Malek Elgmati, Hao Zhang, Baojun Bai, Qi Qu · Malek Elgmati, Hao Zhang, Baojun Bai, Ralph Flori...
Transcript of Malek Elgmati, Hao Zhang, Baojun Bai, Qi Qu · Malek Elgmati, Hao Zhang, Baojun Bai, Ralph Flori...
Malek Elgmati Hao Zhang Baojun Bai Malek Elgmati, Hao Zhang, Baojun Bai, Ralph Flori and Qi Qu
SPE Americas Unconventional Gas Conference and Exhibition
12–16 June 2011
T lk O tliTalk OutlinesUS Natural Gas Shale ImportanceUS Natural Gas Shale ImportanceResearch Scope & WorkflowMICP ResultsSubmicron Pore Imaging & Reconstructiong gXRD Clay Mineralogy ResultsShale Gas Wettability ResultsShale Gas Wettability ResultsConclusionsAcknowledgments
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US Natural Gas Importance87% of the supplied NG in US was produced domestically (EIA, 2009).US possesses 2,552 Tcf of potential NG (EIA , 2011)Shale gas est reserve represent 32 4% Shale gas est. reserve represent 32.4%
Utica
Fayetteville
Haynesville3
Essential Shale Gas ParametersEssential Shale Gas ParametersDemystifying Shale Gas
Gas-In-Place
PermeabilityMaturation
Demystifying Shale Gas Complexity by…
PetrophysicsPalynology
Geology
Shale Gas Productivity ThicknessOrganic
RichnessMaterial Science
Pore pressureMineralogy
Sh l G BrittlenessShale Gas Characterization
Interdisciplinary Tools4
R h Obj tiResearch Objectives
Look into the submicron pore structure of shale gas to extract the petrophysical properties.
Determine the potential effects of organic matter, rock mineralogy on pore types and permeability.
Identify shale gas porosity types with their magnitudes.
Measure the impact of fracturing fluids on shale gas wettability.y
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Shale Gas Submicron Pore Analysis Workflow
Shale Gas
6 D G Fl M d liy
6. 3D Gas Flow Modeling
1. Mercury Porosimetry
5. Kerogen Analysis
2. Contact 3 FIB/SEM Angle
Measurements
3. FIB/SEM Submicron Imaging4. XRD/Clay
Mineralogy
Element
3D pore reconstruction
analysis
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MICP Results‐Utica Shale Various pore sizes
0.002 106,663
), µ
m Drainage
Imbibition
Various pore sizes and/or different flow units.
0.02
0.2 1,067
10,666
Dia
me
ter
(dp)
su
re,
psi
Imbibition
Major intrusion between 2,000 and
i
2 107
,
uiv
ale
nt
Po
re
Pre
s
Min. dp = 15 nmMax. dp = 15 µmMedian dp = 30 nmTotal ϕ = 14 56%
20,000 psi Eq. dp= 20−200 nm Median d 30 nm
20 11020406080100
Eq
u
Mercury Saturation, SHg %
Total ϕ = 14.56%Avg.(k) = 4.15x10-3 md Median dp= 30 nm
φ = 14.5% k 4 15 micro darcyy , Hg k =4.15 micro‐darcy Resi. Hg is 23.3%
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MICP Results‐Haynesville Shale
One morphology is present.
0.002 106,663
, µ
m
Drainage
Imbibition
Major intrusion between 10,600 and 60 000 psi
0.02
0.2 1,067
10,666
Dia
me
ter
(dp),
ure
, p
si
Min. dp = 4 nmMax. d = 15 µm 60,000 psi
Eq. dp= 2−20 nm Median d = 6 5 nm
0.2
2 107
1,067
vale
nt
Po
re D
Pre
ssu Max. dp 15 µm
Median dp = 6.5 nmTotal ϕ = 10.34%Avg.(k) = 1.38x10-4 md
Median dp= 6.5 nm φ = 10 % k=138 nano‐darcy
20 11020406080100
Eq
ui
Mercury Saturation, SHg %
SHg = 34.64%
k=138 nano darcy Resi. Hg = 26.66%
Mercury Saturation, SHg %
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SEM‐FIB Tomography: 3D SubmicronSEM‐FIB Tomography: 3D Submicron Pore‐Scale Reconstruction
Sample preparation In‐situ specimen
Dual ‐beam
Slicing
In situ specimen preparation
Acquire 200 slices f hi k of 50nm thick
Imaging processing programs.programs.
2D Kerogen model 3D Structured pore model
2D Kerogen 3D Pore Model9
SEM Images of Utica Shale Sample No. 3
Intergranular pore sizes ranged from t
A
15 to 50 nm.Intraparticular or mineral porosity mineral porosity with opening throat is about 5
B
5nm.
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f i h l lSEM Images of Utica Shale Sample No. 2AA
Clay platelets within the quartz grains which create inextricable pore structure with a variety of pore structure with a variety of pore sizes due to diagenesis.
B ‐ Organic matter with a complex textile of porespores.‐Morphology and genesis of OM control th bilit the permeability pathways of gas flow .
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/SE/BSE Images of Utica Shale Sample No. 2C
AA
C
B
‐ Nano‐porosity is observed within pyrite framboids.
B
‐ Pore sizes of 20 and 100 nm.
