Open Hole Packer Movement – The Last Piece of the Puzzle, Tubular Design

Abstract

Open hole packers for multi-stage fracturing completions have long been deployed with open hole anchors with a philosophy that these anchors will enable achievement for a successful well stimulation. The general perception in the industry is that the open hole completion in the well should be anchored to avoid open hole packer movement during a fracturing job. However, some questions are still unanswered such as: Are the open hole packers moving during the fracturing job? When are the open hole packers likely to move? This paper takes looks at several open hole packer movement analyses during stimulation. To analyze the objective of this study, the focus was kept on the analytical open hole packer force and the movement tendency during a stimulation job. To answer the questions above, it is essential to evaluate analytically the effect of these induced axial loads during fracturing with open hole packers, which have been set with and without use of open hole anchors, in the completion string. Hence, this paper discusses the study and influence of; 1) high pressure and cooling effect during stimulation, 2) friction force associated with open hole packers, and 3) maximum force required for open hole packer movement, and 4) packer movement lab test data. The results from open hole packer movement analysis performed for several cases has successfully estimated the maximum force needed for packer movement. The study addressed the un-answered questions and showed the requirement for either complete anchoring of all open hole packers or total elimination of open hole packer anchors during hydraulic fracturing. Uncertainty of potential tubular failure, due to misinterpretation of open hole packer movement, can be determined earlier during the concept design stage, to avoid well integrity issues during the stimulation operation.