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PETE 406. UBD homework. Problem 1. Do Angel first and get circulation rate. Then calculate the BHP. Angel Minimum velocity. Q min can be approximated by: Q min = Q o + NH Q o = injection rate (scfm) at zero depth that corresponds to an annular velocity of 3000 ft/min
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PETE 406 UBD homework
Problem 1 • Do Angel first and get circulation rate. • Then calculate the BHP Harold Vance Department of Petroleum Engineering
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
BHP - Angel Harold Vance Department of Petroleum Engineering
BHP - Angel Harold Vance Department of Petroleum Engineering
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
Gray’s terminal velocity Harold Vance Department of Petroleum Engineering
Gray’s terminal velocity Harold Vance Department of Petroleum Engineering
Problem 2 - SPP and surface injection rate Harold Vance Department of Petroleum Engineering
Problem 2 - SPP and surface injection rate Harold Vance Department of Petroleum Engineering
Surface injection rate • Q from problem 1 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
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
Problem 5 • Calculate an effective ROP Harold Vance Department of Petroleum Engineering