Hydromechanical specific energy

Input(s)

WOB: Weight on Bit (lbf)

$\mathrm{A}_{\mathrm{b}}$: Area of Bit $\left(\mathrm{ft}^{2}\right)$

$\mathrm{N}$: Rotational Speedfor a Bit $(\mathrm{ft} / \mathrm{s})$

$\eta$: Factor for Energy Reduction (dimensionless)

$\mathrm{P}_{\mathrm{b}}$: Presure Drop Across Bit (psi)

Q: Flow Rate $\left(\mathrm{ft}^{3} / \mathrm{s}\right)$

ROP: Rate of Penetration $(\mathrm{s} / \mathrm{ft})$

T: Torque (lbf ft)

Output(s)

HMSE: Hydro Mechanical Specific Energy $\left(\mathrm{lbf} / \mathrm{ft}^{2}\right)$

Formula(s)

$$ \mathrm{HMSE}=\left(\frac{\mathrm{WOB}}{\mathrm{A}_{\mathrm{b}}}\right)+\left(\frac{120 * 3.142 * \mathrm{~N} * \mathrm{~T}+1154 * \eta * \mathrm{P}_{\mathrm{b}} * \mathrm{Q}}{\mathrm{A}_{\mathrm{b}} * \mathrm{ROP}}\right) $$

Reference(s)

Samuel. E Robello. 501 Solved Problems and Calculations for Drilling Operations. Sigma Quadrant. 2015. Houston, Texas, Page: 415.