Characteristics and Cutoff of Porosity and Permeability of the Effective Volcanic Gas Reservoirs of the
Lower Cretaceous Yingcheng Formation in Songliao Basin, Northeast China*
YuLong Huang1, Yuhui Feng1, and Pujun Wang1
Search and Discovery Article #10635 (2014)**
Posted August 29, 2014
*Adapted from oral presentation given at 2014 AAPG Annual Convention and Exhibition, Houston, Texas, April 6-9, 2014
**AAPG © 2014 Serial rights given by author. For all other rights contact author directly.
1
College of Earth Sciences, Jilin University, Changchun, China ([email protected])
Abstract
Effective volcanic gas reservoirs of the Lower Cretaceous Yingcheng Formation in the Xujiaweizi Depression of northern
Songliao Basin are primarily found in rhyolite, rhyolitic welded tuff, trachyte and basalt. There are six types of reserve spaces
together with their assemblages which indicate effective reservoirs, including unfilled vesicles, dissolved pores, inter-spherulite
pores, columnar jointing fractures and tectonic fissures. Porosity of 1262 pieces of volcanic rock samples mainly ranges between
1.5% and 10%, and those of intermediate and low porosity below 10% amount to a percentage of 88.4%. Permeability of 1197
pieces of samples ranges between 0.01×10-3 μm2 and 1.0×10-3 μm2, and those of low permeability less than 0.1×10-3 μm2
amounts to 66.7%. Consequently, these indicate volcanic reservoirs with characteristics of intermediate to low porosity and low
permeability.
By means of porosity, permeability and productivity testing data from eighty wells, three methods including distribution
function curves, cross-plots and statistical method are used to determine the porosity and permeability cutoff values of the four
types of volcanic rocks respectively. The results of porosity and permeability cutoff of basalts are 6.2%, 0.005×10-3 μm2 and
trachyte 4.2%, 0.011×10-3 μm2, rhyolite 5.4%, 0.046×10-3 μm2, rhyolitic welded tuff 5.7%, 0.036×10-3 μm2. Moreover, the
results are proved by data of other twenty wells from neighboring areas with an order of accuracy of 90%. The lower limits of
reservoir porosity and permeability of different types of volcanic rocks are primarily related to their reservoir heterogeneities,
which were mainly controlled by reservoir space constitution and lengthwise continuity. The lower limits of porosity of trachytic
and rhyolitic reservoirs which show larger thickness of continuous lengthwise layers, compared to that of less continuous basalt
and ignimbrite. Synchronized mineralogical studies indicate a higher content of dark-colored minerals in basalt which is easier
to form secondary fractures that resulted by a higher stress sensitivity. Moreover, dark minerals and mafic feldspars are more
easily altered into clay minerals which expand with water and thus forming micro-fractures. As a result, permeability of basalt is
the best among all the volcanic rocks, and the lower limit of reservoir permeability is significantly lower than the other three
types.
References Cited
Nelson, S.T., 2009, The central Colorado Palteau laccoliths a temporal and spatial link to voluminous mid-Tertiary magmatism
in Colorado and the Great Basin: GSA Abstracts with Programs, v. 41/6, p. 18.
Smith, R.L., and R.A. Bailey, 1966, The Bandelier Tuff; a study of ash-flow eruption cycles from zoned magma chambers:
Bulletin of Volconology, v. 29, p. 83-103.
