Page 183 - Formulas and Calculations for Petroleum Engineering

176 Formulas and calculations for petroleum engineering

: Time of end of linear or pseudo radial flow from plot (dimensionless)
t (L f ) D
C rD : Dimensionless fracture conductivity (dimensionless)
C fD : Dimensionless Wellbore storage coefficient (dimensionless)
L f : Length of fracture (ft)
k: Permeability (mD)
Dt AE : Equivalent Adjusted delta time from derivative curve (h)

Output(s)

C: Well bore storage coefficient (bbl/psi)
: Min Fracture conductivity for infinite conductive fracture (mD ft)
w fk f
L fMP : Length of fracture from match point analysis (ft)
(DP a ) MP : Adjusted Pressure difference at match point from plot (psi)

Formula(s)

m
C ¼ 141:2 q B p ð Þ
g g D MP
k h
1 1
0
!
0:0002637 k Dt AE
2
w ¼ @ * A
Ø m c t
fk f
t L f ðÞ
D MP
!
L 2 f
L ¼ Ø h c C
fMP t fD
0:8936
ð DP Þ ¼ 3:14 k C L
a MP rD f
Reference: Lee, J., Rollins J.B., and Spivey J.P. 2003, Pressure Transient Testing, Vol. 9, SPE Textbook Series, Vol. 9,
Henry L. Doherty Memorial Fund of AIME, Richardson, Texas, SPE, Chapter: 6, Page: 127.
3.4 Analysis of a well from a PI test
Input(s)
P: Average Reservoir Pressure (psi)
q: Flow Rate (STB/day)
P wf : Well Flowing Pressure (psi)
k: Permeability (mD)
B: Volume Factor (RB/STB)
h: Thickness of Reservoir (ft)
m: Oil Viscosity (cP)
r e : Drainage Radius (ft)
r w : Wellbore Radius (ft)

Output(s)
J: Productivity index (STB/day/psi)
k j : Average Permeability (mD)
s: Skin Factor (dimensionless)