Explosive Decompression (ED), also known as Rapid Gas Decompression (RGD), is structural failure in the form of blistering, internal cracking andfor splitting caused when the gas pressure to which the seal is exposed is reduced faster than the gas can diffuse out of the part. This causes internal stresses in the part that can exceed the physical strength limits of the elastomer.
This paper presents the results of ED testing performed in our laboratory at the European Technical Centre (ETC) in Meyrin, Switzerland, as a continuation of the work presented by Robert E. Fuller at the Oilfield Engineering with Polymers 2006 conference in London in March 2006. The latter discussed the suitability of fluorinated elastomers for the oil and gas field by comparing three Viton@ fluoroelastomers made with Advanced Polymer Architecture (APA) to conventional FKM and FEPM polymers. Compound suitability in High Pressure High Temperature (HPHT) wells was discussed. We now report ED data obtained using samples of the compounds in the 2006 paper together with our observations and conclusions regarding the testing procedure and the compound behavior. FKM polymers with fluorine levels ranging from 66 to 70% have been evaluated in different formulations and their ED resistance compared to industry standard FKM and TFEXP compounds. Testing was performed in a 100% C02 environment using internally developed laboratory equipment with the primary intent of developing a means of comparative material evaluation as opposed to providing data directly correlatable with performance in service. Pressures and temperatures ranging from 5 to 15 MPa and from room temperature to 200C,respectively, were used to rate the compounds according to their ED performance.