International Journal of Greenhouse Gas Control最新文献

We present the first local micro-seismicity catalogue including focal mechanisms for the Hontomín plant, the only site of its kind in Spain and one of the very scarce CO₂ storage facilities in Europe. The catalogue reveals a correlation between micro-seismicity occurrence and bottom hole pressure (BHP) at the injection well. A burst of micro-seismicity ranging from -1 to 0.4 M_L, thus imperceptible to human senses, took place coeval with the longest duration test of the period studied when the BHP was the highest. Events clustered at ∼ 0.4 km below the well bottom hole. Focal mechanisms could be well resolved for 3 events with similar results, showing a strong strike-slip component and a minor reverse component, with similarly oriented nodal planes. The local stress fields inverted from the focal mechanism solutions exhibit an orientation of the maximum horizontal stress axis (S_Hmax) that ranges from NE to ESE and differs from the principal stress orientations obtained in previous works for the same area. The micro-seismicity locations and tensors obtained are useful inputs to models aiming to better understand the deformation effects of fluids’ injection underground.

Many nations have pledged to reach carbon neutrality by 2050. Embarking on the decarbonization journey, they posited geological carbon storage (GCS) as a pivotal technology within the carbon capture, utilization, and storage (CCUS) framework. The CCUS chain operates to reduce “hard-to-abate” emissions at key sectors by capturing carbon dioxide (CO₂), reusing it, transporting it, or disposing of it via injection into underground geological formations for permanent storage. Despite the global success of GCS ventures, mainly driven by the oil and gas industry, GCS initiatives are still in their early stages in several developing countries. In Brazil, for instance, a full setup covering precise storage capacity databases, potential CCUS clusters, national regulatory structure, and auxiliary computer-aided engineering is underway. Intended to push the frontier in the latter subject, this paper introduces mathematical models for qualifying underground CO₂ storage sites. Our research explores a family of multivariate functionals endowed with underlying reservoir features and distinct weighting functions, thus envisioning two primary objectives. Firstly, it clarifies non-linear interactions between rock and fluid properties using quality indicators. Secondly, it evaluates geographical regions considering structural traps/caprocks settings. Backed by the Matlab Reservoir Simulation Toolbox (MRST) capabilities, the methodology is a subsidiary resource for identifying suitable injection and storage sites. A case study using the UNISIM-I-D model generated dozens of volumetric quality maps that point to unique potential storage sites. Numerical simulation experiments of injection comparing legacy and novel wells reveal storage surpluses improved by up to 50%. The paper seeks to establish foundational knowledge in GCS efficiency for general underground settings. One expects that these outcomes leverage well-repurposing perspectives and stimulate field appraisal actions to scale up GCS projects both in Brazil and worldwide.

Mechanical properties of caprock are important for subsurface energy sequestration as they determine the rock stability under the influence of external forces. Despite some advantages, there is a lack of knowledge regarding the interplay between rock texture and mechanical properties and their impact on the caprock stability within a short-term fluid-rock reaction period. Typical caprock samples from the Mercia Mudstone Group in the East Irish Sea Basin are studied in this work. X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) were used to identify minerology and local heterogeneity characteristics. Nanoindentation tests were conducted before and after CO₂-brine-rock reaction to investigate the changes of micro-mechanical properties. After CO₂-brine treatment, significant dolomite dissolution was observed in all samples (although dolomite content was only minor in some samples). In contrast, the micro-texture of other minerals showed no significant changes indicating minimal to no dissolution at the current resolution. The changes of mechanical properties are lower than expected, which are probably related to the impaired cementation induced by the retained water in pore throats and relatively rough surface after reaction. For long-term carbon sequestration, the layered depositional characteristics of different phases may not only form a barrier to prevent fluids leaking upward, but also complement each other in mechanical properties to maintain stability. This study improves the understanding of the effect of microscale structural and micro-mechanical changes on caprock stability in carbon sequestration related applications.

