Handling ESP Problem Using Automatic Frequency Rocking (AFR)

Abstrak

The most typical issue with ESP is a gas lock, which causes the system to stop down and need a restart. Due to motor fires, downthrusts, a damaged shaft, and other issues, the gas lock prevents production. Gas-lock is managed by avoiding, decreasing the effect of, and removing it. By employing a gas handler, choking, and venting, gas-lock may be prevented. However, these measures have not entirely prevented the gas-lock. Utilizing Inconel shafts, Hi-Temp motors, and high-quality materials have been attempted to make gas-lock less of a problem, but the issue has yet to be resolved.

The conventional way for removing the gas lock is to switch off the ESP and restart it, however this generates further issues, such as the pump being stuck. In addition, for offshore activities, weather, boat availability, and distance must be considered in order to resume an ESP. Therefore, another way is required to remove the gas-lock without disabling the ESP.

Changing the ESP frequency manually using variable speed drive (VSD) is a typical method for removing the gas-lock without turning off the ESP. By altering the frequency, it is anticipated that the trapped gas will be forced out of the pump by the fluid. However, changing the frequency manually is ineffective for offshore activities. Instead, an automated procedure is required for greater efficiency and quickness. A controller module rather than VSD operator personnel is needed. The controller comprises a PLC, an HMI display, and setup software. The frequency changer is activated by low-ampere, low-Pi, and high-TM plus delay time trigger factors. The frequency-changing process is halted depending on time or other criteria, indicating the elimination of the gas lock. If the sign of gas-lock is recognized, the procedure will resume. This method may be performed several times throughout the day and night. This technique is referred to as Automatic Frequency Rocking (AFR).
The ESP installations at well CINE-09 were observed. The run life of the last four ESP placed in the CINE09 well is 71 days, 29 days, 39 days, and 335 days following the use of automated frequency changer AFR. The issue with ESP here is again gas lock. The graphical representation of the Ampere, TM, and Pi data depicts a periodic and continuous gas-lock removal process. When the AFR is disabled, a gas-lock develops, causing the TM to increase and therefore shutting the ESP. The AFR application successfully eliminates gas lock on the ESP pump without shutting the ESP. Using the AFR, a basic ESP systems constructed from common  materials will be able to tackle challenges in problematic wells.