首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
This paper proposes a pressure-monitoring method to warn any possible CO2 leakage by monitoring pressure change at the upper layer of storage reservoirs within injection wells. The monitoring method is tested with two problems under various scenarios. With a current pressure detection limit, the proposed pressure-monitoring technique can be widely applicable wherever a permeable upper formation exists above the CO2 storage reservoir and is effective even in offshore storage sites wherever conventional monitoring methods for onshore sites cannot be applied. Meanwhile, the method is limited to apply during injection and is subject to any possible pressure dampening.  相似文献   

2.
One possible way of mitigating carbon dioxide (CO2) emissions from fossil fuel combustion is using carbon dioxide capture and storage (CCS) technology. However, public perception concerning CO2 storage in the geosphere is generally negative, being particularly motivated by perceived leakage risks. Therefore, a main issue when attempting to gain public acceptance is ensuring provision of appropriate monitoring practices, aimed at providing health, safety and environmental risk assessment, so that potential risks from CO2 storage are minimized. Naturally occurring CO2 deposits provide unique natural analogues for evaluating and validating methods used for the detection and monitoring of CO2 spreading and degassing into the atmosphere. Geological and hydrological structures of the Cheb Basin (NW Bohemia, Czech Republic) represent such a natural analogue for investigating CO2 leakage and offer a perfect location at which to verify monitoring tools used for direct investigation of processes along preferential migration paths. This shallow basin dating from the Tertiary age is characterized by up to 300?m thick Neogene sediment deposits and several tectonically active faults. The objectives of this paper are to introduce the CO2 analogues concept to present the Eger Rift as a suitable location for a natural CO2 analogue site and to demonstrate to what extent such an analogue site should be used (with a case study). The case study presents the results obtained from a joint application of geoelectrical measurements in combination with soil CO2 concentration and flux determination methods, for the detection and characterization of natural CO2 releases at gas seeps (as part of a hierarchic monitoring concept). To highlight discharge-controlling structural near surface features was the initial motivation for the application of geoelectrical measurements. Soil-gas concentration and flux measurement techniques are relatively simple to employ and are valuable methods that can be used to monitor seeping CO2 along preferential pathways. Joint interpretation of both approaches yields a first insight into fluid paths and reveals that the thickness and permeability of site-specific near surface sedimentary deposits have a great influence upon the spatial distribution of the CO2 degassing pattern at surface level.  相似文献   

3.
A small scale and temporally limited CO2 injection test was performed in a shallow aquifer to investigate the geochemical impact of CO2 upon such aquifers and to apply and verify different monitoring methods. Detailed site investigation coupled with multiphase simulations were necessary to design the injection experiment and to set up the monitoring network, before CO2 was injected over a ten-day period at three injection wells, at a depth of 18?m below surface level into a quaternary sand aquifer located close to the town of Wittstock in Northeast Germany. Monitoring methods comprised groundwater sampling and standard analyses, as well as trace element analyses and isotope analyses; geoelectrical borehole monitoring; passive samplers to analyse temporally integrated for cations and multi-parameter probes that can measure continuously for dissolved CO2, pH and electrical conductivity. Due to CO2 injection, total inorganic carbon concentrations increased and pH decreased down to a level of 5.1. Associated reactions comprised the release of major cations and trace elements. Geoelectrical monitoring, as well as isotope analyses and multi-parameter probes proved to be suitable methods for monitoring injected CO2 and/or the alteration of groundwater.  相似文献   

4.
Baseline monitoring at the proposed enhanced gas recovery site in Altmark (Germany) was carried out in combination with theoretical and laboratory investigations to describe and predict the principles of expected stable carbon isotope and dissolved inorganic carbon (DIC) trends during CO2 injection in reservoirs. This provides fundamental data for site-specific characterisation for monitoring purposes. Baseline ??13C values at the Altmark site ranged between ?1.8 and ?11.5??? and DIC values were about 2?mmol?L?1. These baseline values form the basis for a theoretical study on the influences of the ambient reservoir conditions on the state of geochemical and isotope equilibrium of the reservoir fluids. Transferring this theoretical study to the Altmark site enables predictions on geochemical trends during potential injection. Assuming that CO2 would be injected at the Altmark site to pCO2?=?100?bar and with a ??13C of ?30???, at isotopic and geochemical equilibrium, ??13CDIC values would approach this end-member, and DIC concentrations of 1,000?mmol L?1 would be expected. Laboratory experiments were conducted at low pCO2 levels (4?C35?bars) to mimic the approach of a CO2 plume at a monitoring well. These results support field investigations from other sites: that ??13CDIC is a sensitive tool for monitoring CO2 migration in the subsurface and simultaneously allows quantification of geochemical trapping of CO2.  相似文献   

