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

Abstract

Abstract 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 reservoir conditions) 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. Both concepts proved to be effective artificial lift solutions for the harsh flowing conditions. The in-well ESP is installed inside a capsule in a close to horizontal slant section of around 70 m. The mudline ESP boosting is 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 months of continuous production. Software simulations and continuous production monitoring were key factors for system modeling and optimization. One of the most powerful ESPs installed inside a well worldwide to produce heavy and viscous oil from an 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 and gas industry. Two production periods are presented with very distinct and unusual characteristics: (i) one producing 12,500 bpd of a high viscous, high Gas Void Fraction (GVF), low inlet pressure and temperature crude through two mudline ESP boosting systems and (ii) another one producing 30,000 bpd through three in-well ESPs.