Jilin University
Characteristics and Cutoff of Porosity and
Permeability of the Effective Volcanic Gas Reservoirs,
Songliao Basin, NE China
Huang Yulong, Feng Yuhui, Wang Pujun
[email protected]
College of Earth Sciences, Jilin University, Changchun, China
Houston 8-Apr-2014
• Volcanic reservoirs in Songliao Basin
• General characteristics
• Effective reservoirs: Definition, methods and results
• Characteristics of effective volcanic reservoirs and their
controlling factors
• Conclusions
Volcanic reservoirs in the world
Clastic reservoirs
（approx. 60%）
Carbonate reservoirs
水
water
（approx. 40%）
Volcanic reservoirs
（less than 1%）
Long history, ‘low yielding’
火
fire
Volcanic reservoirs in China
Junggar Basin
C-P
Paleozoic
Mesozoic
Songliao Basin
K
Bohai Gulf Basin
E
Cenozoic
Proved reserves:
Oil ~0.5×108t, gas ~4000×108m3
（PetroChina, 2007）
Distribution of volcanic reservoirs in sedimentary basins of China
Volcanic reservoirs in Songliao Basin
• 80 boreholes
• 4 with continuous core samples
• Tens to hundreds meters long core
sections for each
Beijing
Xujiaweizi depression
Suite Ⅱ: mafic-intermediate volcanic rocks,
especially basaltic and trachytic lava rocks
Changling depression
Suite Ⅰ: silicic volcanic rocks,
especially lava and ignimbrite
Source rocks: dark mudstone with
intercalated coal
Distribution of the depressions in Songliao Basin
the Cretaceous stratigraphic column
sandwich-like source-reservoir-seal assemblages
DS3-1
DS3-3
1.9
2.0
sedimentary
2.1
basalt
trachyte
volcanic
(s) (s)
Double travel time
2.2
2.3
2.4
sedimentary
2.5
2.6
top of volcanic
T41
bottom of volcanic
boundary of trachyte
0
500
1000m
Typical seismic profile of a volcanic-sedimentary strata in Songliao Basin
T4c
Data come from
• ~80 boreholes (with natural gas yielding test data to prove whether the
reservoir is effective or not)
• 4 with continuous core samples (to do series of tests)
• Tens to hundreds meters long core sections for each well
Series of tests and analyses
•
•
•
•
•
Core analysis
Casting thin sections
Porosity and permeability
Mercury injection
SEM (scanning electron microscope)
Boreholes
Y3D1
DS3-1
XS9-1
XS1-2
lithology
basalt
trachyte
rhyolite
ignimbrite
lithofacies
effusive
extrusive
extrusive
and effusive
explosive
length of core sections
In meters
254
85
228
304
Pores and fractures in volcanic rocks
A- vesicles in rhyolite
B- intergranular porosity in volcanic breccias
C- contraction joints in rhyolitic ignimbrite
D- dissolution porosity in rhyolite
E- dissolution fractures in rhyolitic breccia lava
F- vesicles and tectonic fracture in rhyolite
Reservoir quality
Medium - low porosity
•
low permeability
-
351
N=1262=1262
=0.2%
Min=0.2%
=21.4%
Max=21.4%
=5.8%
Avg.=5.8%
5.2%
Med.=5.2%
278
300
215
200
145
128
77
100
45
10
8
0
2
4
6
8
10
12
14
16
18
3
2
20
22
/%
Porosity (%)
600
/
number of samples
number of /samples
400
•
531
=1197
N=1297
=192×10-3 μm2
Min=0.003md
=0.003×10-3 μm2
Max=192md
0.05×10-3 μm2
mean=0.05md
Med.=0.03md
0.03×10-3 μm2
500
400
300
214
200
100
0
154
0
209
54
10
0.001 0.005 0.01 0.05
0.1
1
5
-3
10
10
2
3
10
50
100
200
2
permeability
/×10 (md)
μm
high Φ（>10%）--------------11.4%
high K（≥5md）-----------------2.1%
medium Φ （5%~10%）----41.3%
mid-high（ 1~5md ）------------4.5%
low Φ （<5%）----------------47.3%
medium（ 0.1~1md）------------17.5%
low（ <0.1md）-------------------75.9%
number of samples
number of samples
Correlation and sequencing of the porosity and permeability of
the four types of volcanic reservoirs
lithology
basalt
trachyte
rhyolite
ignimbrite
porosity
Ⅳ
Ⅱ
Ⅰ
Ⅲ
permeability
Ⅰ
Ⅳ
Ⅲ
Ⅱ
porosity (%)
basalt permeability (md)
porosity (%) trachyte permeability (md)
porosity (%)
rhyolite permeability (md)
porosity (%) ignimbrite permeability (md)
Pore-throats of volcanic rocks compared to clastic rocks
Porosity: 16.3%
Permeability: 1.88×10-3μm2
Modified from Nelson, 2009
Porosity: 5.8%
Permeability: 0.05×10-3μm2
Definitions
Effective reservoir
-Reservoirs with relatively higher porosity and permeability, which
are able to yield enough fluid (oil, gas or water) with an commercial
value of productivity.
