Name

Principal stress in the 2D plane perpendicular to the well

Breakout characteristics


P_{well} = 0 MPa

P_{well} = 34 MPa


σ_{A*} (MPa)

σ_{B*} (MPa)

σ_{90°, R = r} (MPa)

r_{θ = 90°,} σ_{θ = UCS} (cm)

σ_{90°, R = r} (MPa)

r_{θ = 90°,} σ_{θ=UCS} (cm)


Case A

76

134

326

14.8

292

13.6

Case B

60

79

175

< R

141

< R

Case C

76

178

459

23.0

425

21.0

Case D

80

94

200

< R

166

< R

 The computation of the borehole potential damage is linked to no to low wellbore fluid pressure (P_{well}). σ_{90°}, R = r is the circumferential stress at the wellbore boundary in the direction of the minimal 2D stress, r_{θ = }90°, σ_{θ = UCS} is the distance from the wellbore center where the circumferential stress is equal to the UCS of the dolerite (214 MPa), in the direction of the minimal 2D stress, R is the radius of the borehole. Principal stresses in the cross section perpendicular to the well are obtained by diagonalization of the stress state (σ_{ss}, σ_{dd}, τ_{sd}) mentioned in Table 1 and are thus slightly different from horizontal principal stresses