B
Clay platelets are closely packed together and form a variety of micron and nanoypores (< 2 µm in diameter)
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SEM Images of Fayetteville Shale Sample(A) V Mi it (B) K N it O i b t (A) Vuggy Micro‐porosity, (B) Kerogen Nano‐porosity Occupies about 40−50% of the Organic Matter, and (C) Nano Fractures
A B C
B
C
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3D V l P Si Hi t3D Volume Pore Size Histogram Major pore size is 30nm Major pore size is 30nm Few micron‐cracks or vugs of 3 μm. φT t l = 28% k = 0 01 mdφTotal = 28%, kav. = 0.01 md
(A) (B)
2500
3000Min. dp = 27 nmMax. dp = 4.33 µmMean = 40 nmT t l ϕ 28 22%
1500
2000
of E
lem
ents
Total ϕ = 28.22%Kerogen ϕ = 11.29 %Tortuosity (τ) = 1.44Anisotropy (β) = 0.28Avg. perm. (k) = 0.01 mdkh = kx= ky = 0.018 mdkv = kz = 0.005 md
500
1000No.
o kv kz 0.005 md
φOM = 11.3% 1.44 tortuosity
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09 0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9 1 2 3 4 5 6 7 8 9 10
Mor
e
Equivalent Pore Diameter (dp), µm
0.28 anisotropy14
XRD Clay Mineralogy Results
Semi‐quantitative clay minerals analysis y
Haynesville & Utica‐Indian Castle Fm. have illite%
Utica‐Dolgeville Fm. exhibits high calcite%F ill i i ll Fayetteville compositionally comprise of high quartz%
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Shale Gas WettabilityShale Gas Wettability Six fracturing fluidsg
‐ 2 Polymers‐ 4 Surfactants% ie) 70
80
90
Haynesville Shale (12,000ft)
0.1% concentrations Polished surfaces For 7.5 minutesA
ngle
(Deg
re
40
50
60
70
For 7.5 minutes Results compared to DIW
Con
tact
0
10
20
30
Haynesville becomes hydrophobic with polymers and Flow‐back surfactant.70% illite content
0 100 200 300 400 5000
Tim e (Second)
Surfactants makes all shaleshydrophilic (strongly water‐wet)
7Low TOC 0.81 wt.%
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Utica Shale Dolgeville FmUtica Shale‐Dolgeville Fm.)
8 0
9 0
U tic a S h a le /D o lg e v ille (4 8 7 8 f t) High contact angle near
t Ang
le (D
egre
e
4 0
5 0
6 0
7 0 oil‐wet (60‐80) High calcite content %TOC 0.31 wt.%
0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0
Con
tact
0
1 0
2 0
3 0
FRW‐18 polymer slightly impairs surface wettability t d t t 0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0
6 0
7 0
8 0
9 0
U tic a S h a le /D o lg e v il le (5 ,1 9 7 f t)
Deg
ree)
toward water‐wet .
2 0
3 0
4 0
5 0
Con
tact
Ang
le (D
FRW‐18 & 20 resulted in similar impairment to intermediate water wet
TOC 1.12 wt.%
T im e (S e c o n d )0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0
0
1 0
C intermediate water‐wet
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Utica‐Indian Castle Fm./Fayetteville Shale
Both shales’ have 90
U ti S h l /I d i C tl (4649ft)
Utica Indian Castle Fm./Fayetteville Shale
Both shales have similar wettability trends.50
60
70
80U tica S hale /Ind ian C astle (4649ft)
Ang
le (D
egre
e)
TOC 1.31 wt.%
High illite content% Low TOC content%10
20
30
40
Con
tact
High quartz or ibl illi
0 100 200 300 400 5000
gree
)
7 0
8 0
9 0F a y e t te v i l le S h a le (2 3 5 1 f t )
possibly illite High TOC content%
Con
tact
Ang
le (D
eg
2 0
3 0
4 0
5 0
6 0 TOC 4.04 wt.%
T im e (S e c o n d )0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0
C
0
1 0
2 0
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Conclusions
Haynesville shale exhibited extremely low matrix permeability with a pore size of 2−20 nm, φ=10%.
Utica shale offered better matrix permeability, with a pore throat size of 20−200 nm, φ=14.5%.
ill h l l d i h hi h k d Fayetteville shale resulted in the highest k=0.01 md and φ=28%.Th i tt f F tt ill h l h The organic matter of Fayetteville shale has abundance of nanopores with size of 5−100 nm and occupy 40‐50% of the kerogen bodyand occupy 40‐50% of the kerogen body.
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A robust detailed sequential milling and imaging
Conclusions (cont.) A robust, detailed sequential milling and imaging procedure using SEM‐FIB proved successful.
Various types of porosities (e g interparticular Various types of porosities (e.g., interparticular, intergranular, kerogen, vuggy, pyrite framboids, and fractures) were observed.
Numerous petrophysical properties were extracted from reconstructed 3D submicron pore model.
Calcite content proved the dominant factor changing the wettability of shale gas rock to oil‐wet.
Organic matter content governed the wettability alterations of calcareous samples. 20
Acknowledgments
Dr. Timothy Kneafsey (BNL) Materials Research Center (Missouri S&T) Southwestern Energy Baker‐Hughes Co. RPSEA & DOE
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Thank YouQuestions?Q
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Malek Elgmati Hao Zhang Baojun Bai Malek Elgmati, Hao Zhang, Baojun Bai, Ralph Flori and Qi Qu
SPE Americas Unconventional Gas Conference and Exhibition
12–16 June 2011