The need for more data at higher speeds has highlighted a need for faster and more robust I/O capabilities. Automation electronics manufacturers have focused development efforts on plunger lift control applications in recent years with the objective of optimizing the time-based shut-in procedures. Additionally, technology providers offer modules with powerful data concentrators that can combine with existing I/O points to create a complete system for connectivity where large amounts of high-speed data need to be transmitted in challenging environments. Some I/O technologies also offer solar and battery power options that support faster polling times without operators having to invest in a complex power system that maintains power in remote locations. Oil and gas companies have many options for plunger lift automation, and with advanced I/O technologies it is possible to automate multiple wells on a single pad.

Data collection methods

Wired I/O is often considered the traditional method for automated data collection. For many of the first multiwell pads, producers deployed buried cable from the wellhead and pad site I/O sensors to a centrally located flow computer or remote terminal unit (RTU). This conventional method quickly became redundant and excessively expensive. For instance, the central controller is often located hundreds or even thousands of feet away from the wellhead, requiring extensive amounts of cable. Additionally, crews must dig separate trenches for each wellhead on the pad. Many multiwell pads also have several tanks gathering liquids for 12 to 16 wells. While larger horizontal wells can improve surface land use and help cover a larger area with a single facility, the number of critical I/O points to monitor can be quite large. When using a wired solution, the wiring from the wellheads to the tank batteries often needs to be placed under access roads for trucks that transport liquids from the tanks to other facilities. The continued heavy weight of the trucks and high volume of traffic often contributes to the destruction of the buried cables. Depending on the locations and soils, some operators will replace their buried cable in less than a year, which is an expensive proposition. Additionally, lightning also can pose a threat. Upon striking a piece of equipment, say a pressure transducer, the lightning could potentially travel through the cable and destroy a much more expensive piece such as a flow computer, RTU or power level controller (PLC).

Wireless I/O automation technology can enable transmission of hundreds of data points in real time. When the right wireless I/O technology is selected, it has the potential to address all of the automation demands resulting from advanced drilling and artificial lift techniques while offering a lower total cost of ownership and a dependable solution. Some of the key traits of wireless I/O when properly selected and installed include:

  • Cost effectiveness. Wireless machine-to-machine (M2M) communication technologies are easily deployed at the wellhead and eliminate the need for trenching and the expenses associated with running wire over long distances;
  • Quick installation. With adequate network engineering support, wireless I/O radios can be easily installed in a fraction of the time of a wired solution. Additionally, a full pad site could be easily configured and installed in a single day;
  • Maintenance. There are providers that offer up to three-year warranties, excellent power utilization allowing lower cost power systems and firmware that is upgradable, all of which are factors that dramatically reduce the need for frequent maintenance;
  • Flexibility. In the event that the wireless radios need to be relocated, they can easily be moved. Additionally, some wireless I/O technology can be configured to communicate with previously deployed RTUs and PLCs, allowing a producer to expand its I/O count while using existing equipment, saving significant upgrade costs;
  • Ease of use. Some wireless I/O solutions have configuration templates and can be configured right from the operator’s desktop; and
  • “Fail-safe” option. Some wireless I/O technology can initiate valve closure or preprogrammed “safe” I/O states if communication is lost.

Maximizing production

In production, wells tend to lose natural pressure over time, and their ability to bring NGLs, oil and gases to the surface significantly decreases. In the past a trained operator might manually shut in the well to increase pressure downhole and stimulate production in a well that suffered from fluid loading. This method was designed to build enough downhole pressure to lift and produce the liquids from the well. To maximize production, producers began using artificial lift as a more efficient process for lifting liquids, then adding automation to redirect man hours and manage the large liquid loads. With any automation process, monitoring and control technologies are used to ensure that pressures and temperatures are regulated and valve control is automated. With some artificial lift techniques, trying to produce the well too quickly can potentially damage equipment while also reducing total production. The result is reduced daily revenues. By using wireless I/O technology, pressures can be closely monitored to ensure optimal function.

Rod pumps are one example of an artificial lift process that can use wireless I/O. Pressures and loading are critical to ensuring the pumpjack, rodstring and downhole equipment are optimized to lift the liquids to the surface.

Gas lift is another process for extracting fluids from the well that requires tight control of the overall process for optimum production. With any type of liquid-rich artificial lift, not only will there be the obvious pressures that require monitoring, but tanks need to be monitored as well.

Plunger lift often is used to deliquify a natural gas well. To improve this process, producers use a plunger to assist with lifting the fluid. With the right well conditions, plunger lift is quite effective, but it must be used correctly. Incorrect use or excessive plunger travel speed can damage the plunger equipment, having a direct negative impact on maintenance cost. On a plunger lift well, the data most often transmitted include level, flow, pressure, temperature, plunger arrival, alarms and signals generated to manage the valve and overall system.

Electric submersible pumps are submerged into the liquid they will be pumping. Monitoring the well and pump conditions is critical to prevent damage. By remotely monitoring critical data points such as pressure, production volume and line pressure, an operator can achieve maximum production results at minimal cost and minimum risk for damage.

As advances in drilling and artificial lift are used to create significant increases in oil and gas production, there is an increasing number of data points that producers will want to bring into their RTUs and SCADA systems. As liquid production increases through the drilling of tight oil and liquids-rich shale plays, monitoring becomes more critical to help ensure a seamless production process. Multiwell pads have revolutionized the way oil and gas is produced, but producers may be challenged to find the most effective data collection system. By using wireless I/O for monitoring and control, there are numerous benefits such as flexibility, ease of use and major cost-saving opportunities.

Industrial-grade M2M wireless communication technology is proven to be a reliable and secure method for data collection. As multiwell pads continue to require more data, expandable I/O is a viable option that maximizes monitoring points without requiring a major equipment overhaul. At some point almost every producer will need to evaluate its existing communications networks and determine whether it is using a technology that optimizes production. It is critical to stay ahead of the curve when it comes to technology options and select a solution that will flourish in an individual production scenario.

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