Transcript Ms. Jintan Li - University of Houston

A Time-Lapse Seismic Modeling Study for
CO2 Sequestration at the Dickman Oilfield
Ness County, Kansas
Jintan Li
April 28th, 2010
1
Outline
•
•
•
•
Background/Introduction
Methods
Preliminary Results
Future Work
2
Background
• Area: Dickman Field, Kansas
• Interest: CO2 Sequestration Target
• Deep Saline Aquifer - primary
• Shallower depleted oil reservoir - secondary
• Reservoir Characterization:
• seismic processing, inversion, volumetric attributes,
log analysis, petrophysics, reservoir simulation, and
4D (my part of work)
• Funded by DOE (2009-2012)
3
Dickman Field
Location: Ness County
Kansas State
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First target
Local stratigraphic column based on the well log and mud log
information from Dickman Field
5
Goal of 4D Seismic
To monitor the reservoir at various time:
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•
•
•
Fluid-flow paths
CO2 movement and containment
Post-injection stability
Reservoir properties, etc.
6
Framework
• Reservoir Flow Simulation
• Computer Modeling Group (CMG)
• Gassmann Fluid Substitution
• Seismic Simulation Candidates
• Convolution model
• Full Wave Forward Modeling
7
Flow Simulation Model
Ford Scott Limestone
Cherokee Group
Mississippian Carbonate
Low Mississippian carbonate
Low Cherokee Sandstone
8
3D Flow Simulation Volume
Generated from CMG as
input for fluid substitution.
Each simulation grid
contains:
• P,T, porosity
• Sw,So,Sco2
• API, G, Salinity
• fluid density and mineral
density/ fluid saturated
density
9
Work Flow: Fluid Substitution and Seismic Modeling
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Fluid Substitution
• Kmin: Voigt-Reuss-Hill (VRH) averaging (Hill,
1952)
• Kfluid: brine/water + CO2 or Oil
• Kdry
• Initial Ksat estimation from well logs (Vp,Vs and rho)
• Derive Gassmann’s equation into Kdry, which is a
function of Ksat,Kmin,Kfluid
• Ksat: Gassmann’s equation
• sat: shear sonic log and density log
Vsat: from Ksat and sat
Ro: from impedance contrast
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Preliminary Results
• Reflection coefficients variations versus
changes of fluid properties
– Reflection Coefficient between Mississippian
and Base of Pennsylvanian
– Reflection Coefficients of flow simulated
model after 250 years of CO2 injection
12
3D Seismic area, time slice at the
Mississippian and profile A-A’.
Target
Base of
Penn: Lower
Cherokee
(LCK)
Sandstone~
20% porosity
Mississippia
n: porous
structure
unconformity
limestone/do
lomite/calcite
~20%
porosity
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MSSP and Base_P
Formation
Base of
Pennsylvanian
Upper
Mississippian
Vp
Averaged
from well log
Density
Averaged
from well log
Vs
N/A
Mineral content:
Fluid
subsitution
30% dolomite
70% calcite
Vp/Vs=1.7 for
Limestone
Fluid substitution
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Example2: Ro (Miss and Base_Penn)
Phi
Sco2=0.5
Sbrine=0.5
Crossline
( y cord:m)
Inline ( x coordinate:m)
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Reflection coefficient range: min=-0.0267 max=0.3872
Example2: Ro (Miss and Base_Penn)
Phi
Sco2=0.9
Sbrine=0.1
Crossline
( y cord:m)
Inline ( x coordinate:m)
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Reflection coefficient range: min=-0.3001 max=0.0983
Case II: Reflection coefficients (Ro) after 250 years of
CO2 injection (layer 1 to layer 16: from 150-2350ft ss)
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Future Work
•
Seismic simulation with the convolution
model as a start
•
Incorporate full wave modeling into the
seismic simulation
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Acknowledgement
•
•
•
•
•
Dr. Christopher Liner (PI)
June Zeng (Geology)
Po Geng (Flow simulation)
Heather King (Geophysics)
CO2 Sequestration Team
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END
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Major Formations ( depleted oil Reservoir)
• Mississippian: porous structure unconformity
• limestone/dolomite/calcite
• ~20% porosity
• Base of Penn:
• Lower Cherokee (LCK) Sandstone
• ~20% porosity
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Case I: Ro (Miss and Base_Penn)
Sco2=0.5
Sbrine=0.5
Crossline
( y cord:m)
Inline ( x coordinate:m)
Reflection coefficient range: min=-0.0267 max=0.3872
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Case I: Ro (Miss and Base_Penn)
Sco2=0.9
Sbrine=0.1
Crossline
( y cord:m)
Inline ( x coordinate:m)
Reflection coefficient range: min=-0.3001 max=0.0983
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Case II: Reflection coefficients (Ro) after 250 years
CO2 injection (layer 17 to 32)
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Kmin (MSSP)
• Dolomite (Vdolo=70%) of the volume
• Calcite (Vcal=30%)
Voigt-Reuss-Hill (VRH) averaging (Hill, 1952)
Kdolo=83(Gpa) Kcal=76.8(Gpa)
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Kfluid
• Kbrine (Batzel and Wang, 1992)
• Koil (Batzel and Wang, 1992)
• Kco2 (calculated by KGS online source)
Wood’s Equation:
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Temperature and Pressure
T,P varies with depth (Carr, Merriam and Bartley,
2005)
• Mississippian
T = 0.0131(depth) + 55
• For the deep saline aquifer (Arbuckle
group)
T = 0.0142(depth) + 55
• Mississippian
T: Fahrenheit
P: psi
P = 0.476(depth)
Depth: ft
27
Kdry
Intial Ksat estimation
Shear modulus is calculated by averaging the shear wave
sonic and density log
Kdry can be obtained by rewriting the Gassmann’s equation:
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Ksat
• Gassmann’s Equation
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Reflection Coefficients Calculation
P wave
• Impedance: Z=Vp*Rho_sat
• Reflection coefficient:
i=1,N-1
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Some Fixed Input Parameters
• Salinity: 45000ppm
• API for CO2: 37
• Rho_CO2=46.54*0.01601846 g/cm3
• Averaged shear log velocities: Vp=5420m/s
Vs=1806m/s (Vp/Vs=1.7)
•
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Kfluid: Kco2
Given T, P:
CO2 properties
can be calculated
Missipian
average
depth:4424ft
T=4424*0.0131+
55=110F
P=0.476*4424=
2100 psi
http://www.kgs.ku.edu/Magellan/Midcarb/co2_prop.html
By Kansas geological survey
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4D Seismic Phases
• Phase I: understand the effect of reservoir
fluid properties on the seismic response
• Phase II: apply the fluid changes to the
depleted oil reservoir
• Phase III: apply the fluid substitution
throughout the whole zone of interest
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CO2 Safe Storage
• Four trapping
Mechanisms
– Structural trapping
– Solubility trapping
– Residual gas trapping
– Mineral trapping
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