Proppant convection & flowback
§14 of the ResFrac formulation. Two coupled post-treatment phenomena: density-driven convection of the slurry inside the fracture (Rayleigh instability of dense over light layers), and the dynamic flowback of proppant once production resumes after shut-in. Use the calibration page to fit cell amplitude or RZ exponent against measured data.
Slickwater carrier, 40/70 sand at 0.15 vol, 8 bpm/cluster, 250k lb stage, 6,000 psi closure.
§14.1–14.3 Gravitational convection
§8.8 Gravitational convection (Ra = 394808652 / Ra* = 500)
Thresholds from ResFrac §8.8 calibration: Ra* = 500 (slot/Hele-Shaw critical). Horizontal advection damps cells when Pe = U/u_cell > 5 (current Pe = 1.20).
Vertical bands use the active Ra/Ra* edges (0.50, 1.00, 5.00). Horizontal dashed line is the Pe demotion cutoff (5.00); the amber tint above it flags where strong horizontal advection knocks "convecting" / "vigorous" back to "marginal". Slide along the dotted guides to see how shifting Ra alone (vertical) or Pe alone (horizontal) flips the regime.
Δρ = (ρ_s − ρ_f)·c drives buoyancy in a slot of width w. Cell velocity = min(√(g·Δρ·w/ρ_f), g·Δρ·w²/12μ). Strong horizontal advection (Pe ≫ 1) suppresses cells; vigorous regimes redistribute proppant and degrade the bed-slumping equilibrium predicted above.
Evolving cells (t = 0 s · 20 cells · mean intensity 0%)
§14.4–14.6 Post-shut-in flowback
- Shut-in hardened k_trap by 65% before production began.
- Significant flowback: 100.0% of placed mass returned despite consolidation.
Paste measured surface returns since start of production. The fitter searches all four free parameters (256-sample Halton scan + per-axis golden-section refinement) and returns the parameter set that minimizes RMSE against your data. Use the resulting values in the live flowback panel above.
CSV columns: t_prod_hr, value