5.
Potential pathways in the subsurface may allow upwardly migrating gaseous CO2 from deep geological storage formations to be released into near surface aquifers. Consequently, the availability of adequate methods for monitoring potential CO2 releases in both deep geological formations and the shallow subsurface is a prerequisite for the deployment of Carbon Capture and Storage technology. Geoelectrical surveys are carried out for monitoring a small-scale and temporally limited CO2 injection experiment in a pristine shallow aquifer system. Additionally, the feasibility of multiphase modeling was tested in order to describe both complex non-linear multiphase flow processes and the electrical behavior of partially saturated heterogeneous porous media. The suitability of geoelectrical methods for monitoring injected CO2 and geochemically altered groundwater was proven. At the test site, geoelectrical measurements reveal significant variations in electrical conductivity in the order of 15?C30?%. However, site-specific conditions (e.g., geological settings, groundwater composition) significantly influence variations in subsurface electrical conductivity and consequently, the feasibility of geoelectrical monitoring. The monitoring results provided initial information concerning gaseous CO2 migration and accumulation processes. Geoelectrical monitoring, in combination with multiphase modeling, was identified as a useful tool for understanding gas phase migration and mass transfer processes that occur due to CO2 intrusions in shallow aquifer systems.  相似文献   

6.
Careful site characterization is critical for successful geologic storage of carbon dioxide (CO2) because of the many physical and chemical processes impacting CO2 movement and containment under field conditions. Traditional site characterization techniques such as geological mapping, geophysical imaging, well logging, core analyses, and hydraulic well testing provide the basis for judging whether or not a site is suitable for CO2 storage. However, only through the injection and monitoring of CO2 itself can the coupling between buoyancy flow, geologic heterogeneity, and history-dependent multi-phase flow effects be observed and quantified. CO2 injection and monitoring can therefore provide a valuable addition to the site-characterization process. Additionally, careful monitoring and verification of CO2 plume development during the early stages of commercial operation should be performed to assess storage potential and demonstrate permanence. The Frio brine pilot, a research project located in Dayton, Texas (USA) is used as a case study to illustrate the concept of an iterative sequence in which traditional site characterization is used to prepare for CO2 injection and then CO2 injection itself is used to further site-characterization efforts, constrain geologic storage potential, and validate understanding of geochemical and hydrological processes. At the Frio brine pilot, in addition to traditional site-characterization techniques, CO2 movement in the subsurface is monitored by sampling fluid at an observation well, running CO2-saturation-sensitive well logs periodically in both injection and observation wells, imaging with crosswell seismic in the plane between the injection and observation wells, and obtaining vertical seismic profiles to monitor the CO2 plume as it migrates beyond the immediate vicinity of the wells. Numerical modeling plays a central role in integrating geological, geophysical, and hydrological field observations.  相似文献   

7.
Quick-look assessments to identify optimal CO2 EOR storage sites   总被引：1，自引：0，他引：1  
A newly developed, multistage quick-look methodology allows for the efficient screening of an unmanageably large number of reservoirs to generate a workable set of sites that closely match the requirements for optimal CO2 enhanced oil recovery (EOR) storage. The objective of the study is to quickly identify miscible CO2 EOR candidates in areas that contain thousands of reservoirs and to estimate additional oil recovery and sequestration capacities of selected top options through dimensionless modeling and reservoir characterization. Quick-look assessments indicate that the CO2 EOR resource potential along the US Gulf Coast is 4.7 billion barrels, and CO2 sequestration capacity is 2.6 billion metric tons. In the first stage, oil reservoirs are screened and ranked in terms of technical and practical feasibility for miscible CO2 EOR. The second stage provides quick estimates of CO2 EOR potential and sequestration capacities. In the third stage, a dimensionless group model is applied to a selected set of sites to improve the estimates of oil recovery and storage potential using appropriate inputs for rock and fluid properties, disregarding reservoir architecture and sweep design. The fourth stage validates and refines the results by simulating flow in a model that describes the internal architecture and fluid distribution in the reservoir. The stated approach both saves time and allows more resources to be applied to the best candidate sites.  相似文献   

8.
The injection of CO2 into depleted natural gas reservoirs has been proposed as a promising new technology for combining enhanced gas recovery and geological storage of CO2. During the injection, application of suitable techniques for monitoring of the induced changes in the subsurface is required. Observing the movement and the changes in saturation of the fluids contained in the reservoir and the confining strata is among the primary aims here. It is shown that under conditions similar to the Altmark site, Germany, pulsed neutron-gamma logging can be applied with limitations. The pulsed neutron-gamma method can be applied for detection and quantification of changes in brine saturation and water content, whereas changes in the gas composition are below the detection limit. A method to account for the effects of salt precipitation resulting from evaporation of residual brine is presented.  相似文献   

