The Delft Sand, Clay & Rock Cutting Model, 2019a

The Delft Sand, Clay & Rock Cutting Model.
1000
900
800
700
Esp (MPa)
600
500
400
300
200
100
0
0 10 20 30 40 50 60 70 80 90 100
Bottomhole Pressure (MPa)
hi=0.15 mm unconditioned hi=0.15 mm pc=21 MPa hi=0.15 mm pc=30 MPa hi=0.15 mm pc=35 MPa
hi=0.3 mm unconditioned hi=0.3 mm pc=21 MPa hi=0.3 mm pc=30 MPa hi=0.3 mm pc=35 MPa
1000
900
800
700
S (MPa)
600
500
400
300
200
100
0
0 10 20 30 40 50 60 70 80 90 100
Bottomhole Pressure (MPa)
hi=0.15 mm unconditioned hi=0.15 mm pc=21 MPa hi=0.15 mm pc=30 MPa hi=0.15 mm pc=35 MPa
hi=0.3 mm unconditioned hi=0.3 mm pc=21 MPa hi=0.3 mm pc=30 MPa hi=0.3 mm pc=35 MPa
Figure 9-23: The specific energy Esp and the drilling strength S, theory versus
the Zijsling (1987) experiments.
Blade angle α = 110º, blade width w = 10 mm, internal friction angle φ = 23.8º, external friction angle δ = 15.87º,
shear strength c = 24.82 MPa, shear angle β = 12.00º, layer thickness hi = 0.15 mm and 0.30 mm, effective blade
height hb = 4.04·hi.
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