emulsified well produce. 413
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Quantity Of Oil Produced - The quantity of oil produced is measured with help of various types of flow measuring devices. The most common means of measurement is the Positive Displacement typemeters. Other meters that are being presently used are the Corriolis type Mass flow meters, turbine meters for low viscous fluids etc. The accuracy, installation practices and calibration procedures are carried out as per API standards.
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Quantity Of Gas Produced : The quantity of gas produced at an installation is normally been measured by Orifice, presently turbine meters are being used at a few installations.
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Safety Devices: Safety Release valves and Rupture Discs are normally used on Onland installations. In a few installations which have come up recently, a system of constant monitoring of the various safety related parameters like HI/LO pressure and levels in vessels, HI/LO pressures of gas and oil pipelines and introduction of Shut Down Logic , Annunciation of alarms, Emergency Shut Down etc has been incorporated.
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On offshore installations the total process is monitored and controlled through state of art Distributed Control Systems located centrally in the main control room. Programmable Logic Controllers control the safety logics of all the off shore installations. The DCS also receives data from all associated plants and equipments like the Gas Compressors, Gas Turbines , Water Makers , UPS, etc. A sophisticated Gas Monitoring System monitors the levels of hydrocarbon and H2S gas at all places where possibilities of gas leakage exists. On offshore production installations safety of man and material has been given prime importance during the design of these platforms. This has to be borne in mind by all working crew, with instrumentation engineers in particular, that any lapse in duties may bring a catastrophic end to a technological marvel called the Offshore Process Platform.
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Central Tank Farm The Central Tank Farm commonly called the CTF consists of an array of fixed and floating roof tanks where crude oil produced and processed at the GGS's is brought for storing and stabilizing before the same is pumped to the refineries. Level indicators of the simple Dip ,Rope And Float Type, Tape And Float Type and sophisticated Servo Level Gauges, Radar Gauges are used for monitoring the liquid levels in these tanks. In most of the places the difference in levels is the bases of Custody Transfer of oil to the various downstream oil companies. Plans of installing Ultrasonic Flow Meters as custody transfer metering for oil sold are in progress.
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Gas Metering Stations Gas produced and processed at the GCS's is supplied to various customers , presently a centralized organization GAIL. The amount of gas sold is measured by highly accurate systems of metering. The older installations have the Orifice -Differential Pressure Transmitters - Flow recorders as the metering system. The standards of installation, accuracy and calibration procedures are as per American Gas Association Report 3 and NX19. The newer metering stations have adopted the state of art metering systems like turbine meters, ultrasonic flow meters along with sophisticated flow computers incorporating the latest versions of AGA standards for flow computations taking into account the compensations due to variations of temperature , pressure, compressibility factor etc. Gas compressor stations and Oil pumping Stations Associated and low pressure gas produced at GGS's but in large volumes is compressed to high pressures to make it transportable to various consumers. Large gas compressors are installed to carry out this job. Instrumentation systems installed monitor the various parameters of the gas being processed and also monitors all the compressor parameters like inlet pressures, discharge pressures, lube oil pressure, vibration , temperature of various components of the rotating machine , associated alarms and trip logics generated through simple relay based logic or through use of Programmable Logic Controllers. Instrumentation engineers posted on these installations have the task of looking after these systems so as to ensure availability of production equipments on a 24X7 basis. Day to day maintenance, planning and implementing preventive and predictive maintenance schedules, carrying out scheduled calibration of all field and control room instruments, planning, scheduling and carrying out safety checks so as to ensure safety of man and material, planning of spares and systems to achieve the targets of minimum down time, maximum efficiency and low maintenance costs — these are a few of the job parameters of instrumentation engineers deployed on onshore / offshore production installations. CATEGORY-III - MAINTENANCE OF INSTRUMENTATION SYSTEMS DEPLOYED ON GAS PROCESSING COMPLEX AT HAZIRA / URAN / MINI REFINARY/ETC Apart from the business of exploring, processing and production of hydrocarbons ONGC operates a few processing complexes at Uran, Hazira, Gandhar, mini refinery at Rajamundry and the latest is the MRPL at Mangalore. At Hazira the complex called in short HGPC or Hazira Gas Processing Complex handles 41 MMM 3 of sour natural gas ahd along with it receives a huge amount of sour condensate. The main activities of the HGPC is sweetening of the gas , dehydration and dew point depressant before the gas is fed to the HBJ gas pipe line through custody transfer meters for onward transmission and distribution to various consumers by GAIL. Other value added products which have turned out to be the major contributors to the high profits of HGPC are LPG, Kerosene, NGL, Aromatic Naphtha (ARN), Heavy Cut and Sulphur. Another gem of installations with similar activities is the LPG plant at Uran. Here the total hydrocarbon production of Mumbai high oil & gas fields (except for south Basein ) is received here. The crude is stabilized before it is transported t various refineries through custody transfer metering systems. LPG along with other value added 415
products is produced at Uran. The very complex nature of the process calls for the most sophisticated instrumentation and process control systems. The fully automated plants are equipped with the state of art instrumentation system backed up with an array of latest Distributed Control Systems. The plants meet its power and steam requirements through captive power plant and steam generation systems. The very high standards of the equipment available at the complex and the efforts for over achieving of set annual targets call for an highly dynamic, dedicated and self motivated team of instrumentation engineers who shall have to maintain these system to its maximum operating efficiency. In short a tenure at HGPC, LPG plant Uran, Mini refinery at Rajamundry or any other petro - complex similar to these is a must for a smooth carrier growth of young engineers. CATEGORY-IV - R&D INSTITUTES, PROCESS INSTRUMENTATION DESIGN, ENGINEERING,PLANNING », CONSTRUCTION .WORK SHOP INST.LAB ONGC has institutionalized research and development in the oil & natural gas and related sectors and established separate institutes to undertake specific activities in key areas of exploration, drilling, reservoir management, production technology, ocean engineering, safety and environment protection in form of nine independently managed R&D centers. These centers are equipped with highly sophisticated set of analytical equipments pertaining to the relative field of research. An highly specialized field which calls for instrumentation engineers trained and made experts in the field of management, trouble shooting and carrying out repairs of these systems with minimum down time. Another area which requires the services of highly qualified, dedicated and experienced team of instrumentation engineers is the Design, Engineering, Planning and Construction wing of ONGC. : CATEGORY-V - MANAGEMENT SERVICES. SHE. ROVISIONING, TECHNICAL SUPPORT. QA. No engineering services can successfully complete its assignment until it has a full support of its provisioning and technical support group whose main task is to plan, coordinate and ensure that all technical support, by way of requisite spares and systems , are made available right on time so that the maintenance teams can carry out the repair and maintenance of the systems hence adhering to their maintenance schedules. A team of qualified instrumentation engineers with some amount of field exposure, a flare for drawing up specification and data sheets and vast exposure to the world market so as to update the vendor data base would be essential. Other support groups like the QAD, SHE and Management also need the services of qualified Instrumentation engineers for proper coordination, implementation and compliance of directives of various statutory bodies in their respective fields of activities around ONGC.
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