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Yang, Changbing

Publications and source records attributed to Yang, Changbing.

18 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Reactive chemical transport simulations of geologic carbon sequestration: Methods and applications

Chemical reaction simulations are considerably used to quantitatively assess the long-term geologic carbon sequestration (GCS), such as CO 2 sequestration capacity estimations, leakage pathway analyses, enhanced oil recovery (EOR) efficiency studies, and risk assessments of sealing formations (caprocks), wellbores, and overlying underground water resources. All these require a deep understanding of the CO 2 - associated chemical reactions. To ensure long-term, safe CO 2 sequestration in the intended formations, modeling is the only way to plausibly assess the CO 2 flow, reaction, and transport over thousands of years. This review summarizes the multiple methodologies for describing homogeneous and heterogeneous chemical reaction patterns and multiscale application examples, the recent progress and current status of chemical reaction simulations for GCS, and the impact of such simulations on geological CO2 sequestration performance. Technical gaps and future challenges are also discussed for further study. The trends and challenges of such studies include: (1) the combination of coupled chemical, mechanical, and transport processes with calibrated experiments and associated uncertainty/risk assessments; (2) enhancement of the ability to simulate detailed geophysical and geochemical equations to mimic in situ conditions; and (3) characterization of multiscale subsurface systems with detailed conceptual models and assignment of suitable boundary conditions for field-scale sequestration fields. One major gap remaining is the current lack of accurate (and scale-justified) kinetic and equilibrium chemical reaction parameters under reservoir conditions. Advanced models that couple chemical, mechanical, and transport processes with scale-justified parameters, from lab to field-scale experiments, are required for quantitative assessments of sequestration capacity and the long-term safety of GCS projects.

58 GEOSCIENCES↗
DOE OSTI2018

Heterogeneity-assisted carbon dioxide storage in marine sediments

Global climate change is a pressing problem caused by the accumulation of anthropogenic greenhouse gas emissions in the atmosphere. Carbon dioxide (CO 2 ) capture and storage is a promising component of a portfolio of options to stabilize atmospheric CO 2 concentrations. Meaningful capture and storage requires the permanent isolation of enormous amounts of CO 2 away from the atmosphere. In this paper, we investigate the effectiveness of heterogeneity-induced trapping mechanism, in potential synergy with a self-sealing gravitational trapping mechanism, for secure CO 2 storage in marine sediments. We conduct the first comprehensive study on heterogeneous marine sediments with various thicknesses at various ocean depths. Prior studies of gravitational trapping have assumed homogeneous (deep-sea) sediments, but numerous studies suggest reservoir heterogeneity may enhance CO 2 trapping. Heterogeneity can deter the upward migration of CO 2 and prevent leakage through the seafloor into the seawater. Using geostatistically-based Monte Carlo simulations of CO 2 transport in heterogeneous sediment, we show that strong spatial variability in permeability is a dominant physical mechanism for secure CO 2 storage in marine sediments below 1.2 km water depth (less than half of the depth needed for the gravitational trapping). We identify thresholds for sediment thickness, mean permeability and porosity, and their relationships to meaningful injection rates. Our results for the U.S. Gulf of Mexico suggest that heterogeneity-assisted trapping has a greater areal extent with more than three times the CO 2 storage capacity for secure offshore CO 2 storage than with gravitational trapping. Finally, these characteristics offer CO 2 storage opportunities that are closer to coasts, more accessible, and likely to be less costly.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Injectivity Evaluation for Offshore CO 2 Sequestration in Marine Sediments

