What wireless network?

The Cockrell Ranch Waterflood project is a challenging enhanced oil recovery project located in the Texas Panhandle. Cano Petroleum uses state-of-the-art technology and methods to recover oil from wells that once would have been considered tapped. The waterflooding process uses pressurized water to move through the formation, driving raw crude oil out of the ground from wells.

Boss Automation of Spearman, Texas, was brought in to design and install a discrete automation platform and control network to monitor pressure and flow of water into wells. The project evolved into the design and implementation of a new, fully automated, self-monitored SCADA system. The system was designed to gather, assemble, and transmit data from wells and injectors and ultimately bring it to a master station. This allowed the daily field operation to be monitored and controlled from the sites and allowed collected data to be used to produce detailed production models.

Considerations for the system included reliability, maintainability, ease of use, and ability to obtain local support. With the aid of Rexel, the local Allen-Bradley distributor, Boss Automation decided on a combination of Allen-Bradley hardware, Rockwell Automation software, and ProSoft Technology wireless communication solutions.

The map illustrates the master station, backbone network, and subnetworks for the project. (Images courtesy of ProSoft Technology)

The system
The SCADA system consists of one ControlLogix at a main master station tied to four ControlLogix slave substations and more than 100 custom-built remote terminal units (RTUs), each comprised of an Allen-Bradley MicroLogix 1100 programmable logic controller (PLC) and a ProSoft Industrial Hotspot radio. The main master station and four substations represent the project’s backbone network. Each of the four substations acts as a master for its respective sub-network. Communication from wells and injectors to substations, and from substations to the main master station, is handled wirelessly using ProSoft’s Industrial Hotspot solution.

Paul Brooks, business development manager, Networks Portfolio for Rockwell Automation, said, “For this application, ProSoft’s wireless technology provides the backbone communication for the integration of the system, creating a reliable, industrial, and transparent network that allows Cano Petroleum to successfully monitor its process data remotely."

At the main master station, a human-machine interface application for the system was developed using Rockwell’s RSView 32 software. Graphical interface screens have proven user-friendly, and the Messenger Pro feature provides operators with detailed information about alarm conditions in human voice by automatically calling the cell phone of the person on call. ProSoft’s RadioLinx OPC server is used on the remote-access computer to monitor radio network status.

More than 3,500 discrete input/output as well as 1,000 analog points are gathered and moved across the wireless network at about 11 Mbps to the main master station, where they are assembled into datalog models and then interfaced by Cano’s own proprietary modeling software.

Planning makes perfect
Rexel was instrumental in providing logistical and technical support for the project. With respect to the large-scale wireless network, ProSoft provided engineering support throughout the duration of the project.

Patrick Haga, ProSoft wireless engineer, said, “From the technical side of the project, the main reason this is a success story is because of the planning and care taken before starting the project. I probably spent close to 80 hours working with Boss Automation control engineers on a path study using ProSoft’s Pathloss software. We worked very closely together before and throughout the installation of the project, not only on the layout of the network, but on the strategy for PLC messaging.”

The overall network covered approximately 12 sq miles (31 sq km) with the longest link being approximately 2 miles (1.2 km). Radios were positioned in a 3-sq-mile (7.8-sq-km) area, which presented concern. “In a radio network of this size, it is imperative that care be taken in setting up the PLC messaging,” Haga said. “If all radios are trying to communicate at the same time, you can quickly swamp your bandwidth with RF (radio frequency) collisions and retries. With this in mind, we discussed the need to create a polling-style network rather than having all the radios trying to communicate at the same time. It takes a lot of planning up front to successfully install a radio installation of this size.”

Chris Deakin of Boss Automation added, “The process is incredibly reliable and consistent and makes for an essentially self-managed site. From the main SCADA monitoring station, the operators are able to see virtual diagrams of the wells and what is going on within them as well as all the data collected by the RTUs and control units.”

The SCADA system consists of one ControlLogix at a main master station tied to four ControlLogix slave substations and more than 100 custom-built remote terminal units (RTUs).

Project results
In spring 2008, the project went live and has since had near zero downtime. “The wireless network works so seamlessly and reliably that it is virtually transparent to the user,” Deakin said. “When all was said and done, I asked how they liked the wireless network. Their response: what wireless network?”

Harry Forbes of ARC Advisory Group said, “The Cockrell Ranch Waterflood project illustrates three important points about industrial wireless. First, wireless is indispensible for this kind of SCADA project to be cost-effective. Second, end-users need to select hardened, industrial, field-proven products to provide a lifelong, reliable wireless solution. Thirdly, a well-designed wireless network can deliver data in a SCADA system with very high reliability – in fact, so high that end-users forget about it.”