9.
In the context of carbon capture and storage, deep underground injection of CO2 induces the geomechanical changes within and around the injection zone and their impact on CO2 storage security should be evaluated. In this study, we conduct coupled multiphase fluid flow and geomechanical modeling to investigate such geomechanical changes, focusing on probabilistic analysis of injection-induced fracture reactivation (such as shear slip) that could lead to enhanced permeability and CO2 migration across otherwise low-permeability caprock formations. Fracture reactivation in terms of shear slip was analyzed by implicitly considering the fracture orientations generated using the Latin hypercube sampling method, in one case using published fracture statistics from a CO2 storage site. The analysis was conducted by a coupled multiphase fluid flow and geomechanical simulation to first calculate the three-dimensional stress evolution during a hypothetical CO2 injection operation and then evaluate the probability of shear slip considering the statistical fracture distribution and a Coulomb failure analysis. We evaluate the probability of shear slip at different points within the injection zone and in the caprock just above the injection zone and relate this to the potential for opening of new flow paths through the caprock. Our analysis showed that a reverse faulting stress field would be most favorable for avoiding fracture shear reactivation, but site-specific analyses will be required because of strong dependency of the local stress field and fracture orientations.  相似文献   

10.
This paper introduces an integrative hierarchical monitoring concept allowing for the detection and assessment of possible leakages from geological storage formations into the shallow subsurface or atmosphere. The concept introduced in this paper combines various investigation methods working at different scales and with varying resolutions. This approach will allow large spatial areas to be consistently covered, to enable efficient monitoring. Experience gained from the adoption of these tools for naturally occurring CO2 deposits (analogue sites) is helpful for the evaluation and adoption of the methods to the requirements of storage projects.  相似文献   

11.
Numerical simulations of CO2 migration for the period June 2008–December 2011 were performed based on a unique data set including a recently revised static geological 3D model of the reservoir formation of the Ketzin pilot site in Brandenburg, Germany. We applied the industrial standard ECLIPSE 100 and scientific TOUGH2-MP simulators for this task and implemented a workflow to allow for integration of complex model geometries from the Petrel software package into TOUGH2-MP. Definition of a near- and a far-field well area allowed us to apply suitable permeability modifiers, and thus to successfully match simulation results with pressure measurements and arrival times in observation wells. Coincidence was achieved for CO2 arrival times with deviations in the range of 5.5–15 % and pressure values in the injection well CO2 Ktzi 201/2007 and the observation well CO2 Ktzi 202/2007 with even smaller deviations. It is shown that the integration of unique operational and observation data in the workflow improves the setup of the geological model. Within such an iteration loop model uncertainties are reduced and enable advanced predictions for future reservoir behaviour with regard to pressure development and CO2 plume migration in the storage formation at the Ketzin pilot site supporting the implementation of monitoring campaigns and guiding site operation.  相似文献   

12.
The Ketzin pilot site, led by the GFZ German Research Centre for Geosciences, is Europe??s longest-operating on-shore CO2 storage site with the aim of increasing the understanding of geological storage of CO2 in saline aquifers. Located near Berlin, the Ketzin pilot site is an in situ laboratory for CO2 storage in an anticlinal structure in the Northeast German Basin. Starting research within the framework of the EU project CO2SINK in 2004, Ketzin is Germany??s first CO2 storage site and fully in use since the injection began in June 2008. After 39?months of operation, about 53,000 tonnes of CO2 have been stored in 630?C650?m deep sandstone units of the Upper Triassic Stuttgart Formation. An extensive monitoring program integrates geological, geophysical and geochemical investigations at Ketzin for a comprehensive characterization of the reservoir and the CO2 migration at various scales. Integrating a unique field and laboratory data set, both static geological modeling and dynamic simulations are regularly updated. The Ketzin project successfully demonstrates CO2 storage in a saline aquifer on a research scale. The results of monitoring and modeling can be summarized as follows: (1) Since the start of the CO2 injection in June 2008, the operation has been running reliably and safely. (2) Downhole pressure data prove correlation between the injection rate and the reservoir pressure and indicates the presence of an overall dynamic equilibrium within the reservoir. (3) The extensive geochemical and geophysical monitoring program is capable of detecting CO2 on different scales and gives no indication for any leakage. (4) Numerical simulations (history matching) are in good agreement with the monitoring results.  相似文献   

