Page 83 - Open-Hole Log Analysis and Formation Evaluation

The
cases
taken
is

to
CORING
a
not
saturations
coring
saturations.
example,
ensure
covering
given
not
fluid
FLUIDS
of gas,
always
a
that
Once the
oil,
produce
used
no
range
core
objective.
Water
will
important.
is
of
further
and water in
either
coring
4.2
saturation
lists
increase
fluids
Increased
or
and
changes
.
most
~
occur.
decrease
initial
retrieved at surface, precautions
suitable
the
Decreased
initial
must be
the formation. Water-based muds,
reservoir
being
- different documents ten Fable 4.3 saturation changes. "tudes of these It is worthwhile to review the causes and approximate magni- storage. and during transportation at the surface the surface, and reservoir to barrel from the in the core is cut, as it travels time the core at the times: at three different can take place changes in cores Saturation for fluid coring t
TABLE 4.3. Changes in Saturation as a Function of Reservoir Content and Coring Fluid

69
Formation Coring Initial Change Saturations Change Saturation
Content Fluid Saturations Due to in Core Barrel Due to at Surface
Case
1 Oil/water, Water based, O 70 Flushing 30 Shrinkage 12
oil badly G Expansion Expansion 40 ous
productive 6 3 flushed vo ~ cov Ww 30 Expulsion 70 Expulsion — 48 OUR OUB
a
a
°
g
N
we
Ss
506
32,
SS
25
25
53
a
Bo
2
8
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68
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8
5 “wr QO oO gna SHA E28 Bus 2 oO 8 o wT &. oO vo eB 3B 2864 25 3 UST Sd Bu ORs 5 oO 8.32.9 Vu ZEBo5 ts OUB OUB oo t | mw am A 184 || oo i 8 Oo oo O88 So 5 om 5 Gee G BSS s aad o & Re} a c oO aA oO OUBsB OUF
a0
a
6 Oo THA end s8 pow ¥ 6 28é SRS Heo %Z OUB SCRASCRAR Se Qa .$2, on - SCRARSA A aa gi|fil/s3Egtl4téss3 BB 6 a S“SSZQBRBACLR OUR
8
7 eS EBS SzOS yi 8 o g B 4 B a oS 4? OO8B ooocne 418 ooo BE 2B S§ a ooo OUB
38
a
8 Water, B g Vv Oil based, oO s i Invasion OD 8 40 if Shrinkage 35
water badly G Expansion 10 Ou
productive flushed a = W 100 ooo Flushing 60 ooo Explusion 55 NO Nt OusB
oO
Oo
o
ww
an
mt oN
<&3
wn
&
. |)
aaa
Ou8
Sse
bes
gos
wy
UC
AseZ
B25
S63
cS
oe
10 Oil/water, 7B Water based, 2 oO BS 5 eq 2 t F rus. Wn hing on ~ 25 Shrinka ge Qe 22 ® °
depleted badly 15 Flushing 5 Expansion 10 OB
reservoir flushed 30 Invasion 70 Expulsion 68