Wireless Telemetry for Oil Field Pumps, Tank Batteries and Pipelines
Summary:
- Old system required drive by monitoring
- New system: DAQFactory remote monitoring
- UHF radios and autodialers
- Complete monitoring, control, and alarming system with autodialing
- Remote access to DAQFactory server connecting to remote systems
CNW is a company owning oil pipelines, transfer pumps, oil wells and tank batteries in the Oklahoma City area. For several years they have used RFScada equipment at several 'stand alone' locations which typically have a tank battery being supplied from remote pumps; the original RFScada equipment was primarily used to prevent tanks from overflowing. Some of the sites had alarm dialers for basic alarm notification, others had lights that could be seen from the freeway, and others had nothing but frequent pampering by 'pumpers', the oilfield operators. One or more pumpers would drive from site to site all day and monitor activity, stopping and starting various pumps, adjusting flow settings, tank level trip points etc. Even a short power interruption that took down part of a field would require hours of coordinated effort with several people to bring the field back up, as pumps had to be enabled in certain sequences when conditions were suitable. The sites are spread out over a distance of about 8 miles in heavily populated residential and commercial areas, with freeways, shopping malls, railways and rivers separating sites. There were other challenges: spills from tanks or pipelines (several very old and crossing rivers) could be catastrophic plus many sites are in areas subject to theft and vandalism; equipment costing thousands of dollars had been ruined as thieves cut live high voltage copper cables on running equipment.
In 2006 Mark at CNW asked Data Delivery Devices (DDD) to implement a SCADA system to improve the situation. DDD RFScada telemetry products have been used on many similar oil field systems before, and all of them use DAQFactory as the PC SCADA interface. Some of the larger ones have hundreds of I/O points and alarms, spread over 30 miles between sites; some are simple with just a few I/O points such as a rural water tank and pump. Although each system is different most have similar common components such as alarms, logging and graphs. Over several years DDD has built a DAQFactory application which has become the core of its telemetry and SCADA systems; it encompasses all functions that are common for this type of application. Building a new application for customers such as CNW can now be done very quickly, since all that is needed is to design the application specific screens, define I/O that will be needed and enter site specific data such as alarm and statistical conditions. Many of these tasks, such as creating a new alarm or calibrating a new flow transducer may be performed by the operator as the application runs -without requiring a 'guru' programmer or even stopping the program. There are many benefits to this especially at very remote sites without internet, phones and service personnel nearby.
Mark's system required installing an RFScada unit with a 5 Watt UHF radio at each site, with these radios small whip antennas provide communications back to the office several miles away; the antennas are not obvious and are located out of vandals reach. All existing auto-dialers were thrown away and phone lines disconnected - an immediate saving from several phone lines. A PC running DAQFactory was installed at the main office with a 5 Watt UHF radio connected to the serial port. DAQFactory directly generates and decodes the RFScada 'over the air' protocol which compresses much more data into a packet than Modbus; an important consideration with wireless data that is much more likely to be corrupted with larger packets. Another benefit is a very fast scan time, in this application every unit and every I/O point in the whole system is accessed by DAQFactory at least every 10 seconds, so alarms may be set with very short trip times. The PC also has a voice modem for alarm callouts and is connected to the internet so it may send emails, plus be accessed remotely.
Operating the lease has been completely different since the system has been implemented. All activity may be monitored and controlled from the main office plus graphs going back months display pump activity and flow rates through various pipelines; changes in flows are monitored to help identify leaks. Pumps may be directly controlled and set-points adjusted from the DAQFactory application, without requiring a site visit. With the applications standard capability to handle alarm groups, 'on duty' time & day shift rosters for phone dialing and text messages alarm callouts are now much more flexible plus easier to configure. Alarm text messages may be sent simultaneously to all pumpers cell phones, at the same time the dialer calls out to the first 'on duty' pumper and speaks the alarm. If the callout is not acknowledged or answered then the application calls the next on duty employee, cycling through them all until it is acknowledged. Using alarm groups allows certain alarms to be routed to different groups of pumpers that may be responsible for different lease sections. All activity is logged to daily history files along with accumulated statistics, such as pump stop / start cycles.
As an additional benefit the office PC running DAQFactory may be remotely accessed using another PC, PDA or cellphone with internet access. Now an operator standing in the field next to a well is able to make changes in seconds and observe activity, even to equipment miles away. The complete system may be observed and controlled without even returning to the office. Running the RFScada / DAQFactory application has drastically improved the lease operations, and CNW will be adding another 10 sites in the next few months. The upgrade probably will not even need a site visit, since RFScada units will be installed by Mark's employees and the DAQFactory application can be modified remotely. Mark says the system has already paid for itself many times over, and its 'saved our rear' many times.
-Alistair Smith, Data Delivery Devices LLC