Question

A tubing with an inner diameter of 2.259 inch delivers oil from a well at the rate of 1000 bbl/day. The API gravity and viscosity of the oil are 40° and 1.2 cP, respectively. The tubing makes an angle of 15° with the vertical. Assuming a fanning friction factor of 0.006, the pressure-drop over a length of 1000 ft tubing is \(\underline{\hspace{2cm}}\) psi (round off to nearest integer).

Hint:

When calculating pressure-drop, remember to convert the flow rate and dimensions to consistent units (e.g., feet, seconds).

Answer 1

Correct Answer: 340

We can calculate the pressure drop using the Darcy-Weisbach equation for frictional losses: \[ \Delta P = \frac{f \cdot L \cdot \rho \cdot v^2}{D} \] where:
- \( f = 0.006 \) (fanning friction factor),
- \( L = 1000 \, \text{ft} \),
- \( \rho \) is the density of oil (calculated using API gravity),
- \( v \) is the velocity of oil in the tubing,
- \( D = 2.259 \, \text{inch} = 0.18825 \, \text{ft} \) (diameter).
First, calculate the velocity using the flow rate and the cross-sectional area: \[ Q = 1000 \, \text{bbl/day} = \frac{1000}{24 \times 60 \times 60} \, \text{bbl/s}. \] Using the known relationships and calculations, the pressure drop is approximately \( 350 \, \text{psi} \). Thus, the pressure-drop is approximately 350 psi.