Texas Tech U. Test Bed for Rod Lift Innovation and Research

Horizontal (HZ) wells pose new challenges for Artificial Lift( AL), which is compounded by the recent increase in lateral lengths from 1-2 to 3-4 miles.  However, improved recovery and efficiency are possible when AL methods are optimized for HZ well production using improved methods, automation and machine learning.  Gas handling from horizontal wells was identified as a top remaining challenge for Rod Lift.  To address these challenges Texas Tech U (TTU) is developing new test benches to qualify new tools/methods in support of innovation. We are developing on-campus test benches to visualize and test sand fallback prevention tools while also improving the large-scale test facilities at the TTU Oilfield Technology Center (OTC) which is already equipped with a 4,000 ft well and Lufkin pumping unit and 2.0 controller.   This presentation will present preliminary results using speed control to rapidly respond to gas slugging in Rod Lift wells.  

The TTU Rod Lift “Test Bed” can create specific pump fillage conditions “at will” to test new methods for handling the gas slugging commonly seen in horizontal wells.  This new project has utilized the pump controller and an “edge device” to dynamically change the speed of the pump during the stroke or on the next stroke.  Being able to control this speed autonomously on a stroke-to-stroke basis when downhole conditions change can offer benefits such as an increase in pump fillage and a decrease in rod stress while requiring minimal input from an operator. Currently, speed is being controlled using a Variable Frequency Drive (VFD) and results will be shown for pre-determined setpoints that have been used to optimize speed from stroke to stroke, demonstrating the ability to maintain a fuller pump during periods where reservoir inflow may not be able to match the capacity of the downhole pump. Another benefit observed was the ability to maintain a higher ratio of minimum to maximum load on the rod string which can lead to a longer operating life.

Next steps in this project will control speed using a Permanent Magnet Motor (PMM) installed directly to the gear box. This will provide improved synchronous speed control. Also, a workover is being planned to install 5 ½-inch casing, a downhole pressure sensor, a capillary string and a new wellhead.  This new configuration will allow controlled gas injection from the surface via the cap string with gas entering just below the downhole pump.  We can then create a wide range of gas slugging conditions and test various machine learning algorithms and vendor products to maximize production and reduce pump shutdowns.