Hydrostatic Pressure for Drilling

Hydrostatic pressure, abbreviated as HP, is the pressure a fluid exerts on an immersed object floating at a certain depth in a liquid.  It is a concept in fluid mechanics and is related to the density of the fluid and the height of the fluid column.

Key Points about Hydrostatic Pressure

• It increases with the depth of the fluid.  The deeper you go in a fluid, the higher the hydrostatic pressure becomes.
• It depends on the density of the fluid.  Denser fluids exert greater hydrostatic pressure for a given depth.
• It is directly proportional to the depth of the fluid.  If you double the depth, you will double the hydrostatic pressure.
• Hydrostatic pressure is a scalar quantity, which means it has magnitude but no direction.  It acts equally in all directions at a specific depth in a fluid.

 

Hydrostatic Pressure (Mud Weight \(\;lbm/gal\)) Formula
\( HP \;=\; 0.052 \cdot MW \cdot TVD \)     (Hydrostatic Pressure) \( MW \;=\; \dfrac{ HP }{  0.052 \cdot TVD }\) \( TVD \;=\; \dfrac{ HP }{  0.052 \cdot MW }\)
Symbol	English	Metric
\( HP \) = Hydrostatic Pressure (psi)	\(lbf\;/\;in^2\)	-
\( MW \) = Mud Weight (ppg)	\(lbm\;/\;gal\)	-
\( TVD \) = True Vertical Dept	\(ft\)	-

  

Hydrostatic Pressure (Pressure Gradient \(\;psi/ft\)) Formula
\( HP \;=\; PG \cdot TVD \)     (Hydrostatic Pressure) \( PG \;=\; \dfrac{ HP }{ TVD }\) \( TVD \;=\; \dfrac{ HP }{ PG }\)
Symbol	English	Metric
\( HP \) = Hydrostatic Pressure (psi)	\(lbf\;/\;in^2\)	-
\( PG \) = Pressure Gradient	\(psi\;/\;ft\)	-
\( TVD \) = True Vertical Depth	\(ft\)	-

   

Hydrostatic Pressure (Mud Weight \(\;lbf/ft^3\)) Formula
\( HP \;=\; 0.006944 \cdot MW \cdot TVD \)     (Hydrostatic Pressure) \( MW \;=\; \dfrac{ HP }{  0.006944 \cdot TVD }\) \( TVD \;=\; \dfrac{ HP }{  0.006944 \cdot MW} \)
Symbol	English	Metric
\( HP \) = Hydrostatic Pressure (psi)	\(lbf\;/\;in^2\)	-
\( MW \) = Mud Weight	\(lbf\;/\;ft^3\)	-
\( TVD \) = True Vertical Depth	\(ft\)	-