Geothermo-mechanical alterations due to heat energy extraction in enhanced geothermal systems: Overview and prospective directions

Geothermal energy from deep underground (or geological) formations,with or without its combination with carbon capture and storage (CCS),can be a key technology to mitigate anthropogenic greenhouse gas emissions and meet the 2050 net‐zero carbon emission target.Geothermal resources in low‐permeability and medium‐and high‐temperature reservoirs in sedimentary sequence require hydraulic stimulation for enhanced geothermal systems (EGS).However,fluid migration for geothermal energy in EGS or with potential CO_(2) storage in a CO_(2)‐EGS are both dependent on the in situ flow pathway network created by induced fluid injection.These thermo‐mechanical interactions can be complex and induce varying alterations in the mechanical response when the working fluid is water (in EGS) or supercritical CO_(2)(in CO_(2)‐EGS),which could impact the geothermal energy recovery from geological formations.Therefore,there is a need for a deeper understanding of the heat extraction process in EGS and CO_(2)‐EGS.This study presents a systematic review of the effects of changes in mechanical properties and behavior of deep underground rocks on the induced flow pathway and heat recovery in EGS reservoirs with or without CO_(2) storage in CO_(2) ‐EGS.Further,we proposed waterless‐stimulated EGS as an alternative approach to improve heat energy extraction in EGS.Lastly,based on the results of our literature review and proposed ideas,we recommend promising areas of investigation that may provide more insights into understanding geothermo‐mechanics to further stimulate new research studies and accelerate the development of geothermal energy as a viable clean energy technology.

Development and Evaluation of Intersection-Based Turning Movement Counts Framework Using Two Channel LiDAR Sensors

This paper presents vehicle localization and tracking methodology to utilize two-channel LiDAR data for turning movement counts. The proposed methodology uniquely integrates a K-means clustering technique, an inverse sensor model, and a Kalman filter to obtain the final trajectories of an individual vehicle. The objective of applying K-means clustering is to robustly differentiate LiDAR data generated by pedestrians and multiple vehicles to identify their presence in the LiDAR’s field of view (FOV). To localize the detected vehicle, an inverse sensor model was used to calculate the accurate location of the vehicles in the LiDAR’s FOV with a known LiDAR position. A constant velocity model based Kalman filter is defined to utilize the localized vehicle information to construct its trajectory by combining LiDAR data from the consecutive scanning cycles. To test the accuracy of the proposed methodology, the turning movement data was collected from busy intersections located in Newark, NJ. The results show that the proposed method can effectively develop the trajectories of the turning vehicles at the intersections and has an average accuracy of 83.8%. Obtained R-squared value for localizing the vehicles ranges from 0.87 to 0.89. To measure the accuracy of the proposed method, it is compared with previously developed methods that focused on the application of multiple-channel LiDARs. The comparison shows that the proposed methodology utilizes two-channel LiDAR data effectively which has a low resolution of data cluster and can achieve acceptable accuracy compared to multiple-channel LiDARs and therefore can be used as a cost-effective measure for large-scale data collection of smart cities.

Optimizing bus services with variable directional and temporal demand using genetic algorithm

As a major mode choice of commuters for daily travel, bus transit plays an important role in many urban and metropolitan areas. This work proposes a mathematical model to optimize bus service by minimizing total cost and considering a temporally and directionally variable demand. An integrated bus service, consisting of all-stop and stop-skipping services is proposed and optimized subject to directional frequency conservation, capacity and operable fleet size constraints. Since the research problem is a combinatorial optimization problem, a genetic algorithm is developed to search for the optimal result in a large solution space. The model was successfully implemented on a bus transit route in the City of Chengdu, China, and the optimal solution was proved to be better than the original operation in terms of total cost. The sensitivity of model parameters to some key attributes/variables is analyzed and discussed to explore further the potential of accruing additional benefits or avoiding some of the drawbacks of stop-skipping services.

