Sandstone Mud Acid (HF/HCl) Stoichiometry Calculator

Calculate stoichiometric consumption of hydrofluoric (HF) and hydrochloric (HCl) acid blends for quartz, feldspar, and clay dissolution in sandstone reservoirs.

Mineralogy & Acid Formulation

Mud Acid Formulation:

Formation Clay Content (% wt): Kaolinite, Illite, Smectite

Feldspar Content (% wt):

Carbonate Content (% wt): Calcite / Siderite / Ankerite

Reservoir Temperature (°F):

Treatment Interval Height (ft):

Acid Sequence & Preflush Demands

Recommended Preflush Volume:

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Main Mud Acid Volume:

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Secondary Precipitation Risk:

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Clay Dissolution Ratio:

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HCl Spent on Carbonates:

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Postflush Overdisplacement:

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Frequently Asked Questions

Why is an HCl preflush always pumped before Mud Acid in sandstones?

The HCl preflush dissolves all calcite, siderite, and dolomite in the near-wellbore region and displaces formation water containing sodium and potassium ions. This prevents catastrophic in-situ precipitation of calcium fluoride (CaF2) and alkali fluosilicates (Na2SiF6 / K2SiF6) when HF enters the rock.

What is the purpose of the postflush stage?

The postflush (typically 3% to 5% ammonium chloride NH4Cl with mutual solvent) displaces spent HF reaction products at least 3 to 5 feet away from the critical near-wellbore area and strips oil off rock surfaces to restore water-wet conditions.