Well volumes & circulation time
Annular and string volumes section by section, then the strokes and the minutes to bottoms-up and to a full circulation.
Drilling
Directional survey — minimum curvature
Paste MD, inclination and azimuth and get TVD, northings, eastings, dogleg severity, vertical section and closure — with the well path drawn.
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How it is calculated
- Dogleg angle β = arccos[cos(I₂−I₁) − sinI₁·sinI₂·(1−cos(A₂−A₁))], with ratio factor RF = (2/β)·tan(β/2).
- ΔTVD, ΔN and ΔE are the trapezoidal averages of the direction cosines scaled by RF — the exact integral of a circular arc between two stations.
- Vertical section is closure distance projected onto the section azimuth you choose.
- DLS is the dogleg angle scaled to the interval you quote it over, usually 100 ft or 30 m.
Standards it speaks
Where this stops being true
Minimum curvature is exact arithmetic on the stations you give it, and says nothing about whether those stations are right. Real uncertainty comes from the tool: magnetic surveys carry declination, grid convergence, drill-string and geomagnetic errors that an ISCWSA error model quantifies and this tool does not. For anti-collision work you need that error model and the ellipsoids it produces, not a centre line.
Related tools
ECD & bottom-hole circulating pressure
Annular pressure loss, flow regime and the equivalent circulating density the formation actually sees while the pumps are running.
Bit hydraulics & nozzle selection
Total flow area, nozzle pressure drop, HSI and jet impact force — plus the nozzle size that would put the optimum share of pump pressure at the bit.
Kill sheet — driller's method
Kill mud weight, initial and final circulating pressure and the step-down schedule, for rehearsal and for checking a sheet that has already been worked.
Training aid