The utilization of depleted gas reservoirs for carbon storage offers substantial advantages. However, it raises concerns related to the geomechanical effects of historic gas extraction on the CO₂ sequestration operation. In this study, a coupled thermo-hydro-mechanical investigation is conducted on a multi-layered sedimentary system that includes sealed bounding faults. Our simulations exhibit various levels of reservoir compaction during gas extraction under different pre-consolidation conditions of the sediments, highlighting the pivotal role of reservoir compaction in geomechanical analysis. The results demonstrate the occurrence of strain-hardening compaction behavior in the reservoir during post-yield depletion. This compaction is accompanied by a significant reduction in porosity and permeability, as well as irreversible surface subsidence. Hysteresis in the stress state is induced by the aforementioned irreversible reservoir compaction through two primary mechanisms: poro-elastoplastic stressing and differential compaction on each side of the sealing fault. These mechanisms alter the magnitude and orientation of stress inside and outside the depleted reservoir. Moreover, caprock compaction is impeded and delayed by the irreversible reservoir compaction owing to poro-elastoplastic stressing. This implies that conventional methods relying on the poro-elasticity theory alone may overestimate pressure required to fracture the caprock by approximately 2 MPa. When considering the combined effect of poro-elastoplastic stressing and differential compaction, neglecting irreversible reservoir compaction may lead to underestimation of the critical pressure for inducing fault slip by up to 4.9 MPa. Additionally, regardless of whether plastic void compaction is considered, we recommend increased attention be focused on the sub-vertical faults to mitigate the risk of significant slip that potentially could also lead to upward CO₂ leakage. In scenarios where a slip event occurs in a fault during reservoir depletion, the results show that a subsequent CO₂ injection operation tends to stabilize the faults. Nevertheless, it is crucial to consider that fault stability could deteriorate rapidly over time, potentially leading to a second slip event during carbon sequestration.

Carbon capture and storage with enhanced oil recovery (CCS-EOR) technology plays a crucial role in achieving dual carbon targets in China. And the rapid diffusion of technology requires collaboration among various stakeholders involved in industrial chain of CCS-EOR project and then it will cause conflict of interest among the participants. In order to solve the problem existing in CCS-EOR promotion and propel the rapid deployment of low-carbon technology in China, the paper constructs a tripartite evolutionary game model by incorporating the strategic choices of coal-fired power plants, oilfield enterprises and governments into the framework, explores the respective dynamic evolutionary path of three parties and analyzes the impact of each parameter change on the system evolution results Through the numerical simulation, the paper identifies the optimal evolutionary path to spur the application of CCS-EOR and determine their strategy choices of three involved subjects in the game framework. Based on the sensitivity analysis, results are given as follows: (1) The government's clean electricity subsidy and carbon utilization subsidy have pushed the timing of CCS retrofitting significantly forward, but the initial investment subsidy has little impact on it; (2) Under the cooperation mode of coal-fired power plants and oilfield enterprises, the optimal cost-sharing ratio of the initial investment for coal-fired power plants is about 0.4 to promote both sides to reach cooperation faster. Once it exceeds 0.4, the probability of cooperation between them will be significantly reduced; (3) The carbon tax policy effectively propels the development of CCS-EOR technology. When the carbon tax rises from 30 CNY/t to 120CNY/t, power plants will conduct CCS retrofitting investment two years in advance.

Countries are considering different options to achieve net zero emissions including Bioenergy with carbon capture and storage (BECCS), which is the process of capturing and storing CO₂ from processes that use bioenergy to produce heat, electricity, or biofuels. However, this technology faces sustainability concerns and possesses complex value chains of its emissions. Adding further to this complexity, the literature indicates two opposing views with respect to the potential of BECCS in terms of being able (or unable) to achieve negative emissions. Hence, this paper analyzes in detail a wide range of BECCS pathways in terms of their ability to achieve negative emissions along with their associated costs. Out of seven assessed pathways, our analysis shows that corn to ethanol and biomethane production from maize BECCS pathway in the USA, biomethane production from wet manure in Europe, and baling of straw pellets with trans-Atlantic shipment can achieve negative emissions at a cost of 50, 108, 159, and 232 dollars per ton of CO₂ ($/tCO₂) respectively. Other technologies like poplar pellets, forest residue, and agricultural residue with trans-Atlantic shipment are not able to achieve negative emissions.

Permeability variations due to sedimentological heterogeneity are important in controlling CO₂ migration pathways, CO₂ plume dynamics, and stratigraphic, capillary and dissolution trapping of CO₂ in subsurface storage units and complexes. Thus, knowing these parameters is crucial to developing a CO₂ injection strategy that maximizes storage and trapping efficiency. In this study we analyzed the sedimentological and permeability heterogeneity of the Bunter Sandstone Formation at the Endurance CO₂ storage site, offshore UK, through integrated facies analysis, minipermeameter measurements, and thin section analysis. Detailed core logging and outcrop analysis were performed to identify facies and related heterogeneities. Twelve lithofacies have been identified in cores. By analyzing the stacking patterns of the facies, three facies associations and three architectural elements were identified in cores and outcrop analogues, respectively. Heterogeneities occur at all the scales ranging from mm-scale laminae to 10′s m-scale architectural elements.

