Live Engineering Dashboard

Well Testing Toolbox

Interactive Tools

Engineering calculators and conversion utilities for field work.

General Well Testing Calculations

Gas Velocity & Volume (1)

Gas Velocity ($V$):

$$V = \frac{2122 \times B_g \times Q_{mscf}}{d^2}$$ Where $B_g = 0.02833 \frac{Z \cdot T}{P}$

Gas Volume (1)

Method 1 (Velocity-Based):
$$Q = \frac{V \times d^2}{2122 \times B_g}$$

Gas Volume (2)

Method 2 (Choke/Pressure-Based):
$$Q = P_{psia} \times \left(\frac{d_{64}}{64}\right)^2 \times 24$$

Twin Choke Factor

Equivalent Twin Choke Size:

$$D_{eq} = \sqrt{d_1^2 + d_2^2}$$

OIL VOLUME

$$Q_{oil} = \frac{P \times D^{1.89}}{435 \times (GOR/1000)^{0.546}}$$

CORRECTED S.G. @ 60°F

S.G. & API Conversions

API Gravity Conversion:

$$API = \frac{141.5}{SG @ 60^\circ F} - 131.5$$

Shrinkage Factor (Standing-Based Table Formula)

$$Bo = 0.9759 + 0.00012 \times F^{1.2}$$ Shrinkage = $1 / Bo$

Well Testing Core Formulas

Gas Velocity ($V$):

$$V = \frac{2122 \times B_g \times Q_{mscf}}{d^2}$$ Where $B_g = 0.02833 \frac{Z \cdot T}{P}$
Method 2 (Choke/Pressure-Based):
$$Q = P_{psia} \times \left(\frac{d_{64}}{64}\right)^2 \times 24$$
Method 1 (Velocity-Based):
$$Q = \frac{V \times d^2}{2122 \times B_g}$$

API Gravity Conversion:

$$API = \frac{141.5}{SG @ 60^\circ F} - 131.5$$

Equivalent Twin Choke Size:

$$D_{eq} = \sqrt{d_1^2 + d_2^2}$$

Temperature Correction Formula:

$$SG_{60} = SG_{obs} + [0.00069 - (0.000372 \times SG_{obs})] \times (T_{obs} - 60)$$
$$API_{60} = \frac{141.5}{SG_{60}} - 131.5$$
Show Parameters & Symbols
Symbol Definition Typical Unit
$Z$Gas Compressibility FactorDimensionless
$B_g$Gas Formation Volume Factorft³/scf
$GOR$Gas-Oil Ratioscf/bbl
$64ths$Choke size unit (1/64 of an inch)Size
$BSW$Basic Sediment and Water%
$Shrinkage$Volume reduction due to gas releaseFactor (< 1.0)