Virtualization technologies reduce risk, downtime
Virtualization technologies are simplifying offshore central control systems and enabling companies to reduce energy consumption and increase availability for critical applications.
Virtualization—and its advantages—is incredibly important in the oil and gas industry, as companies continue to look for ways to reduce risk and unplanned downtime, and to keep operations running at peak efficiency.
Simplifying virtualization technology
Virtualization allows users to emulate a computer, including its operating system and applications, so it can easily run on a host computer. A laptop or desktop PC can be converted into a virtual PC that can be copied and run on another host computer.
A virtual PC, or virtual machine (VM), is a file that contains everything to boot and run the applications. In essence, it’s the software, not the hardware. To run a VM, a virtualization software layer that provides the mapping between the VM and the host machine hardware is required. This includes network connections, USB ports, and other peripheral devices.
Virtualization and offshore central control systems
Virtualization technology is important because the operation lifecycle of an offshore platform or floating production storage and offloading vessel (FPSO) averages at least 20 years—including the control system. However, the technology of the controller and other elements of the system changes so quickly that the computer’s hardware and operating system (OS) should be updated every three to five years, if not more often. Computer workstations can be upgraded a little less often, maybe every five to seven years. Otherwise slow performance could hinder production.
This leads to a conundrum. While an offshore central control system can last two decades, the technology supporting the system is constantly evolving. Upgrading that system can be difficult, expensive, and time consuming, as migration requires constant vendor support to reinstall application software and even start new installations with an updated control system.
The central control system is a critical element of an offshore platform because it supervises, monitors, and controls all operations and safety applications (see Figure 2). This integrated automation system includes the process control system, emergency shutdown, and fire and gas. Typically, a central control system requires multiple work, engineering, and application stations, usually based on an industrial computer running on a Microsoft Windows OS.
Technical challenges on an offshore platform
The main cause for concern with an offshore central control system computer station is the mean time to repair, which can take two to four weeks at best, partly because computer workstations are not typically viewed as spare parts. When ordered, the maintenance engineer often does not have the capability to reinstall the system application software. That puts the operation at the mercy of the vendor’s on-site service schedule, which could incur unplanned cost and downtime.
Adding to the difficulty is the lack of technical resources—typically operator training—because it is expensive (requiring multiple workstations) and time consuming. It’s also difficult to get technical support on an offshore platform. Usually there’s just one instrument control engineer on a wellhead platform, and it’s hard to coordinate the service on an offshore platform with the resources onshore.
Benefits of virtualization
Taking these challenges into consideration, virtualization technology offers advantages for an offshore platform. Virtualization changes the specific platform of a host computer, and the traditional computer station with an OS and application software will become files. Those files can run on a general host computer. As new technology becomes available, the user can upgrade or change that host computer.
Figure 3 shows the typical architecture for a central control system with virtualization technology. As opposed to an entire system, a maintenance engineer will only manage the series of files. If part of the system shuts down, the host computer is independent from the application software. If a failure occurs in the host computer, the maintenance engineer can quickly get the system back up and running by copying the files to a new host computer. This transition can happen without a call to the vendor for support and without stopping production.
Virtualization also works for applications that require automatic backup and redundancy. This is a must-have for offshore platforms and especially for operators striving for the highest level of safety to protect personnel, assets, and the environment while maintaining maximum uptime and minimal operational disruption.
Virtualization offers complete fault tolerance functionality for workstation applications. Fault tolerant options make it possible for VMs to execute simultaneously on two physical servers so there’s a smooth transition in the event of a hardware failure.
Virtual deployment considerations
Considerations that affect virtualization deployment include:
- Understanding the upgrade cycle: Virtualization helps extend the life of control systems so users can create planned, predictable upgrade cycles. Servers and workstations can be upgraded/replaced without changing software or involving engineers.
- Knowing the limits: With virtualization, applications can be shared securely on a single server, allowing consolidation and increased use.
- Evaluating needs: Software updates and patches can be centrally deployed. Problem clients can be reset and new systems provisioned in the same manner. Disaster recovery is centralized, and security is further enhanced through the ability to permit or revoke user access.
- Minimizing failures: Machine failure doesn’t automatically equate to downtime as is too often the case with physical servers. Hosts monitor each other and their virtual machines for failure. If a virtual machine fails, it’s automatically restarted in a different location where available resources exist.
– He Qihong is the design engineering manager at Cnooc China Co. This article has been translated from Control Engineering China. Edited by Eric R. Eissler, editor-in-chief, Oil & Gas Engineering, firstname.lastname@example.org.
Original content can be found at Control Engineering.