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
Slugging
- 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)
Applications
- Well testing, well cleanout, underbalanced drilling, produced solids, proppant flow back
Utilities
- Flush screen (clean water any source at 50-100 psi)
Consumables
- 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.
References:
- 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.
