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Linked Drilling Hydraulics Calculator

Link hydrostatic pressure, measured annular pressure loss, ECD, annular velocity and volume using one consistent set of drilling inputs.

Inputs

Results

Calculate to view linked results. Default values are examples, not recommended operating inputs.

Learn, compare and practice

Worked explanations, controlled studies and printable exercises connected to this calculation.

Same flow rate different hole sizes a synthetic hydraulics studyDrilling hydraulics practice problems and answer sheet

Calculation sequence

  1. Hydrostatic pressure is calculated from mud weight and true vertical depth. Annular volume instead uses the measured length of the selected uniform interval; the two depth inputs are intentionally separate.
  2. Add the supplied annular friction pressure to hydrostatic pressure. ECD expresses that combined pressure as an equivalent density at the same TVD; surface backpressure is not included.
  3. Velocity comes from the flow rate and annular area. The flow sweep changes velocity only: friction loss and ECD are not scaled without a rheology and pressure-loss model.

Worked check

With 10 ppg at 10,000 ft TVD, hydrostatic pressure is 5,200 psi. Adding 500 psi of annular friction gives 5,700 psi and ECD 10.961538 ppg. With no friction, ECD equals mud weight; with zero flow, calculated mean annular velocity is zero.

Synthetic examples for reproducibility, not measured field results.

Assumptions and limitations

  • One constant-density, uniform annular section. No cuttings loading, eccentricity, compressibility or temperature-density profile is modelled.
  • Enter annular friction loss, not total standpipe pressure or pipe-and-bit loss. This does not estimate friction from flow rate.
  • This is a consistency check, not a well-control procedure, hole-cleaning verdict or pressure-window approval.

Implemented equations

Hydrostatic Pressure from Mud Weight

HP=0.052MW⋅TVDHP = 0.052 MW \cdot TVD

Equivalent Circulating Density

ECD=MW+ΔPa0.052TVDECD = MW + \frac{\Delta P_a}{0.052TVD}

Velocity of Fluid in Annulus

va=Q2.448(Do2−Dp2)v_a = \frac{Q}{2.448(D_o^2-D_p^2)}

Annular Volume Capacity of Pipe

Va=0.7854(Dh2−Do2)L808.5V_a=\frac{0.7854(D_h^2-D_o^2)L}{808.5}

Sources and maintenance

Published by PetroCalcHub Team. Implementation and source checks: . This does not claim independent expert review.

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Related tools and references

ECD calculatorHydrostatic pressure calculatorDrilling hydraulics guide