The attenuation component of the compressive strength of the oil shale skeleton is [DELTA][sigma], the

pore pressure provided by kerogen pyrolysis is [DELTA]u, the compressive strength of the oil shale skeleton is [sigma]', and the

pore pressure during the oil shale pyrolysis process is [u.sub.t].

The measured hydraulic diffusivity from induced earthquakes is the result of changes in elastic stress and

pore pressure called seismogenic permeability.

[d.sub.1] reflects the rate of volume expansion or reduction of

pore pressure. Recommended range of values is 0.0 to 0.6 (very loose to very dense sands).

The change in pore fluid quality is affected not only by temperature but also by the changes in

pore pressure and rock deformation.

where k is the shaft lining concrete test permeability ([m.sup.2]), [mu] is the viscosity coefficient (1.005 x [10.sup.-3] Pa x s at a room temperature of 20[degrees]C), A is the cross-sectional area of the fluid passing through the material ([m.sup.2]), [DELTA]p is the

pore pressure difference applied between both end planes of the shaft lining concrete sample (Pa), L denotes the shaft lining concrete height (m), and Q denotes the volumetric water flow rate ([m.sup.3]).

where [DELTA]u is change in the specimen

pore pressure that occurs as a result of a change in the chamber pressure when the specimen drainage valves are closed and [DELTA][[sigma].sub.3] is otropic change in the chamber pressure.

where [q.sub.i] (m/s) is the specific discharge vector, p (Pa) is fluid

pore pressure, [k.sub.ij](1/Pa x s) is the tensor of permeability tensor of the medium, [??] ([m.sup.2]) is the relative mobility coefficient, [[rho].sub.f] (kg/[m.sup.3]) is the fluid density, [g.sub.k] (m/[s.sup.2]) is the gravity vector, and [x.sub.k] (m) is the position.

Pore pressure alters the effective stress acting on the rock, which influences rock fracture (Hassanzadegan et al., 2011).

[b.sub.2] > [b.sub.0] is justified because the diffusion of a crack in a finite area may increase the

pore pressure action area paralleling to the crack direction [33].

where [sigma] is the effective stress, p is the

pore pressure, and I is the identity matrix.

Effects of Overlying Water Layer on

Pore Pressure Generation.

Addax Petroleum, an international oil and gas exploration and production company, has acquired Paradigm

Pore Pressure Prediction module to complement its Paradigm range of products.