Abstract
"What gets measured gets improved."
There are many different methods in the industry in measuring the ESP performance. Average run life for active ESPs and/or for inactive ESPs and/or for all ESPs is a simple method to calculate average run life for a certain population but the result maybe misleading especially it maybe change up and down greatly due to high or low frequency of new installations. MTBF or MTTF method is preferred by some companies but the result maybe misleading too. MTBF or MTTF is not service life and the calculation assumed constant ESP failure rate which is not a reality. It is therefore difficult to understand real ESP performance subsequently hard to identify areas of improvement.
The Kaplan Meier method is another widely used one in reliability analysis. The MTTF is calculated as the total area under the Kaplan Meier curve. This paper uses the same method but for a basis of rolling datapoint, plotting R(90), R(180), R(270) and R(365) monthly progression. The trend could indicate the reliability improvement over time or at specific period due to specific in ESP applications. It could also visualize the deterioration of the reliability due to improper way of operating the ESP. 1 year data rolling is used for reflecting better the changes of R(90) and R(180). 2 years rolling data is recommended for R(270) and R(365). This new reliability metrics for ESP performance analysis has been successfully used in US Land.
Raw data would need to be extracted from business system or local tracking database. This should include as many details as possible, such activity date, pull date, customer, county, depth, casing information, Pump/Motor/completion types, BHT, well conditions etc. Upon calculation after process the raw activity data, the monthly evolution of the R(t) over time since January 2020 are plotted out. Such graph visualizes the changes of reliability until May 2024, at the time of the paper is being drafted.
By analyzing the rolling R(t), directions of improvements are clear, and area of improvements then can be promptly identified with the common tools and methodologies such high tier DIFA.
Some operators changed the fracking process after they acquired the asset from previous operator. The reliability dropped and stayed at much lower level for all R(180), R(270) and R(365), due to the heavy wear from much more sand production. The comparison of reliability before and after the acquisition, and among peers in the same region are presented clearly that the need of review the fracking service and technology of sand avoidance, and upgrade the ESP metallurgy so as to improve the longevity of the ESP.
Some operators where there is large volume of installations monthly improved the ESP reliability over the time continuously, through successfully implementation of new technologies, DIFA and engineering upgrades/improvements.
