Lag Time Calculation | Bottom to Surface /Mudlogging Course (2026)

Learn how to calculate Lag Time from Bottom to Surface in this Mudlogging course lecture. This is an essential calculation for Mudlogging Geologists because accurate lag time helps determine when formation cuttings and gas indicators from the bottom of the hole will reach the surface. 📚 In This Lecture: Riser Volume Calculation Casing Volume Calculation Open Hole Volume Calculation Hole Volume Without Pipe Pipe Volume / Outside Volume Annular Volume Calculation Pump Output (L/stk or gal/stk) Pump Efficiency Effective Pump Capacity Lag Time in Strokes Total Pump Rate (SPM) Lag Time in Minutes Practical Lag Time Calculation from Bottom → Surface 📐 Main Equations Covered: Riser Volume = Riser Capacity × Riser Length Casing Volume = Casing Capacity × Casing Length Open Hole Volume = Open Hole Capacity × Open Hole Length Annular Volume = Hole Volume Without Pipe − Pipe Volume Pump Capacity = Pump Output × Pump Efficiency Lag Time (strokes) = Annular Volume ÷ Pump Capacity Total Pump Rate = Pump 1 SPM + Pump 2 SPM Lag Time (min) = Lag Time (strokes) ÷ Total Pump Rate 🎓 Mudlogging Course – Lecture 9 If you are studying Mudlogging, Wellsite Geology, Drilling Engineering, or Oil & Gas, this lecture will help you understand one of the most important calculations used at the rig site. 👍 Like the video, subscribe to Alaa_tech, and share it with other Geology, Petroleum Engineering, and Oil & Gas students. #Mudlogging #LagTime #MudloggingCourse #WellsiteGeology #Drilling #OilAndGas #PetroleumEngineering #Geology #LagTimeCalculation #DrillingEngineering #MudLogger