Assessment of nano-to-micro-scale geomechanical properties and their time-dependent behavior: Current status and progressive perspectives

Rocks can deform at varying scales(nano-,micro-and macro-scale)under different temperatures,pressures,stresses,and time conditions.Sub-core scale(nano-to micro-scale)changes in rock properties can influence local(fine-scale)and bulk scale(macro-scale)rock deformation.However,there is a lack of comprehensive knowledge on how rock deformation at sub-core scale(i.e.,nano-to micro-scale)is assessed and its potential to accurately predicte and estimate the macro-scale mechanical behavior of rocks.This study presents a comprehensive and forward-leaning review of the assessment of nano-scale and micro-scale rock mechanical parameters,their timedependent behavior,and potential applications in rock engineering.Also,we highlighted the key findings based on experimental and numerical methods for evaluating rock mechanical parameters,and presented the limitations of these approaches.Further,we discussed the reliability of sub-core scale mechanical assessments in predicting macromechanical(larger-scale)properties and the behavior of rocks in geo-engineering.Finally,we offer recommendations to advance investigations focused on rock mechanical assessments at these smaller scales and provide a more accurate characterization at the sub-core scale.

Analyzing thermal maturity effect on shale organic matter via PeakForce quantitative nanomechanical mapping

Organic-rich shales have gained significant attention in recent years due to their pivotal role in unconventional hydrocarbon production.These shale rocks undergo thermal maturation processes that alter their mechanical properties,making their study essential for subsurface operations.However,characterizing the mechanical properties of organic-rich shale is often challenging due to its multiscale nature and complex composition.This work aims to bridge that knowledge gap to fully understand the nanomechanical properties of Shale organic matter at various thermal maturation stages.This study employs PeakForce Quantitative Nanomechanical Map-ping(PF-QNM)using Atomic Force Microscopy(AFM)to investigate how changes at the immature,early mature,and peak mature stages impact the mechanical properties of the Bakken Shale organic matter.PF-QNM provides reliable mechanical measurements,allowing for the quantification and qualification of shale constituents'elastic modulus(E).We also accounted for the effect of probe type and further analyzed the impact of probe wear on the nanomechanical properties of shale organic matter.In immature shale,the average elastic modulus of organic matter is approximately 6 GPa,whereas in early mature and peak mature shale,it decreases to 5.5 GPa and 3.8 GPa,respectively.Results reveal a mechanical degradation with increasing thermal maturation,as evidenced by a reduction in Young's modulus(E).Specifically,the immature shale exhibits an 8%reduction in E,while the early mature and peak mature shales experience more substantial reductions of 31%and 37%,respectively.This phenomenon could be attributed to the surface probing of low-modulus materials like bitumen generated during heating.The findings underscore the potential of AFM PF-QNM for assessing the nanomechanical characteristics of complex and heterogeneous rocks like shales.However,it also highlights the need for standardized mea-surement practices,considering the diverse components in these rocks and their different elastic moduli.

Assessment of inherent heterogeneity effect on continuous mechanical properties of shale via uniaxial compression and scratch test methods

Shale reservoirs have been a significant focus of hydrocarbon production over the past few decades,and the mechanical assessment of target shale reservoirs has been critical to successful field operations,especially in hydraulic fracturing and well completions.The Unconfined compressive strength(UCS)and Poisson's ratio(ν)are critical mechanical properties in shale reservoir assessment.The estimation and measurement of shale mechanical properties are often erroneous by not accounting for their heterogeneous and pre-existing features,which yield variability of shale mechanical properties along their lithostratigraphy.Thus,there is a need to investigate the degree of correlation and accuracy in multiscale mechanical evaluations of heterogeneous shales,and the correlation between such micromechanical and macromechanical measurements.This study investigated the impact of inherent heterogeneity on the measurement of continuous micromechanical and macromechanical properties of shale reservoirs using scratch test(ST)and uniaxial compression test(UCT)methods,and the degree of correlation(correlation coefficient,r)of measurements in shale was further assessed for the variability of their measured properties.Shale core samples from three distinct shale formations were utilized and studied,and the core samples were subjected to ST and UCT,respectively.The results from this study showed that despite inherent heterogeneous anomalies and natural fractures in the shale samples analyzed,there is a good degree of correlation(UCS:r=0.73;ν:r=0.89)in the micro-and macro-mechanical properties of shales using two independent experimental tests(ST and UCT).This study provides insights for improving the accuracy of mechanical evaluations and numerical modeling in shales with a high degree of heterogeneity and pre-existing natural fractures.The results indicate that when considering the structural complexity and heterogeneity of unconventional reservoirs such as shales,the ST method can provide a better continuous micromechanical assessment of shales.In contrast,the UCT can provide a better bulk macromechanical measurement of shales.

