Drill String Weight

The drill string weight, often referred to as the hook load, is the total weight of the drill string, which includes the drill pipe, drill collars, and any other tools or equipment attached to the string.  This weight is crucial 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.

The drill string weight can be measured using various instruments and methods, including hook load indicators and downhole weight sensors.

 

Drill String Weight formula
\( DS_w \;=\;  DP_w \; DS_l  + DC_w * DC_l + BHA_w    \)
Symbol	English	Metric
\( DS_w \) = drill string weight	\(lbm\)	\(kg\)
\( DP_w \) = drill pipe weight per foot	\(lbm \;/\; ft\)	\(kg \;/\; m\)
\( DS_l \) = drill string 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)	\(lbm\)	\(kg\)