350 likes | 744 Views
A Time-Lapse Seismic Modeling Study for CO2 Sequestration at the Dickman Oilfield Ness County, Kansas. Jintan Li April 28 th , 2010. Outline. Background/Introduction Methods Preliminary Results Future Work. Background. Area: Dickman Field, Kansas Interest: CO2 Sequestration Target
E N D
A Time-Lapse Seismic Modeling Study forCO2 Sequestration at the Dickman OilfieldNess County, Kansas Jintan Li April 28th, 2010
Outline • Background/Introduction • Methods • Preliminary Results • Future Work
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)
Dickman Field Location: Ness County Kansas State
First target Local stratigraphic column based on the well log and mud log information from Dickman Field
Goal of 4D Seismic To monitor the reservoir at various time: • Fluid-flow paths • CO2 movement and containment • Post-injection stability • Reservoir properties, etc.
Framework • Reservoir Flow Simulation • Computer Modeling Group (CMG) • Gassmann Fluid Substitution • Seismic Simulation Candidates • Convolution model • Full Wave Forward Modeling
Flow Simulation Model Ford Scott Limestone Cherokee Group Mississippian Carbonate Low Cherokee Sandstone Low Mississippian carbonate
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
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
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
3D Seismic area, time slice at the Mississippian and profile A-A’. Target Base of Penn: Lower Cherokee (LCK) Sandstone~20% porosity Mississippian: porous structure unconformitylimestone/dolomite/calcite~20% porosity
MSSP and Base_P Formation Vp Density Vs Base of Pennsylvanian Averaged from well log Averaged from well log N/A Mineral content: 30% dolomite 70% calcite Fluid substitution Upper Mississippian Fluid subsitution Vp/Vs=1.7 for Limestone
Example2: Ro (Miss and Base_Penn) Sco2=0.5 Sbrine=0.5 Inline ( x coordinate:m) Reflection coefficient range: min=-0.0267 max=0.3872 Phi Crossline ( y cord:m)
Example2: Ro (Miss and Base_Penn) Sco2=0.9 Sbrine=0.1 Inline ( x coordinate:m) Reflection coefficient range: min=-0.3001 max=0.0983 Phi Crossline ( y cord:m)
Case II: Reflection coefficients (Ro) after 250 years of CO2 injection (layer 1 to layer 16: from 150-2350ft ss)
Future Work • Seismic simulation with the convolution model as a start • Incorporate full wave modeling into the seismic simulation
Acknowledgement • Dr. Christopher Liner (PI) • June Zeng (Geology) • Po Geng (Flow simulation) • Heather King (Geophysics) • CO2 Sequestration Team
Major Formations ( depleted oil Reservoir) • Mississippian: porous structure unconformity • limestone/dolomite/calcite • ~20% porosity • Base of Penn: • Lower Cherokee (LCK) Sandstone • ~20% porosity
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
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
Case II: Reflection coefficients (Ro) after 250 years CO2 injection (layer 17 to 32)
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)
Kfluid • Kbrine (Batzel and Wang, 1992) • Koil (Batzel and Wang, 1992) • Kco2 (calculated by KGS online source) Wood’s Equation:
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 • P = 0.476(depth) T: Fahrenheit P: psi Depth: ft
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:
Ksat • Gassmann’s Equation
Reflection Coefficients Calculation • Impedance: Z=Vp*Rho_sat • Reflection coefficient: P wave i=1,N-1
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)
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
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
CO2 Safe Storage • Four trapping Mechanisms • Structural trapping • Solubility trapping • Residual gas trapping • Mineral trapping