Permeability variations at outcrop and in core are closely related to sedimentological heterogeneities. Minipermeameter and core plug permeability data show up to three orders of magnitude variation across the facies. Cross-bedded (Sp, St, Sl, Spmc) and structureless (Sm) sandstones are the most permeable (4–5400 mD) facies, whereas pebbly conglomerates (Gmg) and laminated mudstones (Fl) are least permeable (0.18–89 mD) facies. Mottled and deformed sandstone (Smd) and crinkly laminated sandstone (Sc) have highly variable permeability (0.69–480 mD). Minipermeameter data reveal permeability varies by a factor of five at centimeter scale within planar cross-bedded (Sp), trough cross-bedded (St) and planar bedded sandstone (Sh) sandstone facies, while planar cross-bedded sandstone with mud clasts along foresets (Spmc) exhibit permeability variation up to a factor of four. Petrographic analysis of thin sections shows that these permeability variations are related to changes in grain size, clay content, and distribution of dolomite cements.

Structural trapping provided by seals is one of the key components of CO₂ geological storage systems. Clay-rich caprocks and fault gouge are expected to be water-wet at supercritical CO₂ conditions and to create a positive capillary pressure $P_{C{O}_2}-P_w>0$MPa to ensure trapping of buoyant CO₂. This paper presents the results of water imbibition experiments in resedimented clay mudrocks immersed in supercritical CO₂ at temperature T ≥ 60 °C and pressure $P_{C{O}_2}$ ≥ 25 MPa. The samples used in this work include kaolinite clay and Anahuac shale from the Gulf of Mexico Coast. Additional validation tests include Berea sandstone and silane-treated Berea sandstone. The results show spontaneous and rapid imbibition of water droplets into resedimented and rock samples initially saturated with wet supercritical CO₂ for all cases. This outcome provides indirect evidence that typical siliciclastic caprock building minerals remain water-wet to CO₂ at typical storage pressure and temperature conditions. The results and analysis indicate that siliciclastic caprock and fault gouge are expected to develop a positive capillary entry and breakthrough pressure to hold buoyant CO₂ by capillary forces. These results validate expectations of buoyant CO₂ structural trapping and field observations from natural analogues.

Carbon dioxide capture and storage (CCS), the bottom covering technology for environmental protection and energy transformation, plays a vital role in reducing CO₂ emissions and has become an international research hotspot. The safe operation of CO₂ transport infrastructure is crucial to ensure the smooth implementation of carbon reduction actions. However, the understanding of disasters in carbon transmission infrastructure is not comprehensive and profound enough since CCS is still developing, which leads to few engineering standards on disaster prevention and mitigation of CO₂ transport infrastructure. This paper provides detailed reviews, including the composition and characteristics of carbon transmission infrastructure, failure mechanisms. It is concluded that the characteristics of CO₂ transport infrastructure damage fundamentally stems from the working fluid and environment, and novelty pointed out that future research hotspots are damage under multi-field coupling, damage detection and monitoring, design to reduce damage and repair after damage. The summary of existing research will be helpful for future academic research and engineering practice of CO₂ transport infrastructure disaster prevention and mitigation.

Designs for Risk Evaluation and Management (DREAM) is a tool developed under the National Risk Assessment Partnership (NRAP) to enhance geologic carbon storage safety and efficiency. Using potential leakage scenarios generated externally by the users preferred history-matching approach, DREAM constructs ideal combinations of sensor locations in the right place at the right time to detect as many leaks as possible, detect them as early as possible, and minimize cost. This user-friendly tool, developed in Java, features a window-based GUI for input and a 3D visualization tool for viewing the domain space and optimized monitoring plans. DREAM's latest version accommodates real-world usage by allowing for joint optimization of wellbore point sensor placements and surface geophysics survey geometries, and by using more efficient multi-objective optimization algorithms. In an example shown here, these two improvements combined allow us to support containment assurance and go from detecting 80–90 % of the potential CO₂ leakage to +99.7 %, a step-change improvement that can make the deciding difference in whether a site is suitable for geologic carbon storage. Though developed for geologic carbon storage, this tool would be equally applicable in many surface or offshore environmental monitoring projects.