Abstract

Peregrino is a Brazilian offshore field which has been operated by Equinor since 2011. The fields crude oil viscosity ranges from 129 to 364 cp and the API gravity varies between 13° and 15° API. Electrical Submersible Pumps (ESP's) were selected as the Artificial Lift method to produce the heavy oil from Peregrino. The ESP equipment design has been modified throughout the years to address various failure modes, therefore improve system reliability by adapting customized solutions. This paper describes in detail the ESP application and solutions implemented in the field to overcome those challenges.

Every ESP string pulled from Peregrino is dismantled and inspected and this paper will discuss the routines used to conduct failure analysis and continuous improvement.

The main challenge with the ESP operations in Peregrino has been asphaltene precipitation in the seal sections and emulsion formation. Emulsion instabilities cause pressure, temperature and electrical current fluctuations, which increase stress in downhole equipment. This paper will discuss how the ESP equipment in Peregrino has been improved to meet the various challenges, an overview of the following equipment changes will be discussed:

  • Packer penetrator

  • Pump diffusers

  • ESP Motor

  • New Seal construction

An overview of the ESP equipment reliability spanning the lifetime of Peregrino's operations will also be described in this paper.

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