Sand/Erosion Velocity Calculator

Erosional velocity is the maximum allowable fluid velocity in a pipe above which erosion-corrosion damage is expected. Per API RP 14E, it is calculated as Ve = C / sqrt(rho_mix), where C is an empirical constant (typically 100-150) and rho_mix is the fluid mixture density in lb/ft3. Operating above this velocity accelerates material loss from pipe walls.

The C factor depends on service conditions: C = 100 for continuous service with solids present, C = 125 for intermittent service or clean fluids, and C = 150-200 for corrosion-resistant alloys (CRA) or solid-free service. Higher C values allow higher velocities. For sand-producing wells, C = 100 is conservative.

DNV-RP-O501 provides a more detailed erosion model that accounts for sand particle size, sand rate, pipe geometry, material hardness, and impact angle. It calculates actual metal loss rate (mm/yr) rather than just a velocity limit. This allows engineers to predict pipe wall thinning and remaining service life, making it more suitable for sand management programs.

The velocity ratio (actual velocity / erosional velocity) should be below 1.0 to prevent erosion damage. Best practice is to keep the ratio below 0.7 for long-term continuous service. Ratios between 0.7 and 1.0 require monitoring, and ratios above 1.0 indicate erosion risk requiring design changes such as larger pipe, lower flow rate, or erosion-resistant materials.