The ARC View “PEMEX Onshore Developments Feature End-to-End Wireless” highlights the difference between the wireless sensor network and the wireless backhaul:
http://www.arcweb.com/strategy-reports/2014-08-01/pemex-onshore-developments-feature-end-to-end-wireless.aspx
Today the focus of wireless is very much the wireless sensor network used at the sensor-actuator level, primarily WirelessHART, because it is a relatively new technology. However, only a few years ago wireless was only used as the “backhaul” network in a SCADA system; between the RTU and the HMI/SCADA software. SCADA system with RTU is very common in the oil & gas industry since many years ago and continues to be so today, particularly in the upstream oil & gas industry.
ARC explains SCADA systems in upstream oil & gas consist of RTUs and transmitters at well pads that send process measurement to control centers located many kilometers away. The SCADA system's backhaul network typically uses wireless. That is, SCADA systems today may use both a wireless sensor network and a wireless backhaul network; albeit using different wireless technologies.
ARC notes that the major wireless backhaul technology options are GSM/GPRS, WiMAX, Wi-Fi, and proprietary radios.
ARC brings up a notable example “State-owned PEMEX has an ambitious plan for developing onshore oil & gas resources in its North Region of Mexico. This calls for completing over 1,000 wells in the Veracruz area over the next few years. To support these new installations, PEMEX has standardized on equipment both at the well pads and throughout the upstream system. Instruments at most of the remote locations will use IEC 62591 (WirelessHART) communication that will be managed by a WirelessHART gateway at the well pad. That gateway provides an Ethernet network connection that needs to be backhauled to PEMEX's SCADA system.”
Where locations had GSM/GPRS coverage, GSM/GPRS modems was the backhaul choice in these locations. Other sites in this and many other SCADA systems use proprietary sub-gigahertz radios operating in unlicensed ISM bands.
ARC notes “Upstream oil & gas applications for wireless backhaul have been one of the most common wireless applications in recent years, while well pads have also become one of the most common applications for wireless process measurement.”
That is, the wireless sensor network and wireless backhaul network complement each other. WirelessHART, Wi-Fi, and WiMax etc. complement each other, they are not competing. Multiple technologies are required because one size does not fit all.
What technology do you prefer for the SCADA backhaul?