- Total gas equivalent higher than 40, 000 m3/d (in the study area)
Cutoff of porosity and permeability
-Reservoirs with porosity and permeability less than cutoff value will
not be able to yield commercial value of fluids.
Two statistical methods
Distribution function curves
Porosity (%)
Porosity (%)
Trachyte
Frequency (%)
effective
Non-effective
Rhyolite
effective
Non-effective
Frequency (%)
Basalt
Porosity (%)
effective
Non-effective
Frequency (%)
Frequency (%)
effective
Non-effective
Porosity (%)
Rhyolitic ignimbrite
Distribution function curves
effective
Non-effective
Frequency (%)
Frequency (%)
effective
Non-effective
Trachyte
Basalt
Frequency (%)
Frequency (%)
effective
Non-effective
Rhyolite
effective
Non-effective
Rhyolitic ignimbrite
effective
non-effective
permeability (md)
permeability (md)
Cross-plots
porosity (%)
porosity (%)
Trachyte
permeability (md)
permeability (md)
Basalt
porosity (%)
Rhyolite
porosity (%)
Rhyolitic ignimbrite
Results
Cutoff of porosity and permeability of the four types of volcanic rocks
lithology
cutoff value
porosity
permeability
(%)
(md)
basalt
6.2
0.005
trachyte
4.2
0.011
rhyolite
5.4
0.046
ignimbrite
5.7
0.036
25
20
10
0
6
0
10 10~30 30~50
(a)
0
50
10
12
9
6
7
4
5
3
0
10 10~30 30~50
50
effective thickness
(m) (m) (b) effective thickness
(m) (m)
rhyolite
3
2
2
1
1
0
1
0
10 10~30 30~50
50
(c) effective thickness
(m) (m)
number of layers
30
trachyte
15
number of layers
basalt
40
number of layers
number of layers
Application to determine the effective thickness
ignimbrite
15
11
10
12
9
6
3
1
1
0
10 10~30 30~50
50
(d) effective thickness
(m) (m)
effective thickness (m)
commercial
The thicker of the effective reservoir,
the higher yielding of natural gas
gas yielding per day (m3)
Basaltic
Graphic log of a single basaltic lava flow unit
Upper vesicular zone
Thickness: 8.05 meters
Vesicle porosity by image
analysis: 10%~25%
Porosity: 4.5%~16.9%
Medium massive zone
Thickness: 21.6 meters
Vesicle porosity by image
analysis: <4%
Porosity: 1.1%~5.2%
Lower vesicular zone
Thickness: 4.3 meters
Vesicle porosity by image
analysis: 6%~15%
Porosity: ~5.0%
Basaltic
Basaltic
lity
porosity
thickness lithology lithofacies
(m)
,L1
( 1O-3,lUll 2)
(%)
0
40
brecciated
I
t
10
vesicle
fracture
total image
porosity (%) porosity (%) porosity (%)
·10
30
· 10
30
-10
30
max imum pore
radius
•
0.001
10
average pore
radiu s
.
0.001
10
t
0- -
8 .1
<I
vesicular
I
\
\
I
lot
lU5
ma ssive
n
1
I
1
I
I
I
I,
,,
. '::L - ..
,
(
\
}
4.2
I
J
~
\
~.-'',i.
)
I
,
....
~
2 Ui
lllEtssi ve
m
j II
8 .1
vesicular
~
f
.•
'\",
....
_ 0.
~ -
- -'"
f\
'.
..,'.,.
