Hasil untuk "Engineering geology. Rock mechanics. Soil mechanics. Underground construction"

Shan Li, Peng Lin, Kai Yang et al.

Hyperspectral imaging provides a novel approach for intelligent geological perception in tunnelling and underground engineering due to its high spectral resolution, nondestructive nature, and combined spectral-spatial information. However, in confined underground spaces, noise is often introduced by short exposure times, low illumination, and dust, and limited spatial resolution can cause mixed pixel effects, complicating data processing. This study presents an underground hyperspectral imaging-based mineral mapping method that achieves wall-rock visualization and semi-quantitative mineral mapping through image denoising and spectral unmixing. A spatial-spectral recurrent transformer U-Net is developed to reduce noise by leveraging spectral band correlations and nonlocal spatial-texture dependencies. A Dirichlet-based mixed pixel simulation is used to address spectral mixing, with the N-FINDR algorithm identifying endmember minerals, and the fully constrained least squares method to estimate mineral abundances. When applied to a water diversion tunnel in Shanxi, the method generates spatial distribution maps of dolomite and calcite. The experimental results confirm its effectiveness for intelligent geological logging and subsurface geological feature analysis.

Changdong Ding, Shaoming Ouyang, Lide Zhang et al.

Qihang Li, Yunmin Wang, Jiawen Wang et al.

Underground mining in mountainous regions presents a significant geological hazard, characterised by the occurrence of land subsidence and movement of overlying strata. To aggrandise the theory of mine rock mechanics, we conducted a systematic investigation into the deformation and failure mechanisms of overlying strata as well as the patterns of surface subsidence in mountainous regions. With the method of engineering mechanics and theoretical analysis, supplemented by the universal distinct element code (UDEC) numerical simulation, the mining status of Songzao mine was simulated effectively. Herein, the results revealed that the nonlinearity of the overlying strata failure field occurred during mining, as evidenced by an increase in the failure field when the coal approached the seam roof. The subsidence curve of the underlying lower strata exhibits an inverted trapezoid pattern, while that of the overlying upper overburden displays a funnel‐shaped trend. Additionally, the upward transmission displacement velocity was significantly attenuated due to the shielding effect exerted by the key stratum in the overburden, resulting in a greater spatial separation from the underlying strata. The critical stratum fractures as the working face advanced to 120 m, subsequently leading to an increase in vertical displacement and cessation of surface subsidence. The surface subsidence value and speed, however, exhibited a gradual increase as the coal seam mining progressed. Due to the influence of mountain surface landforms, the subsidence value of convex landforms surpasses that of concave landforms, thereby expediting the rate of subsidence and resulting in geological hazards.

Bingbing Yu, Guohao Wang, Weixian Cheng et al.

PurposeThis paper attempts to combine the application of artificial intelligence in predicting and evaluating the classification of surrounding rock grades and provides guidance for subsequent support design and reinforcement support operations.Design/methodology/approachThis paper discusses the use of BPNN as the primary tool, combined with three swarm bionic optimization algorithms (GA, PSO, GWO), to solve stability evaluation and grade prediction of surrounding rock in ultra-deep roadway excavation.FindingsTaking the Great Wall ore group as the core and the Shanghaimiao mining area as the extension, the optimal model is applied to the classification of surrounding rock grade in ultra-deep roadway engineering. Prediction results show that the performance of BPNN models is excellent.Research limitations/implicationsDue to the limitations of geological conditions and construction environment in deep coal mines, the period of roadway excavation is too long, resulting in less data collection.Practical implicationsThe prediction results can provide guidance for the excavation method, support scheme correction and reinforcement support scheme design of deep coal mine roadway engineering.Social implicationsIt provides guidance for deep mining of coal mine (the premise of surrounding rock support stability), so as to ensure the economic and safety benefits of coal enterprises.Originality/valueThe neural network is applied to rock mechanics in a deep site for the first time, which is used to solve the prediction direction of surrounding rock grade evaluation. The index of the input layer is determined by combining the “three high and one disturbance” with the on-site construction situation, which is closer to the actual project. The swarm intelligent bionic algorithms are selected to optimize the hyperparameters of back propagation neural network, so as to improve the accuracy of the models. The classification and evaluation system of surrounding rock for the Great Wall ore group is constructed, which is the core of Shanghaimiao mining area in the northwest of China, guiding the dynamic adjustment of on-site excavation and support operations.

