Universal Master Control Station
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On the top-side facilities of offshore oil and gas platforms, the Master Control Station (MCS) is a dedicated system that controls and retrieves data from subsea equipment on the ocean floor. The MCS was supplied by the manufacturers of the subsea control modules (SCM), and included companies such as Aker, GE (VetcoGray), Cameron and FMC. These "proprietary" solutions limited the operators ability to expand their existing fields with different vendors, because each MCS could only communicate with a single vendor's SCMs.
Positioned between the distributed control system (DCS) on the platform and the subsea equipment, the MCS is critical to maintaining safe operating conditions, optimizing production across a field and effectively managing reserves[1][2]. The complex automation systems enabling offshore production of oil & gas, particularly in deep water, have strong parallels to their on-shore, process plant applications. However, only recently have conventional automation practices for on-shore process plants been applied to subsea production control systems[3]. These practices include the necessity for systems, subsystems and instruments to interoperate in a seamless manner[4].
Realizing the opportunity for greater standardization in the offshore process control environment, some of the largest oil and gas producers began planning a Universal Master Control Station (UMCS). In 2008, Control Dynamics International of Houston, now a subsidiary of ENGlobal, was commissioned to further develop the concept of developing an MCS that could communicate with and control subsea equipment from multiple vendors.
Contents
Design Considerations & Objectives
The primary focus of the UMCS development program was to create a new global standard that used commercially available, off-the-shelf components. The graphics, control routines, and logic/communication functionality would be designed and implemented to provide operations a recognizable control system. A standard interface (communication protocol) would establish a common communication link for the UMCS enabling concurrent data exchange to multiple subsea vendors.
Oil and gas producers needed a universal product that could:
- Communication and control up to 100 Subsea Control Modules (SCM)
- Expandable in the field
- Based on commercially available, off-the-shelf hardware lowering the OPEX of the implementation
- Components replaceable without well shut-in
- Dual redundancy to alleviate a shut-in due to multiple points of failure
- Communications with subsea equipment based on a widely accepted standards
- Open architecture for integration with third-party subsystems
Standard OPC databases serve as the communication link to the Distributed Control System (DCS), Hydraulic Power Unit (HPU), and Electrical Power Unit (EPU). The UMCS will communicate with subsea control pods at the wellhead from multiple subsea equipment providers, without disrupting the subsea vendor’s native communication protocol.
Physical Architecture & Connectivity
The UMCS has three main layers: HMI, logic/control and subsea communications to control pods on the ocean floor. Two complete and segregated channel networks simultaneously monitor data functions to and from each other, as well as between surface and subsea equipment. The UMCS uses OPC for communications with each subsea gateway. The subsea gateway consists of the SCM communication application and OPC Client. Each subsea vendor provides their own gateway, thereby preserving their traditional proprietary design and safeguards inherent in each system. This scheme alleviates the need for modifying any subsea vendor’s communication link or SCM, but allows the design of the SCM to be evolved without affecting the UMCS. The UMCS enables multiple subsea vendors to connect to the same MCS via Ethernet.
Software Applications—the Core of the UMCS
The UMCS utilizes a set of core graphic screens with a variety of control pop-ups, trending screens, diagnostics, and alarm handling. Screens can be quickly configured to project-specific requirements using any off-the-shelf human-machine interface (HMI) software. Custom programming is minimized or eliminated altogether and is replaced by HMI screen configuration, making the UMCS extensible and easier to maintain.
Tangible Value of the Universal Master Control Station
The system is also designed to accommodate multiple wells, and integrate with the major distributed control systems (DCS) and subsea equipment types. The UMCS also offers a pre-engineered solution based on a standardized program block architecture and a common communication database via the Standard Interface, based on OPC.
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