'
~
Controlling
rac ures, infilling
I I n9
on ro I 9 factors:
fac ors: primary
pnmary vesicles
veslc es and
an fractures,
Trachytic
Trachytic
RHOB (glcm 3)
GR(API)
LLD(Qm)
0 - - - 240
2 - - - 20000
2
3
densi~
depth ~-----llitlhol ()gY I--------I
CAL (in)
LLS (Qm)
6 - - - - 16
2 ,------- , 20000
(glcm )
NPHI (%)
42
(m)
permeability
porosity
(%)
-18
DT (Ils/ft)
140 -----------. 40
2 - - - - 3 0 - - 10
mroumum pore
throat radius (fUll)
0.001
-~
. -
- 10
~-----.--------~------------~
horizontal
(md)
0.001 -
1
vertical
(lO-3fUll 2)
0.001 - - 1
3150
3200
3250
Controlling
fractures
ontro Ing factors: primary
primary vesicles
ves c es and
a
ractures
average pore
throat radius (fUll)
0.001
-~
. -
- 10
Rhyolitic
Rhyolitic
RHOB (glem 3)
LLD (Qm)
GR(API)
0
300
3700
LLS (Qm)
0 - - - -- 15
2 .--------- 2000
~
,/
3720
>-
I
I
I
rI
? I1
z..
I
~
1
i llI
\
I
I
z:r
~
-'
I
3740
42
CAL (in)
;;
"
.,
"-
""-
",
"v
"-
'" '"
'"
'" '"
"v
13-
I;:r
I"
I'
"v
'"
'"
'" '" '"
' '" '"
'" '" '"
'
"v
'(
(,
'" '" '"
'"
"v
"v
J.
'j
,
c::
"
'"
!I!IJII
~
E
~
IS)
;,
l ~ 'J
<; II <;,'
:.
<p
'"
:
'~t.<;)
o-
-
~
c
10
vertical
(IO· 3Jl111 2)
(I O·3 ~jm2)
20
10
0.01 -
10
average pore
throat radius (flm)
0.001
•
10
t:o
-r--, ~
<
'"
3
0.01 -
F
'" '" '"
3760
DT (flS/ft)
'"
'" '" '"
'"
'" '" '"
horizontal
2 -
•
(%)
140 -------- - - 40
~
~~
0.001
porosity
-1 8
'" '" '"
I" '"
densi7,
(glcm )
NPHI (%)
litbology
maximum pore
tbroat radius (!lill)
permeability
3
2 - - - 2000
Iclenth
-r
(m)
2
~
~
E
~
~
~
r
),1
~
~
i==
I
6
II
t--
~
=
~
=-
f - - I-
~
~
r~~
~
~
r-
1=
1=
~
;;:
;;;
=.
~
r-
~
-
:=-
-
f--
t=
t=:::'
,...
-
==
~
~
~
F
~
~
»
~
F-
~
'
=
=
.)
l"-
~
~
T
:.--
Controlling factors:• primary vesicles and fractures
Rhyolitic ignimbrite
Fa value calculation for welding
degree determination
Graphic log by continuous core sections
Zonation of welding determined
by Fa value
Welding zonation and porosity changes of ignimbrite:
Indication from outcrops
Porosity decreases with welding
（Cas and Wright, 1987）
porosity (%)
Porosity zonation of ignimbrite（Smith and Bailey, 1966）
Three layers of relatively high porosity and permeability
dissolution porosity
Intra-granular residual porosity
Inter-granular residual porosity
Rhyolitic
Rhyolitic ignimbrite
ignimbrite
RHOS IgJem' )
LLD 10m)
GRIAPI)
0 - - - 3"
lithology
1m)
LLS 10m)
~
'r'>
355U
"
II ,
/\
~
1\
,
/\
~
1\ ,
1\
"
1\
,
1\
"
1\ ,
/\
A,
1\ ,
J\
~
1\ ,
J\
~
1\ ,
J\
'\. 1\ ,
J\
A,
II ,
J\
A.
1\ ,
1\
". f\ ,
1\
II ,
(\
", 1\ ,
1\
"
"
1\ ,
1\
1\ ,
1\
A,
1\ ,
1\
"
1\ ,
1\
'"
1\
,
1\
"" 1\ ,
/\
"
3600
I
~;
"
,
;p.
