A

Drainage area

A ?

Drainage area constant

AOF

Absolute open flow potential of a well or the deliverability zero sandface pressure

b

Intercept on Cartesian plot of transient-test pressure data, psi

b ?

Intercept on semilog plot of transient-test pressure data rate, psi/stb/d

B

Coefficient in the stabilized deliverability equation

c _f

Formation compressibility

c _g

Gas compressibility

c _o

Oil compressibility

c _t

Total compressibility

c _w

Water compressibility

C

Wellbore storage constant

C ?

Shape factor conversion constant

C _D

Dimensionless wellbore storage constant

D

Non Darcy flow coefficient,

e

2.7182

E i

Exponential integral

erf

Error function

exp

e

F

Absolute open flow potential of a well

F ?

Ratio of pulse length to total cycle length

F _CD

Dimensionless flow capacity

F _cor

Correction factor when calculating permeability

G*

Geometric fraction for vertical interference testing

G _P

Primal geometric fraction for vertical pulse testing

G _R

Reciprocal geometric fraction for vertical pulse testing

h

Formation thickness, ft

h _D

Dimensionless thickness for horizontal fracture cases

h _p

Perforated interval, ft

J

Productivity index

J ?

Modified productivity index for a deliverability test

k

Permeability, mD

k _m

Matrix permeability, mD

Average permeability for anisotropic system, mD

k _f

Fracture permeability, mD

k _g

Gas permeability, mD

k _h

Horizontal permeability, mD

k _ma

Matrix permeability, mD

k _max

Maximum directional permeability, mD

k _min

Minimum directional permeability, mD

k _o

Oil permeability, mD

k _s

Permeability in the skin zone, mD

k _v