Directional perforation erosion

§10.1 — Full directional erosion (D_u, D_s, D_d, C_d) with Bell (1995) initial diameter, calibration knobs, time-series, and a velocity sensitivity sweep.

Bell (1995) gun geometry

Gun OD(in)Wellbore ID(in)Phasing(°)

Clearance0.563 in

Baseline D0.405 in

Phasing factor0.660

Effective initial D0.267 in

Slurry & kinematics

Concentration(kg/m³)v_perf(m/s)v_well(m/s)Duration(min)

Velocity sweep

v_perf min(m/s)v_perf max(m/s)Steps

Calibration (eq 8-25)

α (m²·s/kg)β (m·s/kg)γ (axial)Cd₀Cd_max

D_u final0.3040 in

D_s final0.3040 in

D_d final0.3122 in

D_eq final0.3061 in

C_d final0.891

Downhole Ballistics Simulator

Directional perforation erosion

Bell (1995) gun geometry

Slurry & kinematics

Velocity sweep

Calibration (eq 8-25)

Diameter trajectory

Discharge coefficient

Velocity sweep — final D_eq & C_d