(
i'
"'J 1
m/\/\
"v
m/\ II
,
~
--2-
mIl 1\
~
1= ~
E=
r- t-
r- t-
r- tt;;;; t-
~ t-
=
~
~~
0:::
r==-
E:"'"
F
F
t::::=
E::::
t-
~
t;:::
~
r
I-~.~
--
~
I ~ I>
f-l
~ .oOI
~
~
' t;>
". , m/\ 1\
f
vertical
horizontal
F=
=
f>
'"', , lIl/\ /I
"- ,
==
~ l-
' /'.
0 - - 10
F= ~
~
}
'\, , m/\II
3650
~
,
...: .
/" ) f
)
zonation
0,00 1 - - <0
...
~
'"
1%)
."
~~~
r- "t
/ , ) ' /'\
"
~ .OO]
average pore
"J - - 2.1
NP HII%)
"
~
3500
porosity
80 .------------ 20
2 '•••••••• laooo
0 - - - - IG
2 D.
DT I ~s/ft)
maximum pore
throat radius I~m)
permeabi lity Imd)
densi t y
Ig/em' )
2 - - -· 2(1000
depth
CAL lin)
,
1
r-
~ l-
0.(0) - - - - - - 10
non-welded
1-' ' -
~I
I-
i ght 1Y
w{>lrli>d
r- t::J
t- tDlediu:n
t-
t-
~
~ j-
I=-
r
I-
r
I-
=
r
I-
~
~
l-
t:- t-
t-
t-
r-
r-
~
throat radius I~m)
<0
welded
densely
welded
non-welded
Controlling
factors:• welding,, compaction and dissolution
c
on
Conclusions
reservoir characteristics
basalt
trachyte
rhyolite
ignimbrite
porosity
(%)
range
1.1~16.9
0.2~7.2
0.6~16.3
0.2~21.4
cutoff
6.2
4.2
5.4
5.7
permeability
(md)
range
0.006~51.1
0.004~1.686
0.005~192
0.003~34.7
cutoff
0.005
0.011
0.046
0.036
primary
vesicle
vesicle
vesicle
lithophysae
intergranular pores
dissolution
pores
interspherulitic
dissolution
devitrification
88
40
44
shape
sheet,
wedge
wedge, lens,
dome
wedge, lens,
dome
sheet, wedge
internal structure
laminated
laminated
circle-layered
laminated
circle-layered
laminated
thickness (m)
100~250
250~460
100~700
300~500
extended length (km)
10~22
3~7
2~9
4~10
Sketch section map showing the
distribution and proportion of
effective reservoirs in each of the
four types of volcanic rocks
(not to scale)
heterogeneous
6
homogeneous
reservoir body
average (m)
homogeneous
effective thickness
secondary
heterogeneous
pore spaces
Conclusions
Seismic profiles and interpretations
of the four types of volcanic rocks
-basaltic: effusive, sheet, wedge, subparallel, continuous
-trachytic: extrusive, lenticular,
discontinuous
-rhyolitic: extrusive and effusive, dome,
circle-layered
-ignimbrite: explosive, sheet, subparallel, continuous
trachytic
basaltic
rhyolitic
ignimbrite
Conclusions
 Cutoff and reservoir heterogeneity
• Cutoff is strongly determined by reservoir heterogeneities, which were
essentially determined by primary porosities (vesicles and contractions joints),
and then by secondary changes (infilling, compaction, dissolution and tectonic
fracturing)
• The more heterogeneous, the higher of the cutoff value (especially porosity)
• Heterogeneous -- basalt, ignimbrite
• Homogeneous -- trachyte, rhyolite
 More applications
•
•
Drilling trajectory
-vertical
-inclined
-horizontal
Fracturing--need or not?
 Future works
• For homogenous volcanic reservoirs, quantifying the micro-porosities
• For heterogeneous volcanic reservoirs, quantifying macro-porosities and
fractures
• Pore throats and pore networks of different magnitudes in different scales