Bit-to-Surface Lag Time from Annular Volume Calculator
Enter the declared drilling engineering inputs below to solve t_lag. Variable definitions, units, the default calculation, and the available source trail are included on this page.
What is available in this record
This record provides the functioning calculator, formula, declared variables and units, a reproducible default result, and the available citation metadata. A separately written engineering interpretation has not yet been published for this calculation.
Formula, variables, and default calculation
Reproducible default result
With the default values shown below, the calculation returns t_lag = 42.301166 min. Defaults demonstrate the implementation; they are not recommended field values.
378.9
0.0914
98
Input definitions
V_AV
bblAnnular Volume
PO
bbl/stkPump Output per Stroke
SPM
strokes/minPump Speed
Output definitions
t_lag
Lag Time
V_AV
Annular Volume
PO
Pump Output per Stroke
SPM
Pump Speed
Source and record status
Source metadata identifies the relationship implemented by the calculator. Check the cited edition, unit basis, and scope against the engineering case before operational use.
DrillingFormulas. Lag Time for Drilling Business and How to Calculate Theoretical Lag Time; AAPG Wiki Wellsite Math.
Open source reference