Advanced Engineering

Explosive Decompression Materials

Theory of Explosive Decompression:

Explosive Decompression (ED), also referred to as Rapid Gas Decompression (RGD), is a failure mechanism of elastomer seals that is due to the rapid decompression of a gaseous media. When elastomer seals are exposed to high-pressure gas for a prolonged period the gas permeates into the seal material. When the external pressure is reduced, the gas which is dissolved within the seal material comes out of solution to form micro bubbles. As the gas expands, it may permeate out of the seal material. However, if the rate of decompression (and hence expansion) is high, gas which is trapped within the seal can cause fissuring and result in seal failure.

Elastomer seals affected by explosive decompression.

We provide a peroxide-cured, explosive decompression resistant HNBR compounds. They provide good chemical resistance to sour gas (H2S), methanol (CH3OH), crude oil, lubricating agents, and oil additives, with superior resistance to carbon dioxide, water, drilling mud and amine corrosion inhibitors.

A range of elite materials has been specifically developed for Explosive Decompression (ED) resistance in downhole, surface and subsea oilfield equipment. The high mechanical strength and abrasion resistance makes them particularly suitable at dynamic applications.

Explosive Decompression Standards:

There are a number of international standards for testing elastomer materials in ED conditions, they include:

• NORSOK Specification M-710 Rev.2 Section 7.3/Annex B: “Qualification of non-metallic Sealing Materials and Manufacturers - Resistance to rapid gas decompression (RGD)”

• TOTAL General Specification GS PVV 142 Appendix 8 “Elastomer O-ring Seals Explosion Decompression Type Testing Procedure”

• NACE TM0297 “Effects of High-Temperature, High-Pressure Carbon Dioxide Decompression on Elastomeric Materials”.