Challenges in ESP Operation in Ultra-Deepwater Heavy Oil Atlanta Field

摘要

Atlanta is a post-salt oil field located offshore Brazil in the Santos Basin,185 km southeast of Rio de Janeiro.The combination of ultra-deepwater(1,550 m)and heavy and viscous oil(14 °API and 228 cP at reservoirconditions)composes a unique challenging scenario for Electrical Submersible Pump(ESP)application.The paper discusses the performance of the ESP system utilizing field data and software simulations.The in-well ESP is the main production method and mudline ESP boosting is the backup one.Bothconcepts proved to be effective artificial lift solutions for the harsh flowing conditions.The in-well ESP isinstalled inside a capsule in a close to horizontal slant section of around 70 m.The mudline ESP boostingis readily available to become the main production method in case the in-well ESP fails.This paper discusses the challenges and solutions that proved to be successful after more than 18 monthsof continuous production.Software simulations and continuous production monitoring were key factors forsystem modeling and optimization.One of the most powerful ESPs installed inside a well worldwide to produce heavy and viscous oil froman unconsolidated reservoir represents a step forward in ultra-deepwater production system boundaries.The concept of having the mudline system as backup is also an innovative step for the offshore oil andgas industry.Two production periods are presented with very distinct and unusual characteristics:(i)one producing12,500 bpd of a high viscous,high Gas Void Fraction(GVF),low inlet pressure and temperature crudethrough two mudline ESP boosting systems and(ii)another one producing 30,000 bpd through three in-well ESPs.