Oil & Gas Sealing: Downhole, BOP and Sour Gas
HNBR and FKM O-rings engineered for HPHT wells, sour service and blowout preventer sealing.
Oil and gas sealing is one of the most punishing environments for elastomers. Downhole tools encounter high pressure, high temperature (HPHT), hydrogen sulfide (H2S), CO2, and aromatic hydrocarbons. Blowout preventers (BOP) and wellhead equipment demand seals that must not fail under emergency pressure conditions. We supply NACE MR0175 / ISO 15156 compliant HNBR and high-fluorine FKM O-rings for sour gas and HPHT applications. These compounds are formulated to resist rapid gas decompression (RGD), thermal aging, and chemical attack while maintaining the extrusion resistance needed for 300+ bar pressures.
Application Requirements
Design Tips
- 1.Use 90 Shore A hardness for all high-pressure oilfield seals to maximise extrusion resistance
- 2.Install PTFE backup rings for pressures above 200 bar or clearance gaps greater than 0.10 mm
- 3.Specify RGD-resistant HNBR for gas wells to prevent blistering during decompression
- 4.Allow for thermal expansion in HPHT grooves — keep groove fill below 80%
- 5.Use bronze-filled PTFE backup rings for the highest extrusion resistance in BOP seals
Common Sizes
| Size | Typical Use |
|---|---|
| AS568-325 to AS568-395 | large wellhead and BOP seals |
| AS568-210 to AS568-284 | downhole tool and valve seals |
| Custom sizes for packer elements and mandrel seals | General application |
| Vulcanised large-diameter rings for tank manways and access hatches | General application |
Frequently Asked Questions
What does NACE MR0175 mean?
NACE MR0175 / ISO 15156 is the international standard for materials used in H2S-containing (sour) oil and gas production environments. It defines hardness limits and material requirements to prevent sulfide stress cracking.
Is HNBR or FKM better for sour gas?
HNBR is generally preferred for sour gas (H2S) service due to its superior resistance to hydrogen sulfide. FKM can be used in sour gas at moderate temperatures but HNBR is the safer choice for high H2S concentrations.
What is rapid gas decompression (RGD) resistance?
RGD resistance is the ability of an elastomer to withstand blistering and cracking when high-pressure gas diffuses into the seal and then decompresses rapidly. Special HNBR compounds are formulated to resist this failure mode in gas wells.
Can you supply material certificates for oilfield O-rings?
Yes. We provide NACE compliance letters, hardness test reports, batch traceability records, and third-party RGD test reports on request.
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