Compression-set packers dominate permanent and retrievable applications. The elastomer is axially compressed, causing radial expansion. The design must account for extrusion gaps; anti-extrusion backup rings made of PEEK, PTFE, or metal mesh prevent the rubber from extruding under high pressure and destroying the seal. https://globalsealstech.com/product-category/oil-gas-seals/downhole-completion-tools-seals/