Drillstring Weight

The drillstring weight, often referred to as the hook load, is the total weight of the drillstring, which includes the drill pipe, drill collars, and any other tools or equipment attached to the string.  The drillstring weight can be measured using various instruments and methods, including hook load indicators and downhole weight sensors.

Weight is Used in Drilling Operations for Several Reasons

Well Control  -  Knowing the weight helps in managing the well's pressure and preventing blowouts.
Load on the Rig  -  It helps in determining the load that the rig's hoisting equipment must handle.
Hydraulic Calculations  -  It is essential for calculating the hydraulic forces and the amount of drilling fluid required.
Drilling Efficiency  -  It influences the rate of penetration and overall efficiency of the drilling operation.

 

Drillstring Weight Formula
\( DS_w \;=\;  DP_w \cdot DS_l  + DC_w \cdot DC_l + BHA_w    \)
Symbol	English	Metric
\( DS_w \) = Drillstring Weight	\(lbm\)	\(kg\)
\( DP_w \) = Drill Pipe Weight per foot	\(lbm \;/\; ft\)	\(kg \;/\; m\)
\( DS_l \) = Drillstring Length	\(ft\)	\(m\)
\( DC_w \) = Drill Collar Weight per Foot	\(lbm \;/\; ft\)	\(kg \;/\; m\)
\( DC_l \) = Drill Collor Length	\(ft\)	\(m\)
\( BHA_w \) = BHA Weight (Bottom Hole Assembly)	\(lbm\)	\(kg\)