Cement slurry: density, yield, cement and water
Slurry density and yield from the water-cement ratio, and the dry cement mass and mix water volume for a given slurry volume.
Y = 1/ρ_c + m/ρ_wρ_sl = (1 + m) / YM = V / Y · (1 + k)V_w = m · V / (Y · ρ_w)Cement and water volumes add up (neat slurry, no air). Additives (bentonite, extenders, weighting agents) enter with their absolute volumes from the lab recipe. Water is for the slurry volume without the loss allowance; a sack is 94 lb (42.64 kg), as in API.
Source: API Spec 10A (water ratios of classes G and H); GOST 1581 (oil-well Portland cements); Nelson, Guillot, Well Cementing (Schlumberger, 2006)
Inputs
You can change a field's unit: the value is converted to the formula's units automatically.
Mass of water per mass of cement: 0.44 for class G, 0.38 for class H, 0.50 for Russian PTsT I-50 and I-100 cements.
Portland cement: 3.10–3.20 g/cm³.
Handling and mixing losses, per the job procedures.
Unit converter for this formulaDensity and °API · Liquid volume · Mass · Fraction and percent
- kg/m³850
- g/cm³0.85
- t/m³0.85
- rel. (water 4 °C)0.850024
- lb/ft³53.0638
- lb/gal (ppg)7.09359
- SG (60/60 °F)0.850837
- °API34.8068
°API and SG refer to the density at 60 °F (15.6 °C) relative to water at 60 °F, relative density to water at 4 °C. The oil's thermal expansion between the measurement temperatures is not included. °API = 141.5 / SG − 131.5.
- Y — Slurry yield per tonne of cement–m³/t
- q_c — Cement per m³ of slurry–t/m³
- M — Dry cement mass–
- V_w — Mix water volume–
- Y_sk — Yield per 94-lb sack–ft³/sk
- w_sk — Mix water per 94-lb sack–gal/sk
More in Cementing
Slurry volume for a single-stage casing job: the open-hole annulus with excess, the overlap with the previous casing, the shoe track and the rat hole, plus the displacement volume down to the float collar.
Slurry volume for a plug of a given length, the slurry height with the pipe in the hole, the spacer volume behind the cement that balances the columns, and the displacement volume.
Results are engineering estimates from standard formulas; for design decisions check them against the codes, project documents and specialists' calculations. The formulas carried over from the original set are unchanged, and their errors are described in the notes.