Beauheim 1987 - Waste Isolation Pilot Plant - U.S. Department of ...

When a match between the data plot and a type curve is achieved, an arbitrary match point is selected, and the
coordinatesof that point on both thedata plot, t and Ap, and the type-curve plot, tD/C,and po, are noted. The
values of CDeZs and Ae-2s of the matched curves are also noted. The permeability-thickness product of the
fracture system (and also of the total system because fracture permeability dominates) and the wellbore
storage coefficient are calculated from Eqs (A-8) and (A-11). The storativity ratio, w, is calculated from:
(A-16)
The dimensionless wellbore storage coefficient for the matrix is calculated as:
0.8936 C
(C 1 - (V@c,), hrw2
(A-17)
This leads to the dimensionless wellbore storage coefficient for the total system:
(A-18)
Then the skin factor is calculated as:
(A-19)
The interporosity flow coefficient is calculated from:
(A-20)
If matrix permeability and geometryare known independently. Eqs (A-14) and (A-15) can be used to determine
the effective dimensions of the matrix blocks.
Unrestricted interporosity Flow
Matrix geometry is more important for unrestricted interporosity flow than for restricted interporosity flow,
because the former is governed by the diffusivity equation. A different set of type curves is used, therefore, to
match transition-period data when unrestricted interporosity flow conditions exist (Figure A-4). Bourdet and
Gringarten (1980) characterize each curve with a different value of the parameter p, the exact definition of
which is a function of the matrix geometry. For example, for slab-shaped matrix blocks, they give:
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