Downhole seal stacks are vital for zonal isolation in Australian oil and gas wells, comprising multiple elastomeric elements like HNBR, FKM, and PEEK rings stacked to handle 15,000 PSI and 200°C in Cooper Basin operations. These assemblies prevent crossflow between production zones, using anti-extrusion backups and interference-fit designs per API 19TT standards. https://globalsealstech.com/product/seal-stack/