Research Article
Effect of Seepage Force on the Wellbore Breakdown of a Vertical Wellbore
Table 1
Common symbols and units.
| | Symbol | The meaning of symbol | Unit |
| | Radial stress | Pa | | Circumferential stress | Pa | | Shear stress | Pa | | Poisson’s ratio | / | | Frame bulk moduli of rock | Pa | | Mineral matrix bulk moduli of rock | Pa | | Radian | rad | | Radial distance | m | | Maximum horizontal principal stress | Pa | | Minimum horizontal principal stress | Pa | | Initial pore pressure | Pa | | Wellbore pressure | Pa | | Pore pressure at the outer boundary | Pa | | Pore pressure distribution around wellbore | Pa | | Wellbore inner diameter | m | | Seepage force | Pa | | Outer diameter of wellbore | m | | Differential pressure | Pa | | Tensile strength of a rock | Pa | | The effective circumferential stress | Pa | | Circumferential total stress formed by formation principal stress | Pa | | Circumferential stress formed by wellbore pressure | Pa | | Circumferential stress formed by changes in pore pressure | Pa | | Circumferential stress formed by seepage force | Pa | | Permeability | m2 | | Flow rate of fluid | m3/s | | Fluid viscosity | Pa/s |
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