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Maximum Allowable Annular Surface Pressure from Shoe EMW Calculator

MAASP=(MWmax−MW)0.052TVDshoeMAASP=(MW_{max}-MW)0.052TVD_{shoe}

Enter shoe EMW, current mud weight, and shoe TVD. The calculator returns the annular surface pressure margin in psi.

Tabular solver

Inputs

Defaults provide a quick field-unit example for the equation.

3 variables

Calculation runs locally with the shared TypeScript engine.

Formula reference

Maximum allowable annular surface pressure estimates the casing-shoe pressure limit by comparing shoe equivalent mud weight with current mud hydrostatic pressure.

View formula, units, and source

Assumptions

  • Shoe strength is represented by equivalent mud weight at shoe depth.
  • Current mud weight is uniform to the shoe.
  • The calculation uses US field units.

Common mistakes

  • Using bit depth instead of shoe depth.
  • Confusing MAASP with allowable casing pressure at another depth.
  • Ignoring safety factors required by the well program.