The MPas formation packer has an elastomeric element with a composite structure set mechanically by shifting a balance sleeve, allowing wellbore hydrostatic pressure to act against an atmospheric chamber and applying setting force to the non-inflatable element. The element is then mechanically locked, eliminating the requirement of the wellbore fluid to maintain the set. Wellbore hydrostatic pressure will continue to apply a setting force on the element throughout the packer's life, which will compensate for the movement of the formation and allow for additional setting force to be applied at any time. Additional setting force can be attained by applying additional pressure with a cup tool or by applying pressure to the entire casing string if applicable. The MPas packer is generally run in the liner string between screens, slotted casing, or gravel-packed sections to isolate production intervals. It can also be used to isolate the openhole/liner annulus in openhole completions in conjunction with stage cementing equipment. The MPas packer can be run single or stacked in multiples to increase seal length.