Weighting up, diluting and blending fluids
How much weighting material (barite, hematite, calcium carbonate), water or another fluid to add to bring the mud to the required density, and the final volume.
V_a = V_1 · (ρ_2 − ρ_1) / (ρ_a − ρ_2)m_a = ρ_a · V_aV_2 = V_1 + V_aVolumes of insoluble weighting materials and of water add up; dissolving salts shrinks the volume, so take brine densities from tables. The required density must lie between those of the mud and of the additive. The Kazakhstan industrial safety rules (item 85-7) require weighting up while circulating the whole volume, not in separate batches.
Source: Ideal mixing mass balance: Bourgeois et al., Applied Drilling Engineering (SPE, 1986), ch. 2; weighting material densities per API Spec 13A
Inputs
You can change a field's unit: the value is converted to the formula's units automatically.
Barite 4.2 g/cm³, hematite 5.05, calcium carbonate 2.7, water 1.0; when blending two fluids, the density of the second one.
Unit converter for this formulaLiquid volume · Density and °API · Mass
- m³1
- 10³ m³0.001
- 10⁶ m³1·10⁻⁶
- L1,000
- bbl6.28981
- Mbbl0.00628981
- MMbbl6.28981·10⁻⁶
- ft³35.3147
- US gal264.172
- V_a — Volume added–
- V_2 — Final volume–
More in Pressures and drilling fluid
Pressure of a column of drilling or kill fluid at a true vertical depth, and its gradient (equivalent density).
Kill mud weight from the shut-in drill pipe pressure, and the initial and final circulating pressures for the driller's and the wait-and-weight methods.
Equivalent density of the pore pressure and the mud weight that keeps the hydrostatic pressure above it by the margin of the Kazakhstan industrial safety rules (item 85-2), with the depth-dependent cap on the overbalance.
The density equivalent to the bottomhole (or shoe) pressure while circulating: the static mud column plus the annular friction loss above that point.
Fracture (leak-off) equivalent density and pressure at the shoe from a LOT or FIT, and the maximum allowable annular surface pressure (MAASP) for the current mud weight.
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.