A. Bilal, M. Jebur, Askar Zhussupbekov et al.

I. Ofrikhter, A. B. Ponomarev

Tianmeng Lei, Yefei Wang, Mingchen Ding et al.

To solve the problem whereby an oil reservoir with applicable boundaries of the current sand-inhibiting and water-control agent is unclear, a supramolecular sand-inhibiting and water-control agent PDKM was prepared using acrylamide (AM), methacryloxyethyltrimethyl ammonium chloride (DMC), styrene (SM), and γ-methacryloyloxypropyltrimethoxysilane (KH570) as comonomers. The molecular structure of PDKM was verified by 1H-NMR and FT-IR. On the basis of establishing an evaluation method that can screen the performance of sand-inhibiting agent at a flow rate of 100 mL/min, the oil reservoir applicable boundaries of PDKM were obtained through the evaluation of sand-inhibiting and water-control performance. The experimental results show that when the concentration of PDKM is 5000 mg/L, the oil reservoir conditions are temperature ≤90 °C, formation water salinity ≤21,249 mg/L, the degree of sand production corresponding to slight sand production and particle migration, crude oil viscosity ≤50 mPa·s, primary water flooding water cut ≥75%, and formation permeability contrast ≤2. The performance with respect to sand inhibiting and water control can all reach an excellent level. Therefore, the PDKM solves the problem whereby the applicability of the current sand-inhibiting and water-control agent is unclear, and provides direction for the selection of suitable products in the oilfield production site.

Majcher Krzysztof

This paper presents theoretical considerations relating to the possibility of fully identifying the parameters of a numerical model describing a building structure. An input–output method with system momentum change is proposed for this purpose, thanks to which the basic matrices describing the system were identified, that is, the mass matrix M, the damping matrix C and the stiffness matrix K. The proposed way of system identification is based on the knowledge of the vibration excitation (the input signal) and the structure’s dynamic response (the output signal) to the applied excitation, and the analyses are performed in the time domain. The reverse problem defined in this way consists of determining the coefficients of matrices M, C and K at any discrete point of time. In the case when the vibrations of the system are excited by kinematic excitation (ground motion), in order for the inverse problem to be solvable, either knowledge of the mass matrix or a known modification of the system masses is required. This is due to the representation of excitation forces, which in the case of kinematic excitation contains a mass matrix in their full description. This paper presents a method based on an inertial modification, that is, adding known masses to the analysed system, which entails a change in system momentum. The addition of known masses to the system being identified results in the introduction of additional known forces into the system. In this way, a heterogenous linear algebraic system of equations is obtained in the reverse problem and the coefficients of the particular matrices M, C and K are calculated from this system of equations. Moreover, considering the fact that the input signal and the output signal are known in many time points, the proposed procedure leads to a set of systems of equations.

Ankit Garg, Zhiwen Wu, Can Liu et al.

ZHANG Yu 1, ZHANG Qing 1, WANG Yijie 2, CAI Guojun 3, DONG Xiaoqiang 4, DU Yanjun 1, JIANG Ningjun 1

With the acceleration of urbanization, the remediation, development and reuse of heavy metal-contaminated sites have attracted increasing attention. Taking the typical heavy metal contaminant lead as the research object, the effects of lead concentration on the bacterial activity indexes such as pH of soil, number of viable cell, concentration of urea and ammonium are investigated by using the biostimulated MICP method. The unconfined compressive strength, permeability and toxicity leaching concentration of the solidified lead-contaminated soil are used to evaluate the solidification effects. The findings demonstrate that the biostimulation method can realize the enrichment of ureolytic bacteria in low lead concentration contaminated soils. The number of viable cell can reach 109 CFU/g after 7 days of enrichment, but the high concentration of lead contaminants significantly inhibits the growth and activity of microorganisms. The strength and impermeability show an increasing trend with solidifying time, and the strength of 40 mM lead-contaminated soil increases significantly and the permeability coefficient can be decreased to 6.5×10-6 m/s after solidifying for 14 days. The leaching concentration also decreases with solidifying time, and the leaching concentration of the low lead concentration-contaminated soil solidified for 14 days can be lower than 0.1 mg/L in neutral or weakly acidic environment. Based on the engineering properties and environmental safety tests, the solidification mechanism of the lead-contaminated soil treated by the biostimulated MICP is revealed by combining the scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and microbial 16 s whole genome resequencing.

