Two slip retrievable packer for extreme duty

A packer includes one dual, or double acting, slip and a single acting slip positioned on a mandrel on opposite sides of a packing element and a setting cylinder. The single acting slip is designed to resist forces acting on the mandrel in one direction. Setting forces generated by the setting cylinder are coupled to the mandrel through a releasing sleeve. When the releasing sleeve is decoupled from the mandrel, the slip setting forces on both slips and the packing element are released and the packer can be retrieved from a well. In a preferred form, the releasing sleeve may be decoupled from the mandrel by multiple means.