Evolution of Open-Hole Gravel Pack Methodology in a Low Frac-Window Environment: Case Histories and Lessons Learned From the Kraken Field Development

Abstract

The Kraken field development was planned and executed through several batch drilling and completion phases to allow a review of each phase and incorporate the lessons learned in the next phase. All producers were drilled with an oil-based reservoir drilling fluid (OB-RDF). The lower completion with shunted sand control screens was installed in conditioned OB-RDF, followed by displacements to water-based fluids after the packer was set. Gravel packing was performed with a visco-elastic surfactant fluid, and a breaker treatment was spotted across the open hole prior to isolating the open hole with a fluid loss control valve. This paper discusses the design, execution and evaluation of the lower completion phase for the development of the Kraken field in the North Sea. This includes detailed reservoir evaluation, methodology followed for sandface completion selection, steps taken to improve efficiency through lessons learned and continuously extend well lengths to be gravel packed in a low frac-window environment, and well performance results in this 24-well field development, with focus on the 7 out of 13 oil producers, detailing 3 of them.