Operating an ESP During a Frac Hit

Most frac hits are significant events with large pressure change, followed by enhanced flow of almost all water then declining with increasing oil at a level higher than before the event.  This study examines how best to “ride thru” the frac hit, but also how to manage ESP settings for the rapid fluid rate changes during and after the event.  The frac hits occurred at different points in the wells drawdown so The ESP operation was monitored and setpoints adjusted as needed with the changes in load.  The increase in rates were much less than initial production and peaked after initial pressure change.  The delay from pressure peak to flow peak, was about 6 days on average.  So, what was seen at first was pressure spike above the previous operating point after about 14 days.  Then the flow increased to its peak.  In the interim where the well experiences pressure support and then fluids hit, some ESP’s experienced lighter loading so tripped on previous underload settings.  There appears to be slightly longer runtimes on wells that have seen frac hits most likely due to the ESPs running closer to the original sizing and with lower gas.  From evaluation of times to fail after frac hit and DIFA’s of those failures, it is probably best to keep the ESP running during these events.  After the wells’ normal decline returns, it is recommended that we reset the drive parameters to the new conditions.  We note that some of these wells had multiple events so remaining run life was calculated after the first frac hit.  From a production standpoint, there does not appear to be an advantage or disadvantage to shutting off the ESP during a frac hit, however, ESP’s generally run longer with fewer shutdowns.