Improving Control

Evolving SCADA architecture and applications in the oil and gas sector

 The supervisory control and data acquisition (SCADA) system is one of the most powerful tools for monitoring equipment and processing data in real time. These control systems provide a stable and cost-effective so­lu­tion for meeting the needs of the gas sector. SCADA includes a highly configurable set of industrial software applications that can be used for the management of almost any form of process production. The system is widely ap­p­lied in the upstream, midstream and downstream oil and gas sectors.

The basic SCADA architecture consists of programmable logic controllers (PLCs) or re­mo­te terminal units (RTUs). PLCs and RTUs are microcomputers that communicate with fac­tory machines, human-machine interface software, sensors and end-devices, and then route the information from those objects to computers through SCADA software. The SCADA software processes, distributes and displays the data, helping operators and other employees an­alyse it and make important decisions.

Role in the upstream and downstream oil and gas sector

The principal role of a SCADA system in the upstream oil and gas sector is remote data tra­nsmission. It gathers crucial information from oil wells and sends it to the headquarters, whe­re it is analysed. The SCADA system helps prevent blowouts, verifies the safety of pumping and maintains the integrity of the well bore. The system also aids reservoir engineers in de­termining the quantity of oil and gas, especially during the first few minutes of production. Organisations use SCADA systems to track the oil flow throughout its journey, from the well site to downstream plants. Further, SCADA systems prepare downstream processes for the inflow of the product. The downstream oil and gas industry is responsible for receiving and re­fining crude oil at processing plants, and then processing it into liquefied petroleum gas, li­quefied natural gas, gasoline and diesel oil. Re­fineries often operate 24×7, and thus organisations need a software system that can manage and monitor the plant’s performance and output. A SCADA system helps in monitoring the plant, and detects and resolves leaks that may emerge during operations.

Application in the gas industry

A SCADA system can be deployed at compre­ss­ed natural gas (CNG) stations, city gas stations and industrial units. It can be used for online reconciliation of billed and actual consumption, monitoring losses at CNG stations, centralised monitoring of trends in load and performance, monitoring of upstream pressure for each CNG compressor and different gas flow parameters, and identification of pressure loss across the grid, among other facilities. Further, the collated data can be used to provide business analytics – a functionality embedded in the SCADA system. This also helps in controlling price changes and making revisions at each CNG station.

A SCADA system deployed in a city gas distribution (CGD) network would offer various fu­nc­tionalities, and ensure operational ease and process optimisation. It would allow operators to remotely monitor and control widely distributed assets and facilities such as sectionalising valves, CNG stations, the pipeline network and transmission stations, irrespective of their location. This wide range of applications has led to the widespread use of the technology. SCADA can help detect disruption in the flow of fluid or gas transmission systems to ensure continued operations. This is crucial as SCADA aids in detecting leakages with high accuracy and significantly reduces the time spent on manually finding the actual location of a leakage. It also helps determine the magnitude and possible effects of a leakage beforehand. This, in turn, helps in reducing leakages and minimi­sing their effects such as loss of energy, transmission lags, environmental disasters and human injuries.

In a SCADA system, all sectionalising val­ves are integrated. This enables it to monitor and control their on/off status from the central control centre. Moreover, the technology en­ab­les the monitoring of valves on a real-time ba­sis for pressure control and remote shut-off, besides being able to raise alarms in case of an unexpected disaster. A large quantum of operational data pertaining to pipeline pressure, flow rate, temperature, gas composition and equipment status is collated by a SCADA system on a real-time basis through sensors and other internet of things devices such as automatic meters. This data, collected on a per minute/per hour/daily basis, enables the operator to generate analytical reports. To this end, business analytics software is issued along with a SCADA system. With this, an analysis of diagnosis, predictive failure and asset failure can be generated. Apart from these use cases, an important feature of SCADA is its ability to integrate Google Maps. With this feature, various gas stations can be marked in different co­lours, along with the adjacent geographies, to provide a detailed view of the area.

Today, many systems are monitored using the infrastructure of the corporate local area/ wide area network. Wireless technologies are now being widely deployed for the purpose of monitoring. A SCADA system has been ins­talled and commissioned by Mahanagar Gas Limited (MGL) for the safe and efficient operation of the CGD network as well as pipeline facilities geographically spread across the city of Mumbai and its suburbs – Navi Mumbai, Taloja and Ambernath. The SCADA master control centre (MCC) was set up at the MGL CGS Mahape terminal, Navi Mumbai. It is manned round the clock by SCADA operation engine­ers. It operates on a 24 hours per day, 365 days per year schedule.

Many other CGD companies have installed SCADA technology and are using it extensively for their gas operations. Reliance Gas Trans­por­tation Infrastructure Limited, GAIL Limited, Adani Gas Limited, Gujarat State Petronet Limi­ted, Haryana City Gas Distribution Limited, In­dra­prastha Gas Limited, and Assam Gas Com­pany Limited are some of the key players that have deployed SCADA.

Remote monitoring centre

Indian Oil Corporation Limited (IOCL) has esta­b­lished a remote monitoring centre in Hydera­bad. The centre has been set up by BHEL-GE Gas Turbine Services, a joint venture of BHEL and General Electric. The facility will manage and analyse operational data from 27 gas turbines at eight IOCL refineries in India. These turbines are responsible for meeting the power demand of the refineries. This technology is referred to as proactive predictive analytics, and is based on automated anomaly detection. The use of remote sensing technology will help maintain IOCL’s superior quality.

The way forward

The industrial control systems market, of which SCADA is a key aspect, is anticipated to reach $181.6 billion by 2024. The SCADA system ar­chi­tecture is constantly evolving, the most re­ce­nt advancement being cloud-based SCADA systems with big data functionality. Going forward, continuous research and development in SCADA systems will pave the way for better hardware and software, thereby improving op­e­rational efficiency.

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