In downhole operation, the oil & gas industry needs a reliable methodology to develop an operation envelope for elastomer seals used in various tools. In most cases, the operation envelope estimate relies on laboratory life prediction methods. The conventional life prediction methods based on industry standards, ISO 23936-2:2011(E) and API TR-6J, are designed for “materials selection/screening” using the Arrhenius equation. However, the conventional mechanism has limitation in predicting actual performance of elastomer seals. Hence, there is a need for a new methodology which can serve many operators and regulators with reliable approach in life prediction for various projects in the oil & gas industry. The objective of this paper is to develop an operation envelop based upon the lifetime prediction method. The lifetime prediction method covers viscoelasticity properties and chemical degradation combined with experimental/FEA simulation approach. The paper addresses the effect of compression on the degradation of the Fluoroelastomer seal. The paper shows how the laboratory findings combined with FEA modeling can be used to develop a reliable operation envelope for the elastomer sealing application in the oil & gas industry.