Communications in the Digital Oilfield

Oil and gas companies face daunting communications challenges, particularly when it comes to ever-increasing data requirements.

For decades, oil companies have attempted to rejig their entire value chain, harnessing technological advances in IT, communications and engineering.

The 1960s practice of manual logging of offshore operational data has evolved into digitisation of data and transmission via satellite. Now, those companies must embark on a sophisticated and ambitious program to integrate (and increasingly automate) every stage of company operations.

With the baseline cost of leasing a single deep water rig approaching US$600K each day, minimising project times alone can substantially bring down costs. Better communications and workflow automation can dramatically improve safety and avoid expensive disasters:

• In 1988, the Piper Alpha explosion on a North Sea production platform operated by Occidental Petroleum killed 167 workers and cost US$3.4 billion. Failure to communicate between work shifts had led to a gas leak through pipework that should have been closed with a safety seal. A safety workflow generated out of the knowledge of each shift’s work program could have corrected this oversight.
• In 2010, British Petroleum’s Deepwater Horizon blowout killed 11 workers on a Gulf of Mexico platform, caused an ongoing environmental (and PR) catastrophe and cost US$18.7 billion. Analysis of the disaster concluded that had the blowout protection on the wellhead been fitted with remote-controlled or acoustically triggered actuators, the well could have been cut off and disaster possibly avoided.

Lessons from these disasters tell us that automated and remote monitoring of production facilities and wellheads together with distributed control systems prove their worth. The communications investment that has brought extensive data on oil reservoirs has paid off over their lifetime, showing more accurately where resources should be deployed. Thus the Digital Oilfield (DOF) program has demonstrated in pilots and a few fields how to deliver more revenue and minimise non-productive time. However, the overall investment remains to be completed, industry-wide.

Evolving along with technology

Implementing the Digital Oilfield (also referred to as Smart Field, Intelligent Oil Field, or i-Field) began in the upstream Exploration and Production (E&P) sector. This is where costs and risks are highest, because prospecting is always something of a gamble.

DOF technology has evolved incrementally:

1. Prior to 1980, data from multiple wells and fields was digitised, collated and entered into spreadsheets, enabling basic but faster and more consistent production analyses for an entire field.
2. Adding instrumentation at wellheads, automatic data capture and feeding the results into SCADA systems compelled companies to upgrade their communications systems. This not only improved the quality and delivery of data, but also reduced the on-site staff overhead.
3. In the 1980s, the explosion of data generated by 3D seismic surveys demanded a further boost in communications capabilities.
4. Engineering and embedded system developments took advantage of improved communications, using digital control systems, where remotely actuated equipment controls surface operations over great distances.
5. As field equipment intelligence increased, so did the potential to fully automate operations. Permanent gauges and automatic flow controls for continuous remote monitoring and automatic interaction combine with extensive downhole communication so wells become mostly self-managing.
6. As ‘easy oil’ opportunities ran dry in the 1990s, companies pursued unconventional drilling operations (eg, horizontal drilling) in less accessible locations under sea and on land.
7. Since 2004, time lapse (4D) seismic surveys have generated petabytes of data that must be transmitted over very high bandwidth connections, then processed and stored, creating considerably more accurate and dynamic monitoring of oil reservoirs.

Although these new capabilities have undoubtedly added to the complexity of modern E&P operations, they offer huge benefits. With the possibility of real-time monitoring and control, vast quantities of data pouring in and with the big picture of the company’s assets, operations and market suddenly visible, it is possible to adjust business operations dynamically and interactively. As machine-to-machine communication improves, more and more of the physical plant and facilities will run completely automatically, adjusting and repairing itself as necessary.

Implementing a DOF

Communications — and data communications in particular — lie right at the heart of the DOF concept. While oil company communications design can become complicated very quickly, a basic starting point for the designer is to understand the data requirements of each operational unit. The overall communications architecture must then integrate each unit’s requirements with the technical options for supporting them, to form the company’s total communications system plan.

Although companies vary (since some companies are strictly midstream or strictly upstream), a generalised picture of a company that embraces all three sectors might include corporate centres, oilfields and refineries — including oil terminals (tank farms), port/rail facilities and pipeline systems.

