Effectively operating artificial lift systems can be a very challenging endeavor when implementing tertiary recovery on a mature oil field. The desire to produce a maximum amount of oil must be balanced with the physical limitations of the artificial lift equipment. The traditional operating limitations of artificial lift equipment may be too liberal in a CO2 flood. Being too aggressive when attempting to reduce fluid levels can lead to excess failures and thus, reduced overall production and excessive costs.
Attempting to determine the optimal artificial lift strategy in this environment can be a daunting task. Traditional models for determining operational policy may not capture all of the dynamics that affect the performance of the system. An empirical approach can be helpful in setting artificial lift guidelines.
This paper discusses the results of an empirical analysis of an artificial lift system's performance in a mature CO2 flood vs. the performance in a mature water flood. For the analysis, data from two oil fields in southeastern Utah, the McElmo Creek Unit (mature CO2 flood) and the Ratherford Unit (mature water flood) was compared and contrasted. The data was analyzed using statistical modeling tools to determine the appropriate strategy for the system. The results from the review gave significant insights to the optimal strategy for operating the system and will be discussed.