This topic will demonstrate how to determine optimum drilling flow rate for both drilling hydraulic optimization methods (the maximum hydraulic horse power and the maximum impact force). If you don’t know the equations, please read this article first, Determine Optimum Drilling Flow Rate for Basic System – Drilling Hydraulics.
The information is listed below:
Hole size = 8.5 inch
Depth In = 2,000 ft
Depth out = 6,000 ft
Mud properties at starting point
Mud weight = 9.2 ppg
PV = 13
YP = 10
Mud properties at TD
Mud weight = 9.5 ppg
PV = 14
YP = 11
Drill pipe = 5”
Drill pipe ID = 4.2”
Drill pipe tool joint = 6.5”
Drill pipe tool joint ID = 3.5
Drill collar = 6-3/4”
Drill collar ID = 3-1/2”
Drill collar length = 800 ft
Coefficient of surface equipment = 5
Pump Capacity with 6” liner, Triplex pump:
Max flow rate = 900 gpm
Max Pressure = 4500 psi
The best optimization point is at the end so this calculation will be based on Drilling Hydraulics Optimized at the End of the Run.
Coefficient for drill pipe and tool joint
Where;
Cpb = coefficient through inside of pipe and tool joint
Ditj = internal diameter of tool joint, inch
Didp = internal diameter of drill pipe, inch
Cpb = 0.006243486
Coefficient of Annulus around Drill Pipe and Tool Joint
Where:
Cpa = coefficient for the annulus of pipe
Dh = hole diameter, inch
Dp = outside diameter of drill pipe, inch
Dj = outside diameter of tool joint, inch
B = a parameter which takes into account the difference between Q1.86 and Q2. You can just simply select “B” value from the following table.
Cpa = 0.003082686
Total pressure loss coefficient for drill pipe and tool joint
Cp = Cpb + Cpa
Cp = 0.009326172
Coefficient for drill collar
Inside of drill collar
Where;
Ccb = coefficient through inside of drill collar
Didc = internal diameter of drill collar, inch
Ccb = 0.016337
Annulus of drill collar
Where:
Cca = coefficient for the annulus of drill collar
Dh = hole diameter, inch
Dc = outside diameter of drill collar, inch
B = a parameter which takes into account the difference between Q1.86 and Q2
Cca = 0.016559829
Total pressure loss coefficient for drill collar
Cc = Ccb + Cca
Cc = 0.032896
Coefficient for surface equipment
Cse = 5
Viscosity Correction Factor
Vf = (15÷9.5)0.14
Vf= 1.055788
Determine optimum flow rate
Maximum Hydraulic Horsepower
Q = 702 gpm
Maximum Impact Force
Q = 868 gpm
The pump can deliver the maximum flow rate of 900 gpm therefore we can optimize both Maximum Hydraulic Horsepower and Maximum Impact Force.
Reference: Drilling Hydraulic Books
Hi,
Thanks for your perfect explanation.
I would be appreciated if you answer my question. What is the major reason to use HHP optimization or IF?!
Regards
The major reasons are hole cleaning and hydraulic power transfer to the bottom hole.