Coupled tripartite investigation of breaker fluid invasion and impact on hydrocarbon recovery in sandstone reservoirs

Breaker fluids are designed to dissolve filter cakes by breaking their long-chain molecules,thereby removing solid deposits on the wellbore wall.Although breaker fluids are not intended to infiltrate the hydrocarbon reservoir,they can invade and cause formation damage by altering sandstone reservoirs'wettability and relative permeability.This can lead to a reduction in the overall reservoir performance.This study coupled tripartite methods to investigate the potential impact of breaker invasion and transport in hydrocarbon reservoirs and its multiscale effect on the performances of sandstone reservoirs.We utilized experimental,analytical,and numerical methods to assess and predict the susceptibility of reservoirs to breaker fluid invasion and transportation.Our experimental and empirical investigations considered varying breaker fluid formulations to evaluate the effects of breaker fluid concentration,formation temperature,and solution gas-oil ratio(GOR)on residual-oil saturation(ROS)and oil-water relative permeability.By adopting the ROS and relative permeability associated with the 50%v/v breaker fluid mixture,the performance of the hydrocarbon reservoir was numerically simulated under the limiting scenarios of no-invasion,moderate-invasion,and deep-invasion of breaker fluid.The results indicate a positive correlation between breaker fluid concentration and ROS,highlighting the risks that breaker fluid invasion and deep infiltration pose to hydrocarbon recovery.Further,results show that both live-oil condition(LOC)and dead-oil condition(DOC)reservoirs are susceptible to the detrimental impacts of breaker fluid infiltration,while their invasion can reduce hydrocarbon recovery in both LOC(-6%)and DOC(-28%).The multi-scale effects on reservoir performance are more pronounced at near-wellbore and DOC than at far-field and LOC.Findings from this work provide valuable insights into the complexity of breaker-fluid invasion in sandstone reservoirs and the mitigation of associated risks to reservoir performance.

Physiological Changes and Antioxidative Mechanisms of Alternanthera philoxeroides in Phytoremediation of Cadmium

This study evaluated the physiological characteristics(e.g.,growth parameters,chlorophyll content,metabolites and antioxidative enzymes activity)of Alternanthera philoxeroides(A.philoxeroides),as a hyperaccumulator plant,during the phytoremediation of cadmium(Cd)from water.After cultivating A.philoxeroides in a Cd-containing medium for 30 days,the growth rate was inhibited by up to 33.5%as the exposed Cd concentration increased to 0.80 mmol·L−1.Cd exposure interfered with the photosynthesis of A.philoxeroides and caused oxidative stress as indicated by the rise of malondialdehyde(MDA)and H2O2,which increased by 8 times and 3 times compared to the control group.Moreover,high exposure concentrations of Cd also reduced the activities of multiple antioxidants(e.g.,GSH and AsA),indicating the inhibition of Cd on the plant’s ability to mitigate oxidative damage.Finally,the fluorescent patterns of the rhizosphere dissolved organic matter(rDOM)revealed three major components(humic,fulvic substances and protein-like substances)well correlated with the changes in antioxidant activities.Partial least-squares discriminant analysis(PLS-DA)visualized the difference in the activity of the antioxidative enzymes between different groups.The study unravelled deep insights into the potential mechanisms of tolerance and resistance of A.philoxeroides for phytoremediation of Cd pollution.

Magnetotactic bacteria:Characteristics and environmental applications

Magnetotactic bacteria(MTB)are a group of Gram-negative prokaryotes that respond to the geomagnetic field.This unique property is attributed to the intracellular magnetosomes,which contains membrane-bound nanocrystals of magnetic iron minerals.This review summarizes the most recent advances in MTB,magnetosomes,and their potential applications especially the environmental pollutant control or remediation.The morphologic and phylogenetic diversity of MTB were first introduced,followed by a critical review of isolation and cultivation methods.Researchers have devoted to optimize the factors,such as oxygen,carbon source,nitrogen source,nutrient broth,iron source,and mineral elements for the growth of MTB.Besides the applications of MTB in modem biological and medical fields,little attention was made on the environmental applications of MTB for wastewater treatment,which has been summarized in this review.For example,applications of MTB as adsorbents have resulted in a novel magnetic separation technology for removal of heavy metals or organic pollutants in wastewater.In addition,we summarized the current advance on pathogen removal and detection of endocrine disruptor which can inspire new insights toward sustainable engineering and practices.Finally,the new perspectives and possible directions for future studies are recommended,such as isolation of MTB.genetic modification of MTB for mass production and new environmental applications.The ultimate objective of this review is to promote the applications of MTB and magnetosomes in the environmental fields.