GUO Chaofeng 1, CHENG Wen-Chieh 1, 2, HU Wenle 1, KANG Nongbo 1

The rapid development in the western areas of China has resulted in a growing problem of heavy metal pollution in the loess land. The electrokinetic remediation has gained attention due to its great maneuverability. However, certain factors such as polarization phenomena and precipitation of heavy metals near the cathode have lead to a decrease in the efficiency of the electrokinetic remediation. Therefore, focusing on studying the copper and lead-contaminated loess as the research subject, by combining the technology of chelating agent coupling electric remediation with the addition of catholyte, the effects of tartaric acid, citric acid and EDTA as the cathode electrode liquid on the removal efficiency of copper and lead metals in loess as well as the removal mechanism are investigated. The results indicate that the tartaric acid, citric acid and EDTA can enhance the migration capability of copper and lead through complexation, thereby improving the removal efficiency of these metals to varying estents. The improvement in the removal efficiency of copper and lead metals is particularly noticeable in the vicinity of the cathode. Among the three chelating agents, the EDTA exhibits strong chelating capability and can react with copper and lead metals across different pH ranges, resulting in the formation of a more stable complex and enhancing the removal efficiency. Compared with the control group, the EDTA forms a stable complex by coordinating with heavy metals through six atoms, converting them into exchangeable states with enhanced migration capabilities, and making them easier to remove. As a result, the overall removal efficiencies of copper and lead increase to 55.4% and 27.2%, respectively.

Yong-jun Su, Hui Tang, Ai-min Wu et al.

Natural and geological environmental conditions have an important impact on the planning and construction of sponge cities. This paper analyzes geological factors that influence the usage of natural sponge bodies, taking the Shuanghe lake district of Zhengzhou airport zone as an example. An evaluation system with seven factors has been established and the weights of these factors are determined using the analytic hierarchy process (AHP) method. Overlay analysis is then carried out on all factors using GIS to evaluate the geological suitability of the construction of the sponge city. The results show that geologically suitable area for city construction in Shuanghe lake district accounts for 12.3%, relatively suitable area accounts for 76.1%, and relatively unsuitable area accounts for 11.6%. For suitable and relatively suitable areas, we should make full use of the advantages of surface infiltration, vadose zone transportation and aquifer storage to build a sponge city infrastructure with geological engineering as the main component, supplemented by engineering measures such as surface water storage and drainage, and jointly establish a sustainable urban hydrological cycle. For less suitable areas, artificial rain and flood control works, such as roof garden, should be considered. The findings of this paper can serve as an important reference for sponge city planning and construction not only in the research area but also in other regions with similar geological conditions.

Xueming Yang, W. Daniel Reynolds, Craig F. Drury et al.

Summer-seeding legume cover crops can reduce erosion, mitigate nitrate leaching losses during the non-growing season, and provide bio-accumulated nitrogen (N) to the following crop. Very little information is available, however, on the most effective methods for terminating summer-seeded cover crops, or on the amount of N they can provide to subsequent crops. We therefore evaluated the impacts of selected legume cover crops and cover crop termination-tillage methods on corn (Zea mays L.) N credit and grain yield in a soybean (Glycine max Merr.) - winter wheat (Triticum aestivum L.)/cover crop - corn rotation over 3 consecutive years on a clay loam soil in southwestern Ontario. The cover crops were summer-seeded after wheat harvest, and included hairy vetch (Vicia villosa L. Roth), red clover (Trifolium pratense L.), white clover plus crimson clover mix (incarnatum and Trifolium alba L.), and a no cover crop control (CK). The cover crops were nested within termination-tillage method, including moldboard plow-down in fall, and herbicide spray-down in spring under strip-tillage or no-tillage then corn planting. Nitrogen fertilizer to corn was applied via side-dress at 200 kg N ha-1 to the CKs, and at 100 kg N ha-1 to the cover crops. Averaged over 3 years, above-ground biomass N level followed the pattern: hairy vetch > white clover plus crimson clover mix > red clover for fall plow-down termination. There were no significant differences in cover crop biomass N levels for spring termination. Corn response to cover crop was significantly affected by termination-tillage method and cover crop species, with poor corn stands after no-tillage, red clover and white plus crimson clover. Fall plow-down termination provided a range in N credit of 80-85 kg N ha-1, which was significantly greater than the N credit under herbicide spray-down in spring. Under spring strip-tillage and no-tillage, hairy vetch produced significantly greater corn grain yields than red clover and white plus crimson clover mix.

