Design of Self Swellable Casing Centralizer for Zonal Isolation in Petroleum Wells - A Utility Model of Well Completion Tool

Abstract

In view of the problem that fluid channeling between zones resulting from poor quality of cement sheath, a new casing centralizer is designed. The centralizer can make casing string in position as usual and seals micro-channels by the oil/water swellable rubber. Swellable rubber slices are inlaid in centralizer edges to add sealing efficiency. In order to seal diversion trenches effectively, axial moveable rubber bars are designed. During slurry injection, rubber bars are pushed upwards by differential pressure to open the flowpathes; after displacement, rubber bars reset under spring force. So, a circular sealing strip is formed by rubber slices and rubber bars for zonal isolation. In the paper, structure and working principle of this tool are described, materials and components are matched, structure strength is calculated, and the feasibility of the new tool is discussed.