Tonmiles – Audit

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Tonmiles, release 1, issued 18 May 2008. AUDIT version.

The current release of this worksheet exists in different versions. They are identical apart from the way they are formatted. The Work version hides intermediate calculations and allows the user to see the results just below the inputs. This is useful for quick “what-if” games, changing various inputs to see what works best. The Audit version displays all intermediate calculations. The PDA version removes all text and formats the input and output fields for optimum viewing on a mobile, small-screen device.

User input


Round or short trip, factor 1One way trip, factor 0.5Drill, no ream, factor 3Drill, ream once, factor 4Drill, ream twice, factor 5Run casing or tubing, factor 0.5

Select the operation to be calculated.





Shallowest measured depth (round trip, enter zero). MDupper =





Greatest measured depth. MDlower =





Length of a stand, OR for running casing, length of a joint. Lstand =




psi/ftSG or kg/lppglb/ft3ppbkPa/m

Drilling fluid density. ρm =





Drillpipe weight per unit length (recommend API approx wt, see RP7G Table 8 or 9) OR casing. wtcdp =





Heavy weight drill pipe average weight per unit length. wtchwdp =





HWDP length. Zero for running casing. Lhwdp =





Drillcollar OD. Ddc =





Drillcollar ID. ddc =





BHA length. Zero for running casing. Lbha =





Travelling block weight. mtb =


Click here when any values are modified to update the result.


Weight of the BHA

Buoyancy factor from the mud gradient.

Buoyant weight of the BHA including HWDP in excess of the weight of the same length of drillpipe.

Calculate the work at the upper and lower depths in Joules. Note; g is the acceleration due to gravity, 9.81 m/s2.

Subtract the upper from the lower, then multiply by the operation factor to arrive at the total work done.


For the selected operation, the work done by the drilling line is

Worksheet references

SG of steel from taken as 7.85.

Drilling Data Handbook, 6th Edition, Institut Francais du Petrole.

Release 1 of this worksheet 18 May 2008.

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