Experimental and computational assessment of 1,4-Dioxane degradation in a photo-Fenton reactive ceramic membrane filtration process

The present study evaluated a photo-Fenton reactive membrane that achieved enhanced 1,4-Dioxane removal performance.As a common organic solvent and stabilizer,1,4-Dioxane is widely used in a variety of industrial products and poses negative environmental and health impacts.The membrane was prepared by covalently coating photocatalyst of goethite(α-FeOOH)on a ceramic porous membrane as we reported previously.The effects of UV irradiation,H_(2)O_(2)and catalyst on the removal efficiency of 1,4-Dioxane in batch reactors were first evaluated for optimized reaction conditions,followed by a systematical investigation of 1,4-Dioxane removal in the photo-Fenton membrane filtration mode.Under optimized conditions,the 1,4-Dioxane removal rate reached up to 16%with combination of 2 mmol/L H_(2)O_(2)and UV365 irradiation(2000µW/cm^(2))when the feed water was filtered by the photo-Fenton reactive membrane at a hydraulic retention time of 6 min.The removal efficiency and apparent quantum yield(AQY)were both enhanced in the filtration compared to the batch mode of the same photo-Fenton reaction.Moreover,the proposed degradation pathways were analyzed by density functional theory(DFT)calculations,which provided a new insight into the degradation mechanisms of 1,4-Dioxane in photo-Fenton reactions on the functionalized ceramic membrane.

Concurrent adsorption and reduction of chromium(Ⅵ)to chromium(Ⅲ)using nitrogen-doped porous carbon adsorbent derived from loofah sponge

To develop highly effective adsorbents for chromium removal,a nitrogen-doped biomass-derived carbon(NHPC)was synthesized via direct carbonation of loofah sponge followed by alkali activation and doping modification.NHPC possessed a hierarchical micro-/mesoporous lamellar structure with nitrogen-containing functional groups(1.33 at%),specific surface area(1792.47 m2/g),and pore volume(1.18 cm^(3)/g).NHPC exhibited a higher Cr(Ⅵ)adsorption affinity than the HPC(without nitrogen doping)or the pristine loofah sponge carbon(LSC)did.The influence of process parameters,including pH,dosage,time,temperature,and Cr(Ⅵ)concentration,on Cr(Ⅵ)adsorption by NHPC were evaluated.The Cr(Ⅵ)adsorption kinetics matched with the pseudo-second-order model(R^(2)≥0.9983).The Cr(Ⅵ)adsorption isotherm was fitted with the Langmuir isotherm model,which indicated the maximum Cr(Ⅵ)adsorption capacities:227.27,238.10,and 285.71 mg/g at 298K,308K,and 318K,respectively.The model analysis also indicated that adsorption of Cr(Ⅵ)on NHPC was a spontaneous,endothermal,and entropy-increasing process.The Cr(Ⅵ)adsorption process potentially involved mixed reductive and adsorbed mechanism.Furthermore,computational chemistry calculations revealed that the adsorption energy between NHPC and Cr(VI)(-0.84 eV)was lower than that of HPC(-0.51 eV),suggesting that nitrogen doping could greatly enhance the interaction between NHPC and Cr(VI).

Challenges in characterization of nanoplastics in the environment

Plastic pollution has been a legacy environment problems and more recently,the plastic particles,especially those ultrafine or small plastics particles,are widely recognized with increasing environmental and ecological impacts.Among small plastics,microplastics are intensively studied,whereas the physicochemical properties,environmental abundance,chemical states,bioavailability and toxicity toward organisms of nanoplastics are inadequately investigated.There are substantial difficulties in separation,visualization and chemical identification of nanoplastics due to their small sizes,relatively low concentrations and interferences from coexisting substances(e.g.,dyes or natural organic matters).Moreover,detection of polymers at nanoscale is largely hampered by the detection limit or sensitivity for existing spectral techniques such as Transformed Infrared Spectroscopy(FTIR)or Raman Spectroscopy.This article critically examined the current state of art techniques that are exclusively reported for nanoplastic characterization in environmental samples.Based on their operation principles,potential applications and limitations of these analytical techniques are carefully analyzed.