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Wellhead Screen-Filter – Operability and Application (post B-FSM-108)

This post lists the operating boundaries and applications of the wellhead screen-filter. It is a well service tool used for testing, cleanout, and flowback operations.

Operating Boundaries

Pressure Drop

  • No minimum
  • Maximum determined by limiting design velocity or screen burst pressure
  • Will impose back pressure on artificial lift wells

Flow Conditions

  • Operation from 0-100% GVF
  • Turndown: infinite from maximum pressure drop


  • Must stay within pressure drop range

Fluid Viscosity

  • Avoid oil with high liquid viscosity (>100 cP)

Particle Size

  • Capture size determined by mesh (minimum recommended is 100 mesh)
  • No maximum size other than what can fit through inlet nozzle

Particle Concentration

  • No maximum for separation mechanism
  • Accumulation volume and rate of isolation/discharge will be limiting factory at high solids concentration

Application and Operations

Installation Location

  • Pre-choke (API)


  • Well testing, well cleanout, underbalanced drilling, produced solids, proppant flow back


  • Flush screen (clean water any source at 50-100 psi)


  • Screen replacement and o-rings

Process Connections

  • Four standard: inlet, clean fluid outlet, solids discharge, and flush

Effects of Chemicals and FOD

Natural and Artificial Chemicals Present

  • Bad Chemicals – anything that increases viscosity or forms a sticky goo
  • Good Chemicals – anything that decreases viscosity or breaks sticky goo
  • Scale may be a problem if forming on aperture openings
  • Flocculants will not work to “grow” particle size because shear forces break flocs (especially at these large mesh sizes)

Foreign Object or Debris (FOD)

  • Remove any deformable foreign material that will blind or block screen and is hard to clean
  • Thread seal (pipe) tape, paper, soft rubber, gloves, etc.


  1. Rawlins, C.H., “Sand Management Methodologies for Sustained Facilities Operations”, Oil & Gas Facilities, Vol. 2, No. 5, October 2013, pp. 27-34. https://doi.org/10.2118/1013-0027-OGF

Next week I will cover WSF mechanical design.

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