13.
Our study at this natural analog site contributes to the evaluation of methods within a hierarchical monitoring concept suited for the control of CO2 degassing. It supports the development of an effective monitoring concept for geological CO2 storage sites—carbon capture and storage as one of the pillars of the European climate change efforts. This study presents results of comprehensive investigations along a 500-m long profile within the Hartou?ov (Czech Republic) natural CO2 degassing site and gives structural information about the subsurface and interaction processes in relation to parameters measured. Measurements of CO2 concentrations and investigation of the subsurface using electrical resistivity tomography and self-potential methods provide information about subsurface properties. For their successful application it is necessary to take seasonal variations (e.g., soil moisture, temperature, meteorological conditions) into consideration due to their influence on these parameters. Locations of high CO2 concentration in shallow depths are related to positive self-potential anomalies, low soil moistures and high resistivity distributions, as well as high δ13C values and increased radon concentrations. CO2 ascends from deep geological sources via preferential pathways and accumulates in coarser sediments. Repetition of measurements (which includes the effects of seasonal variations) revealed similar trends and allows us to identify a clear, prominent zone of anomalous values. Coarser unconsolidated sedimentary layers are beneficial for the accumulation of CO2 gas. The distribution of such shallow geological structures needs to be considered as a significant environmental risk potential whenever sudden degassing of large gas volumes occurs.  相似文献   

14.
A controlled field pilot has been developed in Bozeman, Montana, USA, to study near surface CO2 transport and detection technologies. A slotted horizontal well divided into six zones was installed in the shallow subsurface. The scale and CO2 release rates were chosen to be relevant to developing monitoring strategies for geological carbon storage. The field site was characterized before injection, and CO2 transport and concentrations in saturated soil and the vadose zone were modeled. Controlled releases of CO2 from the horizontal well were performed in the summers of 2007 and 2008, and collaborators from six national labs, three universities, and the U.S. Geological Survey investigated movement of CO2 through the soil, water, plants, and air with a wide range of near surface detection techniques. An overview of these results will be presented.  相似文献   

15.
Pressure buildup limits CO2 injectivity and storage capacity and pressure loss limits the brine production capacity and security, particularly for closed and semi-closed formations. In this study, we conduct a multiwell model to examine the potential advantages of combined exhaustive brine production and complete CO2 storage in deep saline formations in the Jiangling Depression, Jianghan Basin of China. Simulation results show that the simultaneous brine extraction and CO2 storage in saline formation not only effectively regulate near-wellbore and regional pressure of storage formation, but also can significantly enhance brine production capacity and CO2 injectivity as well as storage capacity, thereby achieving maximum utilization of underground space. In addition, the combination of brine production and CO2 injection can effectively mitigate the leakage risk between the geological units. With regard to the scheme of brine production and CO2 injection, constant pressure injection is much superior to constant rate injection thanks to the mutual enhancement effect. The simultaneous brine production of nine wells and CO2 injection of four wells under the constant pressure injection scheme act best in all respects of pressure regulation, brine production efficiency, CO2 injectivity and storage capacity as well as leakage risk mitigation. Several ways to further optimize the combined strategy are investigated and the results show that increasing the injection pressure and adopting fully penetrating production wells can further significantly enhance the combined efficiency; however, there is no obvious promoting effect by shortening the well spacing and changing the well placement.  相似文献   

16.
In order to detect hydraulic and geochemical impact on the groundwater directly above the CO2 storage reservoir at the Ketzin pilot site continuous monitoring using an observation well is carried out. The target depth (446 m below ground level, bgl.) of the well is the Exter formation (Upper Triassic, Rhaetian) which is the closest permeable stratigraphic overlying formation to the CO2 storage reservoir (630–636 m bgl. at well location). The monitoring concept comprises evaluation of hydraulic conditions, temperature, water chemistry, gas geochemistry and δ13C values. This is achieved by a tubing inserted inside the well with installed pressure sensors and a U-tube sampling system so that pumping tests or additional wireline logging can be carried out simultaneously with monitoring. The aquifer was examined using a pump test. The observation well is hydraulically connected to the regional aquifer system and the permeability of about 1.8 D is comparatively high. Between Sept. 2011 and Oct. 2012, a pressure increase of 7.4 kPa is observed during monitoring under environmental conditions. Drilling was carried out with drilling mud on carbonate basis. The concentration of residual drilling mud decreases during the pump test, but all samples show a residual concentration of drilling mud. The formation fluid composition is recalculated with PHREEQC and is comparable to the literature values for the Exter formation. The gas partial pressure is below saturation at standard conditions and the composition is dominated by N2 similar to the underlying storage reservoir prior to CO2 injection. The impact of residual drilling mud on dissolved inorganic carbon and the respective δ13C values decreases during the monitoring period. The pristine isotopic composition cannot be determined due to calcite precipitation. No conclusive results indicate a leakage from the underlying CO2 storage reservoir.  相似文献   

