A three-phase separator is a critical piece of equipment in the oil & gas production process, used to efficiently separate the oil, gas and water produced at the wellhead. It is typically deployed in oil & gas gathering and transportation stations, testing stations, or early production facilities.
Basic principle
The three-phase separator operates based on density differences and gravity settling.
Gas, with the lowest density, collects at the top of the separator and is discharged through the gas outlet.
Crude oil, with a medium density, floats on the water surface and is discharged through the oil outlet.
Water, with the highest density, settles at the bottom and is discharged through the water outlet.
Internal baffles, coalescing devices, and liquid level control systems can enhance gas-liquid and oil-water separation.
Main types
Horizontal three-phase separators
Commonly used for treating well streams with high water content. They offer a large contact area and long resistance time, resulting in superior oi-water separation.
Vertical three-phase separators
Occupy a small footprint and are suitable for applications with limited space. They offer excellent gas-liquid separation, but are relatively weak at separating oil and water.
Spherical separators
Used for high-pressure wells, they offer uniform force distribution and strong pressure resistance. Generally used for testing and special applications.
Internal structure
Inlet separator: Reduces fluid kinetic energy and provides initial gas-liquid separation.
Gas separation section: Gas rises, while an entrainment remover removes entrained liquid droplets.
Oil-water separation section: Utilizes gravity and baffles to separate the oil and water.
Liquid level controller: Maintains a stable oil-water interface to prevent cross-entrainment.
Applications
Single well testing: Measure the production capacity of oil, gas and water.
Gathering station processing: Perform preliminary treatment of mixed well streams to reduce the burden on subsequent processes.
Early production facilities(EPS):Used during test production on offshore platforms and onshore.
