Selecting the correct sealing material according to different working conditions is an important factor to ensure the safe and efficient operation of the equipment. There are many types of liquids that need to be controlled in the petrochemical and natural gas industry, such as aromatic hydrocarbons, rust inhibitors, acid gas, drilling fluid, seawater, carbon dioxide, hydrogen sulfide, etc.
And these media are often mixed together and have the characteristics of high temperature and high pressure. Therefore, the sealing materials used are required to have good quality and good chemical compatibility.
A variety of sealing materials are used in the oil and gas industry, and these sealing materials can basically be divided into the following four categories:
1. Elastomers (rubbers)
2. Plastic elastomer (polyurethane)
3. Polytetrafluoroethylene and its compounds
The developed high-quality plastic elastomer material - polyurethane, although polyurethane is limited in high temperature applications, polyurethane has excellent anti-wear and anti-extrusion properties, and it has excellent compatibility with petroleum industry fluids including acid gases.
In addition to rubber, polyurethane and tetrafluoroethylene and plastic materials, spring seals are also required under certain working conditions, and there are special requirements for spring materials. Available in NACE MR-0175 compliant spring materials that are compatible with sour environments.
Elastomeric materials are by far the most widely used sealing materials in oilfield production. It is divided into many kinds. Commonly used NBR (nitrile butadiene rubber) or HNBR (hydrogenated nitrile butadiene rubber). Fluorine rubber (FKM/FPM, TFE/P, FFKM) has high chemical stability, and its chemical stability increases with the increase of fluorine content in the material.
Under certain conditions, elastomeric sealing materials alone cannot provide a fully effective seal. In this case, other high-quality sealing materials such as PTFE (polytetrafluoroethylene) or PEEK (polyetheretherketone) can be selected to be used together with elastomer materials to achieve higher anti-extrusion performance sealing effect, sometimes PTFE/ PEEK can even be used alone as a sealing material.