Casing Vapor Recovery
The main objectives of a casing vapor recovery system are to
- Minimize back pressure on wells
- Minimize discharge of hydrocarbons and other fugitive gasses to the environment
- Recovery of heat from casing gasses
- Collect hydrocarbon condensate in the gas streams for addition to the sales stream.
In oil fields that are on steam-flood or steam lift, there is an overt effort to maintain a low back pressure on the producing formation. This is done by keeping the wells "pumped off" and by lowering the pressure in the annulus.
In a system that has steam injected, steam vapor often times will come up through the annulus and will condense in the CVR system.
A CVR System consists of:
- collection branch and trunk lines
- Heat exchangers or condensers
- Vapor-Liquid Separators
- Water / Oil Separation
- Incineration of non-condensible gasses
The condition that occurs when heat is absorbed by the surface of a liquid and it changes to vapor.
Liquid Vapor Mixture
Liquid vapor mixture (called a two-phase) of the same substance can coexist at the same pressure and temperature.
Saturated vapor is a vapor at a temperature of the boiling point on the verge of condensing.
Superheated vapor is when vapor has absorbed more heat than is needed to vaporize. It will not condense when small amounts of heat is removed.
Water Vapor Diffusion
The process by which water vapor spreads or moves through permeable materials caused by a difference in water vapor pressure.