From a communications perspective, onshore and offshore fields have a great deal in common — streams of sensor data from drilling and other equipment transmit to metering, processing and control stations:

• Surveillance, video and camera feeds.
• Staff communicate via voice and data, usually via radio.
• Field and seismic data continuously transmit to an onshore network operations centre (NOC).
• The onshore NOC remotely monitors and controls platform equipment.
• A broadband campus communications system for platform staff supports voice, PSTN access, internet, email, videoconferencing, IPTV, video surveillance and security.

Onshore fields

An onshore fields comprises a number of drilling rigs with instrumentation over each wellhead that includes sensors and triggered actuators for remote monitoring and control of valves, drill heads and other equipment. Each rig feeds data — often wirelessly through a remote terminal unit (RTU) or programmable automation controller (PAC) — into either:

• a metering station,
• supervisory control and data acquisition (SCADA) system, or
• a distributed control system (DCS).

This can automatically log sensor data when monitoring oil and gas levels from the well. Rigs are also connected to a control panel so that valves can be closed or opened manually or remotely.

The metering station transmits production data and alarm notifications through a fast (eg, fibre) connection to a process station which processes crude oil to remove gas, water, solids and other non-saleable components. IP video surveillance and instrumentation in the metering and process stations and pipelines can be transmitted to a central control room, which, in turn, connects to the production management centre.

Through this data path geologists can ‘see’ into the oilfield reservoir, and engineers can use portable devices (eg, laptops, tablets and even smartphones) to remotely monitor, perform diagnostics and control oilfield equipment. Integrating multiple DCSs extends control across multiple oilfields from a single point.

However, this degree of automation does not eliminate the need for personnel at the sites. During exploration, work crews will construct, maintain and move drilling sites. Drilling can be controlled remotely, but fixing faults generally requires human intervention.

A substantial proportion of E&P project costs is in non-productive time (measured in lost rig days) while drilling is halted by equipment failures, stuck pipes and loss of circulation. Crews working in dangerous environments must resolve drilling issues quickly, so communications are essential for a speedy problem resolution and for enhancing worker safety.

Sensor data from exploratory drilling and current video footage can be analysed by experts (who may be hundreds, even thousands, of kilometres away) to identify the cause of failure and to recommend a corrective course of action. The field office (or ‘forward operations office’) is the communications contact between the field network which generates and transports the data and the enterprise network which receives, stores and analyses field intelligence.

Field network workers typically use intrinsically safe (C1D2) portable radios for voice communications. More powerful vehicular radios and vehicle area networks (VANETs) add range, flexibility and mobility to the portable coverage, and can include cab-mounted IP cameras and better mobile data.

Digital radio usually supports location services and man-down safety features. Location tracking is critical in field operations, for locating personnel during emergencies and asset management, logistics, situating construction material, and establishing the position and status of monitored equipment. Technologies such as RFID can automate location tracking, streamlining workflows and improving situational awareness and safety.

Since oilfields tend to be in remote — even hostile — locations, robust and resilient communications act as a lifeline. Forward-operating campuses provide accommodation, security and communications for field staff. Data and communications that carry voice, PSTN access, internet, email, videoconferencing, IPTV, video surveillance and security systems must be set up from scratch.

Offshore fields

Land-based oilfields are difficult enough to operate and maintain, but offshore fields add a new level of complexity and cost. Conditions are often harsh and unforgiving — they may be far from land and operating in depths up to 2000 metres. (A deepwater mobile offshore drilling unit (MODU) — basically a submarine driller — can go to 3000 metres.)

The familiar image of an offshore platform is a self-contained man-made island, fixed or tethered in deep water, with everything needed to drill, extract and process hydrocarbons, and store them until they can be transported to shore by undersea pipeline. Where pipelines are not viable, specialised floating storage and offloading (FSO) vessels provide storage and processing. Manned platforms are also offshore hotels, with accommodation, cafeteria, office, medical and recreational facilities for personnel who will live there for weeks at a time. Supply ships keep the platforms equipped and helicopters ferry staff to shore as required.