Meng Xiao, Jie Cui, Ya-dong Li et al.

Site condition is an important part of urban underground space development and construction. The seismic fortification of the site plays an important role in the safety of the whole project. To study the seismic dynamic response of the site under different geological conditions, seismic waves of different intensities (Chichi wave and Kobe wave) were input to a rock site with good geological conditions and a soft soil site, respectively. In this paper, the dynamic responses of these two types of free sites were calculated and analyzed using DEEPSOIL numerical simulation software. The dynamic responses of different types of sites under strong shock and persistent earthquakes are discussed under the equivalent linear and nonlinear conditions, and the related dynamic parameters are studied. The results show that the equivalent linear method is more effective than the nonlinear method, especially in the calculation of the strong nonlinear soft soil response induced by strong earthquakes. The amplification effect is more obvious in rock layer sites under strong earthquakes, and the “weakening” effect of soft soil sites is more obvious. Arias’s strength values show that both types of sites are safe under the incident of the two waves, but soft soil sites have better seismic performance. The results calculated by the equivalent linear method are larger and more unsafe; in particular, in the case of a strong earthquake with a stronger nonlinear Kobe wave, the results are more inaccurate. The purpose of this study is to provide a reference for seismic design and reinforcement measures of underground engineering.

Zhigang Li, Jiahao Wang, Jinyuan Yang et al.

In view of the characteristics of the Mesozoic oil reservoirs in the southern Ordos block such as large buried depth, strong heterogeneity, unclear understanding of oil and gas distribution, and immature prediction technology for engineering construction mechanism and effects, the fracture propagation morphology is studied. The 3D geomechanical parameters are truly 3D distributed by the integrated fracturing simulation technology of geological engineering and the research results of reservoir evaluation and rock mechanics. The spatial distribution of rock mechanics parameters of tight sandstone reservoir and interlayer is accurate. Considering the heterogeneity between layers, the distribution law of true 3D fractures in the real formation environment of high temperature and high pressure is simulated. The simulation results show that the fractures simulated by the 3d geomechanical model updated in real time are irregular and asymmetrical, and have a high degree of matching with the seismic data. This fracture model can guide the field construction and optimize the fracturing parameters of subsequent Wells to ensure that fractures occur in the most favorable position, which has high practical value and economic benefits.

Yingming Feng, Yingming Feng, Xingyun Chen et al.

Root border cells (RBCs) are a group of cells that originated from the root cap meristem, which are developed by genetic regulation and play a variety of biological functions. Being composed of a homologous single cell population with high metabolic activity and intact cell walls, RBCs represent a highly useful tool for studying various aspects of plant mineral absorption and utilization, as well as plant-soil-microbiome interactions in the rhizosphere. Research on RBCs also promise to become a hotspot in the context of understanding root adaptive responses to hostile environments. In order to take advantage of RBCs as an ideal single cell system in plant-environmental interactions, we summarized the production and function of RBCs and built-up the methodology for RBCs culturing, purification, and quantity control for plant research. The latter is done by using a case study of the application of RBCs to study mechanisms of Al toxicity in plants. This work offers plant scientists a new cognition of adopting RBCs as a convenient single cell system for the multidisciplinary research including (but not limited to) plant physiology, development and genetics, nutrition, and stress and adaptation. Root border cells (RBCs) are derived from the root cap and represent a population of living cells with special physiological activity and biological roles that are different from the root cap cells per se. After being separated from the root cap, RBCs become more active in metabolism than the progenitor root cap cells; for example, they incorporate labeled amino acids into protein 2.6-fold more efficiently than the cells of the root cap. In addition, mRNA and protein were differentially expressed between root cap cells and RBCs. Since the production of RBCs is genetically regulated and RBCs played a variety of biological functions in resistance to biotic and abiotic stresses occurred in the rhizosphere, RBCs were suggested as an ideal single cell system for the study the response of plant root cells to nutrient availability, environmental stresses, and in plant-microbial interactions. Some studies revealed that RBCs, which development is regulated by endogenous and exogenous signals, are biologically viable in the majority of higher plant species. This work reviews the research on RBCs in plant environment interaction and describes the case study of RBCs as a convenient single cell system to study plant responses to Al toxicity.

