Strokes – Surface to Bit Strokes

Now let’s calculate Surface to Bit Strokes.

The general formula to calculate Surface to Bit Strokes is as follows:

Surface to bit strokes = drill string volume bbls / pump output in bbl/stk

Step 1 is to calculate Drill String Volume -

- Drill Pipe specs – 6 in OD, 4.356 ID, 9650 feet in lenght

- Drill Collars specs – 8 in OD, 3.5 in ID, 900 feet in lenght

A. Drill Pipe Volume in bbls = (4.356^2 / 1029.4) x 9650 = 177.88 bbls
B. Drill Collar Volume in bbls = (3.5^2 / 1029.4) x 900 = 10.71 bbls

C. To find the total drill string volume we need to add the drill pipe volume in bbls + drill collar in bbls.

Total Drill String Volume = 177.88 bbls + 10.71 = 188.59 bbls

Step 2 is to calculate Surface to Bit Strokes -

If Pump Output = 0.148 @ 95%, then we have all of the information we need to solve.

So,
Surface to Bit Strokes = 188.59 bbls / 0.148

Surface to Bit Strokes = 1274.26 strokes