Global and regional climate change caused by greenhouse gases emissions has stimulated interest in developing various technologies (such as carbon dioxide (CO 2 ) geologic sequestration in brine reservoirs) to reduce the concentrations of CO 2 in the atmosphere. Our study develops a statistical framework to identify gravitational CO 2 trapping processes and to quantitatively evaluate both CO 2 injectivity (or storage capacity) and leakage potential from marine sediments which exhibit heterogeneous permeability and variable thicknesses. Here, we focus on sets of geostatistically-based heterogeneous models populated with fluid flow parameters from several reservoir sites in the U.S. Gulf of Mexico (GOM). A computationally efficient uncertainty quantification study was conducted with results suggesting that permeability heterogeneity and anisotropy, seawater depth, and sediment thickness can all significantly impact CO 2 flow and trapping. Large permeability/porosity heterogeneity can enhance gravitational, capillary, and dissolution trapping, which acts to deter CO 2 upward migration and subsequent leakage onto the seafloor. When log permeability variance is 5, self-sealing with heterogeneity-enhanced gravitation trapping can be achieved even when water depth is 1.2 km. This extends the previously identified self-sealing condition that water depth be greater than 2.7 km. Our results have yielded valuable insight into the conditions under which safe storage of CO 2 can be achieved in offshore environments. The developed statistical framework is general and can be adapted to study other offshore sites worldwide.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

CO 2 Sequestration and Enhanced Oil Recovery at Depleted Oil/Gas Reservoirs

This study presents a quantitative evaluation of the operational and technical risks of an active CO 2 -EOR project. A set of risk factor metrics is defined to post-process the Monte Carlo (MC) simulations for statistical analysis. The risk factors are expressed as measurable quantities that can be used to gain insight into project risk (e.g. environmental and economic risks) without the need to generate a rigorous consequence structure, which include (a) CO 2 injection rate, (b) net CO 2 injection rate, (c) cumulative CO 2 storage, (d) cumulative water injection, (e) oil production rate, (f) cumulative oil production, (g) cumulative CH 4 production, and (h) CO 2 breakthrough time. The Morrow reservoir at the Farnsworth Unit (FWU) site, Texas, is used as an example for studying the multi-scale statistical approach for CO 2 accounting and risk analysis. A set of geostatistical-based MC simulations of CO 2 -oil/gas-water flow and transport in the Morrow formation are conducted for evaluating the risk metrics. A response-surface-based economic model has been derived to calculate the CO 2 -EOR profitability for the FWU site with a current oil price, which suggests that approximately 31% of the 1000 realizations can be profitable. If government carbon-tax credits are available, or the oil price goes up or CO 2 capture and operating expenses reduce, more realizations would be profitable.

02 PETROLEUM↗
DOE OSTI2017

Quantitative assessment of soil CO 2 concentration and stable carbon isotope for leakage detection at geological carbon sequestration sites

This paper presents a quantitative method to evaluate CO 2 concentration ([CO 2 ]) and stable carbon isotope ratio (δ 13 C) as indicators for leakage detection at a geological carbon sequestration site by combining use of field release tests and a numerical modeling approach. A numerical model was developed to simulate CO 2 dynamics by considering diffusion, dissolution in soil water, and soil respiration. The numerical model fits the background dynamics of [CO 2 ] (360 to 550 ppm) and δ 13 C (-16‰ to -6‰) well and reproduces fairly the overall trend observed during the CO 2 release test. The model was further applied to assess detection probability (DP) of [CO 2 ] and δ 13 C for leakage detection in terms of various factors, such as CO 2 leakage rate, background variations, δ 13 C of the CO 2 leaked, and the threshold value of signal-to-noise ratio. Modeling results suggest that δ 13 C may have a higher DP than [CO 2 ]. This study also shows that DP of δ 13 C for the IEA Weyburn project is close to 0, implying δ 13 C is inappropriate to be an indicator for CO 2 leakage at the site. Finally, the quantitative method developed can also be used to design a monitoring plan or strategy in a near-surface environment for geological carbon sequestration.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

CO 2 Accounting and Risk Analysis for CO 2 Sequestration at Enhanced Oil Recovery Sites