Jiyao Tu, Jianqing Ji, Dalai Zhong et al.

To reveal the tectonic evolution process of the eastern Himalayan syntaxis and provide basic geological data for probable significant engineering construction, this study reports 9 biotite 40Ar/39Ar ages in the middle reach of the Purlung Tsangpo River and semiquantitatively calculates the rock erosion rates represented by these ages using the modeling code "Pecube". The measured biotite 40Ar/39Ar ages range from 103-12.5 Ma, corresponding to erosion rates ranging from 0.068-0.5 km/Ma. The rock erosion rates of the Purlung Tsangpo River have obvious differences between the western and eastern sections, which are characterized by the downstream section (western section) being significantly higher than that of the middle section (eastern section). Ages and simulation results show that in contrast to the eastern Himalayan syntaxis, the crust erosion rate in the middle reach of the Purlung Tsangpo River is lower and stable. The Purlung Tsangpo River was captured by the Yarlung Tsangpo River, which allowed the Purlung Tsangpo River downstream (western section) to change into a youth stage of fluvial geomorphological evolution again.The rapid river incised likely resulted in the erosion rate differences between the western and eastern sections.

الهه احمدپور دهکردی, علی عباسی سورکی, مهدی پژوهش et al.

سابقه و هدف: فرسایش بادی یکی از مشکلات جدی در مناطق خشک و نیمه خشک محسوب می‌شود. جهت کنترل فرسایش بادی لازم است اقداماتی در سطح خاک متمرکز گردد. روش موانع شطرنجی کلش به عنوان یک فناوری ارزان، مؤثر و آسان، نقش مهمی در به دام انداختن گرد و غبار داشته و فرسایش بادی را کاهش می‌دهد. بنابراین هدف از این پژوهش بررسی تأثیر روش موانع شطرنجی کلش بر خصوصیات فیزیکی و شیمیایی خاک و کاهش احتمالی گرد و غبار در اراضی در معرض فرسایش بادی دشت مرغ شهرکرد می‌باشد. مواد و روش‌ها: موانع شطرنجی کلش در دی ماه سال 1396 در بخشی از دشت مرغ در جنوب شهر شهرکرد مرکز استان چهارمحال و بختیاری، به صورت الگوی مربعی 1×1 متر کار گذاشته شدند. کلش ها به صورت عمودی در عمق 15 سانتی‌متر در خاک مدفون و ارتفاعی حدود 20 سانتی‌متر در بالای خاک ایجاد نمودند. این مطالعه در قطعه زمینی به طول 20 متر و عرض 25 متر اجرا شد. مساحتی مشابه از خاک دست نخورده نیز به عنوان شاهد در نظر گرفته شد. به منظور بررسی میزان فرسایش بادی و کنترل آن، تله‌های رسوب‌گیر عمودی با سطح مقطع دایره‌ای از جنس لوله پی وی سی به صورت تصادفی و به تعداد 5 عدد در زمین شاهد، 5 عدد در محدوده اول موانع شطرنجی، 5 عدد در وسط و 5 عدد در آخر زمین در جهت باد غالب کار گذاشته شدند. نمونه‌برداری رسوبات از اواخر تیر ماه آغاز و هر 30 روز یک بار در پنج مرحله صورت گرفت. ارتفاع تله‌ به چهار قسمت 12-0، 24-12، 36-24 و 48-36 سانتی‌متر تقسیم شد و رسوبات جمع‌آوری شده با یکدیگر مقایسه گردید. سرعت و جهت باد نیز در ماه های متناظر اندازه‌گیری و گلباد مربوط به هر ماه رسم شد. داده‌ها به صورت فاکتوریل در قالب طرح بلوک کامل تصادفی با 5 تکرار تجزیه شدند. موقعیت قرارگیری به عنوان عامل اول در سه سطح و طبقات رسوب به عنوان عامل دوم در نظر گرفته شدند. طی دو سال متوالی پس از استقرار موانع، خصوصیات خاک شامل پایداری خاکدانه‌ها، درصد سیلت، رس و شن، کربن آلی، نیتروژن کل و فسفر قابل دسترس نیز اندازه‌گیری شد.یافته‌ها: ایجاد موانع شطرنجی در خاک به طور معنی‌داری میزان رسوب را کاهش داد. این روند در پنج ماه نمونه برداری به ویژه در تله-های موجود در آخر موانع مشاهده شد. سرعت باد برخوردی به موانع و انرژی آن کاهش قابل توجهی یافته، لذا میزان رسوبات در آخر موانع کمترین مقدار بود. همچنین میزان رسوبات در هر سه محدوده اول، وسط و آخر موانع شطرنجی در ماه تیر، مرداد، شهریور و مهر با افزایش طبقه ارتفاعی تله روند کاهشی داشت. اما در آبان ماه رسوبات در ارتفاع‌های ابتدایی افزایش یافته که بیانگر سرعت بالا‌تر باد و جا-به‌جایی ذرات جهشی است. میانگین وزنی قطر خاکدانه در کنار موانع شطرنجی افزایش یافت که ممکن است با افزایش معنی‌دار کربن آلی در کنار موانع مرتبط باشد. میزان کربن آلی، نیتروژن کل و فسفر قابل دسترس خاک نیز تحت تأثیر موانع شطرنجی کلش قرار گرفت و در کنار مربعات افزایش یافت. از سویی ذرات ریز خاک مانند سیلت و رس نیز در مربعات شطرنجی افزایش یافت که احتمالاً مربوط به عدم بارگیری یا افزایش نشست این ذرات می‌باشد.نتیجه‌گیری: ایجاد روش موانع شطرنجی مقدار رسوبات بادی را نسبت به زمین شاهد به طور قابل توجهی کاهش داد. از سوی دیگر نشست و تثبیت ذرات در موانع افزایش یافت. همچنین این تکنیک سبب بهبود خصوصیات فیزیکی و شیمیایی و افزایش برخی عناصر غذایی خاک گردید که می‌تواند نوید بخش یک میکروکلیمای بهتر برای رشد و استقرار گیاهان و بازگشت تنوع و پایداری به خاک باشد.

