You don’t have to be an oil-industry insider to be familiar with wells that use sucker rod pump controls. These pumping mechanisms are installed by the hundreds of thousands in the United States and are common sights along rural roads and highways. They even have popular nicknames, such as “nodding donkey,” “thirsty bird” and “horse head,” which refer to their characteristic shape and nodding motion.
A large percentage of these classic oilfield icons are being upgraded so they can not only remain serviceable but generate enhanced well production performance. In addition to the improved production performance, modern control systems, when installed on the pump systems, also minimize operational power consumption and prolong the life of the well and the pumping equipment. One of their fundamental values is providing real-time data to operators—anywhere in the world—even when the system is remote or broadly dispersed.
When operators have real-time data, they can evaluate and predict both well performance and the pumping system condition. Now, with additional well pumping system data available, this kind of well operation can be fully automated using sophisticated control algorithms with minimal operator supervision. Because well conditions change without notice, continuous production optimization, prognostic health monitoring and predicative maintenance are all critical to ensure the wells are maximizing their production with a minimal amount of downtime. And in such a complex industry, it’s important that companies avoid leaving money on the table in the form of oil that can’t be pumped due to breaks in operation or unexpected conditions.
But as the saying goes, a chain is only as strong as its weakest link, so individual components (such as load cells) must be designed to ensure the efficiency and effectiveness of the overall control system is maximized. By upgrading control systems, companies could see an increase in profits by using a reliable pump-off control (POC) load cell that runs continuously over longer periods of time.
POC load cells are not a new technology, but early products not only experienced limited operating life when installed on the polished rods of oilfield pump off control systems; they often produced unreliable results. LORD Series CTH932 POC Load Cells were designed to be less influenced by external loading from mounting and installation, and from environmental conditions. They meet the industry’s need for a more durable cell that provides a more accurate and reliable continuous measurement of rod loading.
New Control Systems: What do they require of a Load Cell?
One key measurement for a sucker rod pumping system is the load on the pump polished rod. Using this continuous measurement, along with the rod’s position, the control system can effectively determine if the pump needs to speed up or slow down to accommodate more or less oil in the well. The dynamic characteristic of the load measurement also enables an operator (and increasingly, more advanced computational platforms, analytics and control algorithms) to determine if the pump is damaged or starting to wear. If a load cell measurement is highly accurate, prognostic health monitoring and predictive maintenance become much more feasible, leading to improved rates of production.
CTH932 POC Load Cells
Are designed for pumping extremes - Standard full-scale capacities range from 30,000 to 50,000 lbf, with a maximum load capability of 80,000 lbf. The design also includes the built-in capacity to withstand 200% of the static load range without damage due to overloading during uncontrolled operation, installation or system shutdown.
Have durable components for long life in tough operating conditions – The welded stainless steel housing with hermetically sealed internal connector and cable exit design reduce cable fatigue with cyclic motion of the sucker-rod, achieving an extended cycle life (50,000,000 cycles).
Are resistant to environmental extremes - The design is resistant to electromagnetic interface and power disturbances as well as shock and vibration that are often experienced in remote field operations. The operating temperature range is rated from -40°F to 176°F.
Have performance to enable peak control system operation - With the load cell's improved static accuracy of 0.50 percent full scale output, including reduced sensititiy to off-axis loading, the state-of-the-art sucker rod control systems can optimize pump production performance as well as ensure continuous operation through the use of prognostic health monitoring and predictive maintenance algorithms.