MAASP Calculator
Calculate Maximum Allowable Annular Surface Pressure for well control operations. MAASP is the maximum pressure that can be applied at surface without fracturing the weakest exposed formation.
Input Parameters
Weakest exposed formation depth
From LOT/FIT results
Optional: subtract safety margin
MAASP = (FG - MW × 0.052) × Shoe TVD
where FG = fracture gradient (psi/ft), MW = mud weight (ppg)
MAASP
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psi
Fracture Pressure at Shoe
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psi
Hydrostatic at Shoe
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psi
Equivalent Mud Weight at Fracture
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ppg — max mud weight before fracture at shoe
How this was calculated
MAASP: The maximum surface pressure that can be applied to the annulus without exceeding the fracture pressure at the weakest exposed formation (typically the casing shoe).
Critical for: Well control procedures, BOP operations, managed pressure drilling, and kick handling decisions.
Note: MAASP decreases as mud weight increases. At the point where hydrostatic pressure equals fracture pressure, MAASP = 0.
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Book a free strategy call →Understanding MAASP
Maximum Allowable Annular Surface Pressure (MAASP) is one of the most critical parameters in well control. It represents the maximum pressure that can be applied at the wellhead without fracturing the weakest exposed formation, which is typically at the casing shoe. Exceeding MAASP during a kick can result in underground blowout or lost circulation, both of which significantly complicate the well control situation.
MAASP should be recalculated every time mud weight changes, after each LOT/FIT, and when the hole is deepened past a casing shoe. Built by Groundwork Analytics.