Filteration & Separator Skid

1. Stage 1: Inlet & Primary Separation (Gas & Free Liquids)
⦁ Purpose: Initial separation of gas and bulk liquids.
⦁ Process:
⦁ Well fluids enter the skid through an inlet diverter or cyclonic inlet, which reduces flow velocity to allow initial separation.
⦁ Gas rises due to low density and exits through a gas outlet for further treatment (e.g., flare, compression, or sales).
⦁ A mist extractor removes entrained liquid droplets from the gas stream.
⦁ Gas is sent to flare, fuel gas, or compression.
⦁ Liquids (oil, water, and sand) settle and flow into the next stage.

2. Stage 2: Sand & Solids Removal
⦁ Purpose: Remove abrasive solids (sand, silt, scale) to protect downstream equipment.
⦁ Process:
⦁ Liquids pass through a sand trap or desander (hydrocyclone or gravity-based).
⦁ Centrifugal force causes heavier sand/solids to spiral downward and settle at the bottom.
⦁ Sand & solids settle and are discharged via a sludge outlet (manual or automated).
⦁ The remaining liquid (oil & water) moves to the next stage.

3. Stage 3: Oil-Water Separation (Coalescing or Gravity-Based)
⦁ Purpose: Separate oil from water.
⦁ Process:
⦁ The liquid enters a coalescer or gravity separator or FWKO (Free Water Knockout). (e.g., API separator, CPI plate pack).
 Gravity separation occurs: Oil (lighter) floats on top, water (heavier) settles at the bottom.
 A coalescer pack may accelerate the oil droplet separation.
 Level controllers regulate oil and water interface levels.
 Oil is skimmed and flows out through the oil outlet.
 Water exits from the bottom to water polishing stage.

4. Stage 4: Polishing (Water Treatment)
⦁ Purpose: Further clean water to meet disposal/reuse standards.
⦁ Process:
⦁ Water passes through a filter (media, cartridge, or membrane) or flotation unit (DAF – Dissolved Air Flotation), hydrocyclones, Induced Gas Flotation (IGF), or a Compact Flotation Unit (CFU).
⦁ Fine oil droplets are coalesced and floated to the top or spun out.
⦁ Remaining fine solids are removed.
⦁ Treated water is discharged or reinjected.

Key Components of the Skid:
⦁ Vessels: Separators, coalescers, sand traps.
⦁ Pumps & Controls: Transfer pumps, level sensors, automated valves.
⦁ Piping & Valves: Flow control between stages.
⦁ Instrumentation: Pressure gauges, temperature sensors, flow meters.
⦁ Safety Systems: Pressure relief valves, flame arrestors (if gas is present).
⦁ Level transmitters (oil/water interface)
⦁ Pressure transmitters
⦁ Temperature sensors
⦁ Automated valves and PLC control