Page 97 - Intelligent Digital Oil And Gas Fields

66 Intelligent Digital Oil and Gas Fields

Signal speed

Wellhead monitoring
Ethernet switch
board
Wireless AP/bridge

Smart Sensor
meter RTU
Controller
Cable

Fig. 2.12 Well-location equipment for data receiver and transmission. (Image courtesy
of Moxa.)

commonly mean the use of fiber-optic cable to the optimization and col-
laboration centers. Most of the other means have too much latency or
subsampling to enable DOF workflows. Widely scattered assets, like the
shale plays, require some wireless technology. Although commercial
cell-modem communication is getting more affordable, the variability of
plans makes it difficult to fit into a DOF strategy. Therefore, it is most
common to see radio-frequency towers used for DOF assets. This area
of technology is rapidly evolving so the DOF best practices will be chang-
ing very soon.
The IT infrastructure for data gathering is commonly a data historian.
This software provides both a data and hardware gateway between the
more-secure local control site and the enterprise IT-based DOF systems.

2.3.2 Field Control Devices

While DOF workflows require more data to be communicated up to the
enterprise servers and systems, more control and processing power is being
pushed to the well pad. It is now very rare to find simple RTU-type units on
the well site (as shown in Fig. 2.12). Almost all DOF assets use remote oper-
ation centers (ROC) at least. A new version of old technology is the
reemergence of PLCs. PLCs have tremendous programming capability
and are commonly used in high-frequency manufacturing. These are very