Two Decades of ESP Operations at Cerro Dragon, Argentina: A Comprehensive Case Study

Abstract

Abstract The Cerro Dragon field in southern Argentina has a large number of wells producing multilayers as the main characteristic of the Golfo San Jorge Basin. When the first ESP was installed, it was done above the perforations to guarantee the correct cooling of the system, but this resulted in not being able to produce the resource optimally. The idea of advancing in depth and between perforations opened a door for shrouds utilization. The campaign started with less than 50 wells in the first year, today more than 1000 ESPs are running. A large list of improvements has been applied for guaranteeing refrigeration, deeper the ESP to enhance recovery, solids control, pressure loses due to small spaces, etc. The ESP system has evolved to face field requirements. A hundred changes on motor technology has improved rig times and has taken overall energy efficiency to another level. Several lessons have been learned thru the time. Today, the 10% of the field are considered high run life equipments accumulating more than 2000 days of run (~5.5 years of continuous operation), exposing some assets in the fields with the eldest equipment running reaching almost 8400 days (23 years has been the biggest record). Currently, the average run life is surrounding 1000 days run. The standard equipment corresponds to 375 series with 4-1/2" shrouds, stablishing clearance as a special factor to be considered for the design and installation, nowadays 95% of the field concentrate this structure. The other 5% corresponds to the bigger equipment (450 series with no shrouds), locating this sizing upper the perforations as a lesson learned. Cerro Dragon has also been a source of field trials for different technological developments regarding improvements and evolution of the ESP system. Having carried out the first pilot tests for PMM installations, that today reached more than 140 motors installed from this technology. New challenges appear every day in the industry and Cerro Dragon is not the exception to this rule. The implementation of deep tube for gas handling, non-standard tubes for shrouds, operating temperature near the limits, development of high temperature sensors, coatings for pumps, algorithms to detect scales, 103 improvements in motors, long ESP strings with multi-tandem, are just a few to mention in the list of novel applications used.