17.
Structural traps like anticline structures are preferred for carbon dioxide sequestration as they limit lateral spreading of CO2 and thus provide localized storage. This study, therefore, assesses strategies for maximizing storage of CO2 using as hypothetical but realistic storage site a typical anticline structure in the North German sedimentary basin. Scenario simulations are performed to investigate the effects of well number, location, spacing and alignment, using fracture pressure and containment of CO2 within the anticline as constraining factors. Scenarios are ranked by stored CO2 mass, pressure increase due to injection and CO2 immobilized by dissolution or residual trapping. It is found that pressure overlap from different injectors influences CO2 migration considerably, limiting the storable amount to about 150 Mt, which represents half of the static capacity estimate.  相似文献   

18.
Carbon sequestration in shallow aquifers can be facilitated by water withdrawal. The factors that optimize the injection/withdrawal balance to minimize potential environmental impacts have been studied, including reservoir size, well pattern, injection rate, reservoir heterogeneity, anisotropy ratio, and permeability sequence. The effects of these factors on CO2 storage capacity and efficiency were studied using a compositional simulator Computer Modeling Group-General Equation of State Model, which modeled features including residual gas trapping, CO2 solubility, and mineralization reactions. Two terms, storage efficiency and CO2 relative breakthrough time, were introduced to better describe the problem. The simulation results show that simultaneous water withdrawal during CO2 injection greatly improves CO2 storage capacity and efficiency. A certain degree of heterogeneity or anisotropy benefits CO2 storage. A high injection rate favors storage capacity, but reduces the storage efficiency and CO2 breakthrough time, which in turn limits the total amount of CO2 injected.  相似文献   

19.
The measurement of concentrations of volatile species in soil gases has potential for use in geochemical exploration for concealed ore deposits and for monitoring of subsurface contaminants. However, the interpretation of anomalies in surficial gases can be difficult because soil-gas concentrations are dependent on both meteorological and environmental conditions.For this study, concentrations of He, CO2, O2 and N2 and meteorological conditions were monitored for 10–14 months at eight nonmineralized sites in both humid and dry environments. Gases were collected at 0.6–0.7-m depth at seven sites. At one site, gases were collected from 0.3-, 0.6-, 1.2-, and 2.0-m depths; diurnal monitoring studies were conducted at this site also. Rain and snowfall, soil and air temperatures, barometric pressure, and relative humidity were monitored at all the sites. The sand, silt and clay content, and the organic carbon content of surficial soil were measured at each site.Meteorological conditions generally affected He and CO2 concentrations in the same way at all the sites; however, these effects were modified by local environmental conditions. Both seasonal and diurnal concentration changes occurred. The most important seasonal concentration changes were related to rain and snowfall and soil and air temperatures. Seasonal changes tended to be larger then the diurnal changes, but both could be related to the same processes. Local conditions of soil type and organic content affected the amount of pore space and moisture present in the soil and therefore the soil-gas concentrations.  相似文献   

20.
With heightened concerns on CO2 emissions from pulverized-coal (PC) power plants, there has been major emphasis in recent years on the development of safe and economical geological carbon sequestration (GCS) technology. Saline aquifers are considered very attractive for GCS because of their large storage capacity in U.S. and other parts of the world for long-term sequestration. However, uncertainties about storage efficiency as well as leakage risks remain major areas of concern that need to be addressed before the saline aquifers can be fully exploited for carbon sequestration. A genetic algorithm-based optimizer has been developed and coupled with the well-known multiphase numerical solver TOUGH2 to optimally examine various injection strategies for increasing the CO2 storage efficiency as well as for reducing its plume migration. The optimal injection strategies for CO2 injection employing a vertical injection well and a horizontal injection well are considered. To ensure the accuracy of the results, the combined hybrid numerical solver/optimizer code was validated by conducting simulations of three widely used benchmark problems employed by carbon sequestration researchers worldwide. The validated code is then employed to optimize the proposed water-alternating-gas injection scheme for CO2 sequestration using both the vertical and the horizontal injection wells. The results suggest the potential benefits of CO2 migration control and dissolution. The optimization capability of the hybrid code holds a great promise in studying a host of other problems in GCS, namely how to optimally enhance capillary trapping, accelerate the dissolution of CO2 in water or brine, and immobilize the CO2 plume.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号