Well volumes & circulation time
Annular and string volumes section by section, then the strokes and the minutes to bottoms-up and to a full circulation.
Drilling
ECD & bottom-hole circulating pressure
Annular pressure loss, flow regime and the equivalent circulating density the formation actually sees while the pumps are running.
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How it is calculated
- Bingham plastic, in the field form: laminar gradient = PV·V/(60000·(Dh−Dp)²) + YP/(200·(Dh−Dp)).
- Critical velocity decides the regime; above it the turbulent correlation ρ⁰·⁸Q¹·⁸PV⁰·²/(1396(Dh−Dp)³(Dh+Dp)¹·⁸) is used instead.
- ECD = effective mud weight + annular loss / (0.052 · TVD). Cuttings loading is applied as a volume-weighted density with 2.6 SG rock.
- If you enter Fann readings, PV = θ600 − θ300 and YP = θ300 − PV.
Standards it speaks
Where this stops being true
Bingham plastic over-predicts annular loss for a shear-thinning polymer mud, sometimes by a factor of two or three — a power-law or Herschel–Bulkley model would give a lower and more realistic number, and this tool deliberately does not guess at one. It also assumes one uniform annular geometry, an isothermal column, and no pipe rotation or eccentricity, each of which moves the answer by a meaningful amount. Treat it as a bound and a sanity check, never as a substitute for a hydraulics simulator on a narrow-margin well.
The capability that automates this
- DR-06Real-Time Torque, Drag & HydraulicsCompares what the string should weigh and how hard the pumps should work against what is actually measured, and flags the gap.
- DR-15Managed Pressure Drilling SupportHelps hold bottom-hole pressure inside a narrow window by predicting what the choke needs to do before the transient arrives.
Related tools
Bit hydraulics & nozzle selection
Total flow area, nozzle pressure drop, HSI and jet impact force — plus the nozzle size that would put the optimum share of pump pressure at the bit.
Directional survey — minimum curvature
Paste MD, inclination and azimuth and get TVD, northings, eastings, dogleg severity, vertical section and closure — with the well path drawn.
Kill sheet — driller's method
Kill mud weight, initial and final circulating pressure and the step-down schedule, for rehearsal and for checking a sheet that has already been worked.
Training aid