Automated Pump Control – A Case Study
The Situation
A client in South America began observing their fields using GRC’s Progressive Cavity Pump (PCP) downhole pressure and temperature sensors. Initially the client was pumping with a variable speed controller at 35 Hz the first month of installation. After one year of observation with automatic control, the unit was running at 59 Hz following the installation of GRC sensors. The client concluded that they had been losing approximately 20% of their production due to normal wear and tear of the pumps.
The Problem
As the client’s PCP pumps began to wear away, pressure would build up in the well and less fluid was being produced. Because sensors were not installed on the pumps, the client could not know to increase pump speed and was unaware of the reduced efficiency of the pump. Conversely, when pressure decreased, the client could not know to reduce pump speed to prevent premature pump failure. This critical information was unavailable using a Variable Frequency Drive (VFD) which only provides an estimation of the pump speed and controls the pump.
The Solution
The client selected Amerada pressure and temperature sensors to be installed on their PCP pumps. Combined with the surface controller tied to the VFD on the well, the client could begin adjusting their pump speed according to the pressure at the bottom of the well. This critical pressure data from the GRC Amerada sensor directed the pump to produce less when the pressure decreased and to produce more when the pressure increased, all while holding the bottom-hole pressure constant. This allowed the client to have day to day decisions on the pump speed determined automatically and on a continuous basis. The Amerada gauge provided a noticeable improvement over using traditional methods of determining the pump speed utilizing a fluid level instrument or rod torque.
The Result
With the Amerada pressure and temperature sensors installed on the client’s PCP pumps, the client has seen a remarkable 20% increase in production. The client has achieved maximum run life of their pumps due to a drop in damage resulting from loss of fluid in the well. Additionally, the client now has the capability to run a “build-up test”, anytime the pump is shut down. This is a feature not obtainable from the traditional method of determining the pump-off control of wells pumped with PCP pumps.
Without GRC’s pressure and temperature sensors installed, the client’s pumps were constantly operating at the same speed without making production adjustments due to pump wear away. The client’s investment to add the Amerada gauge was insignificant when compared to the loss of year revenues. The client now enjoys increased production and equipment that last longer.