K. Dorokhin, O. Boiko, A. Suharev

Summary The main object of seismic and acoustic research during construction is a rock mass, which is understood as a separate part of the geological environment, located in the sphere of engineering influence. This part of the environment is investigated in order to establish the conditions for the construction work and the subsequent operation of the erected structures. Identification and assessment of the formed weakened zones in the host massif is a necessary stage in predicting subsequent precipitation and deformations of engineering structures located in the zone of influence of construction works. The results of geophysical studies are the basis for the development of measures to eliminate adverse factors and processes in the soil mass, and also serve as an important tool for monitoring the effectiveness of measures already taken.

Weicheng Zhang, Andreas Eckert

A micro-annulus (MA) is defined as a high permeability zone or gap initiating/occurring at the casing-cement and cement-formation interfaces during the wellbore life span. An MA can significantly compromise wellbore integrity by establishing enhanced fluid flow pathways. This study uses a staged finite element approach to simulate wellbore integrity during various loading steps of wellbore operations under downhole conditions. Particular emphasis is placed on the processes of cement poro-elastic property evolution, volume variation, and pore pressure variation as part of the cement hardening step. The resulting state of stress during the life cycle of a typical injection well (i.e. hardening, completion, and injection) is analyzed to assess the onset and evolution of micro-annuli at various interfaces of the composite wellbore system under downhole conditions. The results show that cement shear failure is observed at the casing-cement interface during pressure testing (excessive wellbore pressure); and tensile debonding failure initiates at the cement-formation interface due to cement shrinkage during hardening and injection-related cooling (thermal cycling). Sensitivity analyses considering several parameters show that: (1) the degree of poro-elastic bulk shrinkage has significant implications for both shear and tensile failure initiation – the less the cement shrinks, the less likely the failure initiation is; (2) cement integrity increases with increasing depth; (3) cement pore pressure evolution has significant implications for tensile failure – if cement pore pressure decreases more, higher temperature differences can be sustained before an MA occurs; and (4) cement temperature fluctuations during hardening promote initiation of debonding failure. In summary, the results presented indicate that establishing downhole conditions to quantitatively analyze MA generation is necessary. The results are different compared to laboratory studies without considering/simulating downhole conditions. The knowledge from this study can raise the awareness of predicting and evaluating MA under downhole conditions and can be used to supplement and improve future laboratory experiments.