Using CO2 in enhanced oil recovery (CO2-EOR) is a promising technology for emissions management because CO2-EOR can dramatically reduce sequestration costs in the absence of emissions policies that include incentives for carbon capture and storage. This study develops a multiscale statistical framework to perform CO2 accounting and risk analysis in an EOR environment at the Farnsworth Unit (FWU), Texas. A set of geostatistical- based Monte Carlo simulations of CO2-oil/gas-water flow and transport in the Morrow formation are conducted for global sensitivity and statistical analysis of the major risk metrics: CO2/water injection/production rates, cumulative net CO2 storage, cumulative oil/gas productions, and CO2 breakthrough time. The median and confidence intervals are estimated for quantifying uncertainty ranges of the risk metrics. A response-surface-based economic model has been derived to calculate the CO2-EOR profitability for the FWU site with a current oil price, which suggests that approximately 31% of the 1000 realizations can be profitable. If government carbon-tax credits are available, or the oil price goes up or CO2 capture and operating expenses reduce, more realizations would be profitable. The results from this study provide valuable insights for understanding CO2 storage potential and the corresponding environmental and economic risks of commercial-scale CO2- sequestration in depleted reservoirs.

Dai, Zhenxue↗
DOE OSTI2016

Reactive transport modeling of the enhancement of density-driven CO 2 convective mixing in carbonate aquifers and its potential implication on geological carbon sequestration

We study the convection and mixing of CO 2 in a brine aquifer, where the spread of dissolved CO 2 is enhanced because of geochemical reactions with the host formations (calcite and dolomite), in addition to the extensively studied, buoyancy-driven mixing. The nonlinear convection is investigated under the assumptions of instantaneous chemical equilibrium, and that the dissipation of carbonate rocks solely depends on flow and transport and chemical speciation depends only on the equilibrium thermodynamics of the chemical system. The extent of convection is quantified in term of the CO 2 saturation volume of the storage formation. Our results suggest that the density increase of resident species causes significant enhancement in CO 2 dissolution, although no significant porosity and permeability alterations are observed. Furthermore, early saturation of the reservoir can have negative impact on CO 2 sequestration.

58 GEOSCIENCES↗
DOE OSTI2015

Southeast Regional Carbon Sequestration Partnership (SECARB): Analyze Data Collected, Revise Surface Monitoring Plan to Maximize Benefit and Continue Data Collection

Objectives of the shallow groundwater study at the Cranfield site since 2008, as a part of the SECARB Phase III early test, were to 1) assess potential impacts of CO 2 leakage on groundwater quality; and 2) test and develop monitoring technologies for CO 2 leakage detection. The study did not intend to seek CO2 leakage signals via monitoring groundwater chemistry in the Cranfield shallow aquifer. Instead, quarterly or semi-annually groundwater sampling from the shallow aquifer was used to characterize spatial and temporal variations in geochemical parameters because CO 2 injection into the deep reservoir started in 2008.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2014

Field Demonstration of CO 2 Leakage Detection in Potable Aquifers with a Pulselike CO 2 -Release Test

Here, this study presents two field pulse-like CO 2 -release tests to demonstrate CO 2 leakage detection in a shallow aquifer by monitoring groundwater pH, alkalinity and dissolved inorganic carbon (DIC) using the periodic groundwater sampling method and a fiber-optic CO 2 sensor for real-time in situ monitoring of dissolved CO 2 in groundwater. Measurements of groundwater pH, alkalinity, DIC and dissolved CO 2 clearly deviated from their background values, showing responses to CO 2 leakage. Dissolved CO 2 observed in the tests was highly sensitive in comparison to groundwater pH, DIC, and alkalinity. Comparison of the pulse-like CO 2 -release tests to other field tests suggests that pulse-like CO 2 -release tests can provide reliable assessment of geochemical parameters indicative of CO 2 leakage. Measurements by the fiber-optic CO 2 sensor, showing obvious leakage signals, demonstrated the potential of real-time in situ monitoring of dissolved CO 2 for leakage detection at a GCS site. Results of a two-dimensional reactive transport model reproduced the geochemical measurements and confirmed that the decrease in groundwater pH and the increases in DIC and dissolved CO 2 observed in the pulse-like CO 2 -release tests were caused by dissolution of CO 2 whereas alkalinity was likely affected by carbonate dissolution.

54 ENVIRONMENTAL SCIENCES↗