From a communications perspective, there are significant differences from the onshore oilfield. An offshore platform is far more cramped, exposed and dangerous than an onshore field. (Industry fatalities offshore far exceed those on land.) Space limitations impose physical constraints on workers’ movements, where equipment can be located, work processes and even on what equipment (communications or otherwise) can be accommodated.

Communication with supply ships and FSOs is critical for offshore platforms. To pass accurate production information, a three-way dialogue between platforms, FSOs and onshore facilities is essential. Even under the worst of conditions, contact with supply ships is vital for maintenance and for the safety and support of platform staff.

To transmit real-time field data onshore and to support remote monitoring and control of field equipment depends on a very fast, high-capacity link between platforms, and between platform and shore. The standard method has been to use VSAT (very small aperture terminal) satellite communications. However, real-time data acquisition, monitoring and control are not feasible via satellite, due to limited bandwidth, delay (latency) associated with transmitting to satellite and down to the destination, together with vulnerability to bad weather.

If the platforms are neither too far apart nor too distant from shore, submarine fibre-optic cable is an attractive alternative. It offers much higher bandwidth, low latencies (20 to 50 ms) and relative immunity from weather-related interference. If laying down fibre is not possible, then VSAT or microwave must be considered.

Refineries

Oil refining applies physical and chemical processes to crude oil to remove impurities (eg, salt, sulfur, mercaptans) and distils from it saleable products such as gasoline, diesel, kerosene, LPG and tar. Often, a refinery has tank farms for storing incoming crude and outgoing refined products near an oil terminal or port.

The refining process is extremely involved, highly polluting and extremely dangerous as steam, chemical additives (acids and strong alkalis), high temperatures and pressures create potentially explosive mixtures of liquid and gas.

Each aspect of refinery operations — bringing in crude, storing it, piping it into refining units, transporting refined products to storage and distribution — generates a constant stream of interlocking data production data, sensor data, equipment status, work plans, maintenance schedules and so on. Voice communications, usually over radio systems, keep refinery workers in touch.

To better manage this complexity, it makes sense to integrate communications with IT systems, thus automating processes and workflows as much as possible. Technologies such as RFID, intelligent sensors and programmable automation controllers have already removed some less responsive manual processes. Integrating these technologies more closely with workflows can reduce non-productive time, safety risks and environmental impact. At the same time, automated monitoring and control means that companies have a highly accurate picture of production, optimise refining operations, anticipate problems before they arise and vitally, improve safety.

Tying it all together

While on the face of it, the data communications requirements of oil and companies resemble the challenges other industries face, these are amplified by the scale of their global reach, complexity of operations and the immense commercial, human and environmental risk.

So for this industry, more than most, communications must be:

• totally reliable (must not lose service);
• resilient (must recover from failure quickly);
• robust (must work in harsh environments) and long lasting;
• secure (communications and data must be protected from loss, damage or intrusion);
• safe (may require intrinsic safety in some environments);
• integrated (must integrate many processes seamlessly).

A variety of communications technologies is available, including:

• VSAT satellite, a mainstay of oil and gas communications, has excellent coverage, is fast and relatively inexpensive to set up but has limited bandwidth and latency problems. VSAT options offering higher bandwidth are available, but may be prohibitively costly. In rough seas, communication with ships can be disrupted as they struggle to keep aligned with the satellite.
• Radio — the standard for voice communications — has excellent coverage, lower latency than VSAT, but takes time and resources to deploy and offers limited data bandwidth.
• WiMax and LTE can provide both data and voice communications with very low latency and high bandwidth, but coverage, which is more limited than radio, dynamically depends on bandwidth usage.

No single technology can adequately serve all the communications needs of an oil and gas company. Each has its strengths and weaknesses. But whichever technology (or technologies) is chosen, it must take into account the fact that the industry has already entered the era of big data where terabyte and petabyte volumes of data from numerous sources stream in daily. Faced with shrinking revenues and rising costs, the business value of using that data effectively is a matter of survival. Faster, more accurate decision-making is the key to making the oil and gas business work, and that depends on reliable communications.

This is an edited summary of two white papers issued by Tait Communications, used with permission. You can find them at go.taitradio.com/communicating-in-the-digital-oilfield-part-2.html.

Images courtesy Neil Kremer (CC BY-ND 2.0) and Lindsey G (CC-BY-2.0)