1. PETE 406
UBD homework

2. Harold Vance Department of Petroleum Engineering
Problem 1
Do Angel first and get circulation rate.
Then calculate the BHP
Harold Vance Department of Petroleum Engineering

3. Angel Minimum velocity
Qmin can be approximated by:
Qmin = Qo + NH
Qo = injection rate (scfm) at zero depth that corresponds to an annular velocity of 3000 ft/min
N = factor dependent on the penetration rate (Appendix C)
H = hole depth, 1000 ft.
Harold Vance Department of Petroleum Engineering

4. Harold Vance Department of Petroleum Engineering

5. Harold Vance Department of Petroleum Engineering
BHP - Angel
Harold Vance Department of Petroleum Engineering

6. Harold Vance Department of Petroleum Engineering
BHP - Angel
Harold Vance Department of Petroleum Engineering

7. Gray’s terminal velocity
This is an iterative procedure.
You have a maximum BHP to remain underbalanced.
You should have a target BHP
You can start with the BHP from Angel (or any other criteria)
Harold Vance Department of Petroleum Engineering

8. Gray’s terminal velocity
Harold Vance Department of Petroleum Engineering

9. Gray’s terminal velocity
Harold Vance Department of Petroleum Engineering

10. Problem 2 - SPP and surface injection rate
Harold Vance Department of Petroleum Engineering

11. Problem 2 - SPP and surface injection rate
Harold Vance Department of Petroleum Engineering

12. Surface injection rate
Q from problem 1
Harold Vance Department of Petroleum Engineering

13. Harold Vance Department of Petroleum Engineering
Problem 3
BHP from Problem 1
multiply by 1.89
using the pa equation for sonic flow, calculate a nozzle area
Harold Vance Department of Petroleum Engineering

14. Harold Vance Department of Petroleum Engineering
Problem 4
Terminal velocity for natural gas
divide the terminal velocity for air by the square root of the gas specific gravity
Calculate new BHP based on the new flow rate and specific gravity
Harold Vance Department of Petroleum Engineering

15. Harold Vance Department of Petroleum Engineering
Problem 5
Calculate an effective ROP
Harold Vance Department of Petroleum Engineering