CO2-PENS: A CO2 Sequestration Systems Model Supporting Risk-Based Decisions
Philip H. Stauffer, Hari S. Viswanathan, George D. Guthrie, Rajesh J. Pawar , John P. Kaszuba, James W. Carey, Peter C. Lichtner, Chuan Lu,
Unclassified
Ionnis N. Tsimpanogiannis, Hans J. Ziock, Manvendra K. Dubey, Seth C. Olsen , Steve J. Chipera, Julianna E. Fessenden
LAUR 05-6262
Abstract
1)A Science-Based Decision Framework for
Predicting Engineered Natural Systems
The Zero Emissions Research and Technology (ZERT)
project at the Los Alamos National Laboratory is
studying the injection of CO2 into geologic repositories.
We are formulating the problem as science based
decision framework that can address issues of risk, cost,
and technical requirements at all stages of the
sequestration process. The framework is implemented
in a system model that is capable of performing
stochastic simulations to address uncertainty in different
geologic sequestration scenarios, including injection into
poorly characterized brine aquifers.
CO2-PENS
Conceptual
Framework
CO2-PENS
Processes level laboratory experiments, field
experiments, modeling, economic data, and risk theory
are used to support the system level model that will be
the basis for decision making. The current system
model, CO2-PENS, is already proving to be useful in
showing complex interactions between the different
components of the framework. The system model also
provides a consistent platform to document decisions
made during the site selection, implementation, and
closure periods.
Model Root
The model root is based on the conceptual framework.
The system model is designed to adapt to changes in
understanding and can be modified quickly to add new
processes and interactions. Identification of additional
processes and interactions can come through use of the
system model, literature searches, and through
independent investigations undertaken to support the
decision making process.
The model root, created in GoldSim, is used to manage
global variables such as time, CO2 mass balance, total
risk, well statistics, and costs. GoldSim is also used to
sample stochastic distributions and allows robust
uncertainty analysis. Subprograms, written in the
language of choice (i.e., FORTRAN, C) are called from
the model root. These subprograms can be changed to
include more detailed calculations as data and theory
are revised. Multiple options for subprograms allow
flexibility. For example, limited availability of data
may obviate the need for a complex subprogram.
2) CO2-PENS System Level Model used to explore
complex interactions between Risk, Cost, and
Technical Requirements
Main Simulation Control
Risk Analysis
Hobbs Injection Site
Field injection
Lab experiments
Numerical simulations
Example Output
3) Process Level Investigations used to
Support System Level Calculations
Reservoir Processes >> CO2 Fate and Transport
Significant Clay Growth Occurs
Core Flood Experiment Calcite dissolution
pH
Numerical Modeling using LANL
Porous Flow Codes FEHM and PFLOTRAN
Image by
UC Davis
Mole fraction dissolved CO2
(m)
Data Analysis by
New Mexico Tech
Visualization of
Wormhole formation
Borehole failure and repair information
CO2 Mineralization:
0.2 m x 0.2 m
Numerical simulation
using FLOTRAN
Dawsonite Synthesis Experiments
Cement Degradation >> Wellbore failure
8000 yrs
SACROC Core Analysis
(m)
(m)
Multiphase flow; Water -CO2 - Air: Fractured porous media:
Reactive chemistry: Thermal effects: Density driven flow:
Supercritical CO2 : PFLOTRAN is now massively parallel
Analytical Solutions for Wellbore Failure
Obtain leakage rates using semi-analytical solutions,
collaboration with M. Celia and others at Princeton
Multiple layers
Reduced complexity relative to
FEHM simulations
Couple analytical solutions to
the CO2-PENS system model
Reservoir Variables Input
Output concentration 10 m above an injection site
3cm
Cement
CO2 mass in the reservoir and various leakage pathways
FLOTRAN reactive chemistry simulations
Nordbotten, J, M. Celia, S. Bachu, Water
Resources Research, 2004.
CO2 Cement Brine
Experiment
pH sensitive dye
Ca(OH)2 (high pH) ->
CaCO3 (low pH)
PCO2 = 13.8 MPa
Reaction zone
30 yr in-situ CO2 exposure history retrieved from core near the reservoir/caprock interface.
SACROC, Texas Special Thanks for providing the core to: