One of the major impacts on progressing cavity (PC) pumps is the amount of free gas that enters the pump intake. PC pumps can handle increased amounts of free gas but under certain conditions this can have detrimental consequences on pump life, decreasing pump performance and pump production capacity. The higher the gas rates through the pump the higher the internal temperature. This temperature increase accelerates elastomer degeneration and fluid penetration into the elastomer to the bonding agent. Having a high volume of gas entering the pump decreases the amount of fluid slippage which does not allow for an even pressure distribution throughout the entire length of the pump. This uneven pressure distribution increases the workload to the discharge of the pump causes a premature failure. In order to overcome these issues charge pumps technology was tested.
The study was completed in the Orinoco Belt, Petropiar field. This is an unconsolidated sandstone formation with high fluid flow rate wells, 430 bbls/d at an average of 11° API. Reservoirs change through their productive life varied the operational conditions in the Orinoco Faja wells. Historically intake pressures were higher than 500 psi, GORs average 25 scf/stb resulting in free gas levels lower than 50%. Recently, data shows intake pressure lower than 250 psi, GORS higher than 1000 scf/stb resulting on free gas levels over 90%.
This is the first charge pump installed in Petropiar field. The strategy for this project was to start identifying well candidates where charge pumps can improve the PC pumps performance through gas separation and reduction of gas volume fraction (GVF) at pump intake. It also considered a well facility's conditions in order to get more variables and the most accurate information for this trial evaluation. The overwhelming results after installing the charge pump allowed the expansion of this technology to different wells with similar conditions regardless of well fluid production rate, sand, or water cuts. This is all part of a combined effort for finding reliable and cost effective solutions for challenging applications.