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Application notes
Pressure Transmitters Help Make Extracting Oil and Gas Cleaner and Greener
Multifaceted Pressure Transmitters Support Plunger Lift Systems
Pressure Transmitters for Wellhead Platforms
Oil and natural gas extraction has traditionally been somewhat messy. Companies in this business are often eager to identify ways to make their processes kinder to the environment. In today’s green-conscious world, that has taken on added importance.
Natural-gas extraction platforms have been one of those problematic settings, mainly because of wellhead blowdown. This technique was developed to clear liquid buildup in the production tubes of gas wells, thus restoring the well’s efficiency. In a blowdown, the wellhead is closed so the pressure within the system will build. When high pressure is reached, the wellhead is opened. Natural gas purges the system of liquid, freeing up the system blockage and discharging both waste liquid and production gas into the surrounding environment.
Plunger-lift systems are a clean, efficient, and cost-effective alternative to well blowdown. Such systems make use of natural pressure buildup in a well line to help clear liquid blockages, thus eliminating the need to release tainted liquid and natural gas into the environment. Pressure transmitters play a key role in pressure measurement at every step of plunger lift operations.Hazardous-area pressure transmitters and explosion proof pressure transmitters are commonly used for this type application in the oil and gas industry.
How a plunger lift system works on a wellhead platform:
- The plunger rests at the top of the wellhead’s lubricator. In this resting state, fluids will build up in the wellhead’s production tube, creating back pressure and slowing gas production.
- The wellhead closes automatically when liquid sufficiently slows gas production. The plunger then falls to the bore hole, at the production tube’s bottom. Pressure from the production gas builds in the wellhead tubing and casing.
- The pressure gets released, opening the wellhead, under control of an onboard computer system, and sending the plunger and accumulated liquid to the wellhead’s top.
- The plunger is held at the top of the wellhead in its lubricator, permitting liquids to escape the lift system via the upper lubricator outlet. These liquids go into a storage unit
- Gases leave the lift system through the lower lubricator unit. The gases are sent to the sales line.
- The plunger remains at the top of the lubricator until water ingress provides sufficient back pressure for it to drop and for the plunger-lift cycle to repeat itself.
Pressure Transmitters for Casing and Tubing Applications
Pressure transmitters provide accurate pressure measurements to support operations of the plunger lift system and relay pressure measurements in a variety of casing and tubing applications.
Pressure transmitters for casing and tubing applications include:
- Bore hole pressure
- Casing tube pressure
- Flow rate monitoring
- Lower lubricator outlet pressure
- Production tube pressure
- Upper lubricator outlet pressure
Keep in mind that oil and gas extraction requires the use of pressure transmitters certified for Class I Division I and/or Class I Division II hazard areas. WIKA E-10 and E-11 hazardous area pressure transmitters meet such criteria and are also designed especially upstream oil and gas extraction. In addition, these are certified explosion proof pressure transmitters.
What to Consider in Selecting Pressure Transmitters
- Absolute or gauge pressure measurement
- Accuracy and error ratios
- Cable or flying lead pressure transmitter wiring
- Class I Division I or Class I Division II hazardous area pressure transmitter
- Conduit or non-conduit pressure transmitter
- Conduit wiring protection – required in hazardous settings
- Electromagnetic interference (EMI)
- Intrinsically safe, non-incendiary, explosion proof pressure transmitter
- Media compatibility
- Moisture resistance
- Radio-frequency interference (RFI)
- Standard or flush diaphragm
- Turbulent, laminar or static-fluid
- Vertical or horizontal mounting
- Vibration resistance