Page 318 - Fundamentals of Gas Shale Reservoirs

298 PERFORMANCE ANALYSIS OF UNCONVENTIONAL SHALE RESERVOIRS

macrofractures to increase oil extraction from the matrix. To 1
optimize the zipper frac well spacing parameters requires c p (13.B.2)
reservoir modeling. o
1 B
c w (13.B.3)
13.8 CONCLUSION w B w p o

Well performance and transient test analyses are the critical c 1 B g (13.B.4)
components of reservoir characterization for assessing the g B g p o
ultimate oil recovery from primary production and EOR
techniques in unconventional reservoirs. Besides pressure
and flow rate analysis, we rely on special core analysis NOMENCLATURE
measurements, reservoir fluid PVT characterization, and
inflow tracer analysis to determine reservoir stimulation Basic Symbols
effectiveness.
In this chapter, first we presented practical approaches F Force
for analyzing well performance in shale oil and gas reser- L Length
voirs. Next, we showed how to use the well performance M Mass
results to estimate the ultimate oil and gas recovery from P Pressure
primary production, and, finally, we shed light on the con- T Time
nection between well test analysis and assessment of EOR
for unconventional reservoirs.
Field Units

ACkNOWLEDgMENTS BBL Barrel
cp Centipoise
The authors gratefully acknowledge the support from D Day
Marathon Center of Excellence for Reservoir Studies ft Feet
(MCERS), the Unconventional Oil and Gas Institute (UNGI), md Millidarcy
and Marathon Oil Corporation, which have provided us the
opportunity to conduct research both in conventional and mD Millidarcy
unconventional reservoirs. psi Pound per square inch
RB Reservoir barrel
SCF Standard cubic feet
APPENDIx 13.A AL BLACk OIL PARAMETERS
STB Stock tank barrel

M o M (13.A.1) Symbols
o t
t
a Gas adsorption quantity, scf/ton
c
M g M (13.A.2) A Surface area of the matrix block, L (ft )
2
2
g t m
t b Decline exponent
K
M w M (13.A.3) b Knudsen slip coefficient for component c, atm
c
w t
3
3
t B Formation volume factor, L /L (RB/STB)
3
3
M k ( wo g) (13.A.4) B Gas volume factor, L /L (RCF/SCF)
,,
feff g
,
B Oil volume factor, L /L (RB/STB)
3
3
k k k o
feff m f f (13.A.5) B Water volume factor, L /L (RB/STB)
3
3
,
w
3 ‐ 1
c c c c Fracture compliance, L F (ft/psi)
t fm t f t m (13.A.6) f
2
c Gas compressibility, LF 1 1/psi
g
2
ĉ Oil compressibility, L F 1 1/ psi
o
2
APPENDIx 13.B gAS-CONDENSATE c Apparent oil compressibility, L F 1 1/ psi
oa
2
COMPRESSIBILITY c Rock compressibility, L F 1 1/ psi
ϕ
c Water compressibility, L F 1 1/ psi
2
c c Sc Sc Sc (13.B.1) w 2 1
t w w o o g g c Total matrix compressibility, L F 1/ psi
t,m