Chemical Engineering Commons^™

Simulation On Acid Gas Removal From Natural Gas Processing With Membrane And Absorption Process, Ratikorn Sornumpol

Chulalongkorn University Theses and Dissertations (Chula ETD)

The comparison using simulations of CO₂ removal from natural gas via membrane separation and monoethanolamine (MEA) absorption has been studied. The membrane model is applied with the single- and two-stage configurations over feed pressures 3,000–9,000 kPa, temperatures 10–59 °C, CO₂ concentrations 20–70 mol %, membrane areas 2,500–5,500 m², and flows 331,800–580,600 m³/h. At 10 °C feed temperature, CO₂ permeability is enhanced while CH₄ selectivity improves slightly, increasing CO₂ capture efficiency up to 74 % with only minor methane losses, though at the cost of higher refrigeration duty. The 10 °C operation also leads to stronger driving force across the membrane, …

Oxygen Fugacity Of Global Ocean Island Basalts, Lori N. Willhite, Ricardo Arevalo, Philip Piccoli, John C. Lassiter, Devin Rand, Matthew G. Jackson, James M.D. Day, Robert W. Nicklas, Marek Locmelis, Thomas J. Ireland, Igor S. Puchtel

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Mantle plumes contain heterogenous chemical components and sample variable depths of the mantle, enabling glimpses into the compositional structure of Earth's interior. In this study, we evaluated ocean island basalts (OIB) from nine plume locations to provide a global and systematic assessment of the relationship between fO₂ and He-Sr-Nd-Pb-W-Os isotopic compositions. Ocean island basalts from the Pacific (Austral Islands, Hawaii, Mangaia, Samoa, Pitcairn), Atlantic (Azores, Canary Islands, St. Helena), and Indian Oceans (La Réunion) reveal that fO₂ in OIB is heterogeneous both within and among hotspots. Taken together with previous studies, global OIB have elevated and heterogenous fO …

Enhancing Reservoir Modeling And Simulation Through Artificial Intelligence And Machine Learning: A Smart Proxy Modeling Approach, Andrew Timothy Jenkins

Graduate Theses, Dissertations, and Problem Reports (ETD)

The application of numerical reservoir simulation (NRS) has been a common approach within the oil and gas industry for decades, providing a means to model and forecast dynamic subsurface interactions, as a basis for reservoir management and development decisions. These techniques have expanded to application within carbon capture utilization and storage (CCUS) projects as domestic and global policy shift towards reducing carbon emissions while maintaining the energy needs of our modern society. NRS techniques have become a core process for permitting approval in Class VI (large-scale geological sequestration) wells due to the fundamental similarity of these types of subsurface processes. …

Preliminary Remote Identification Of Unstable Zone On Large-Scale Waste Dump At Mae Moh Mine Using Insar Technique, Chitra Buth

Chulalongkorn University Theses and Dissertations (Chula ETD)

Mae Moh Mine is one of the largest lignite mine in Southeast Asia, operated by the Electricity Generating Authority of Thailand (EGAT). It is located in the northern part of Thailand, in Mae Moh district, Lampang province. In March 2018, a significant sliding incidence occurred at a waste dump site with sliding area of 1.56 km2 approximately, highlighting the pressing issue of instability within this large-scale waste dump area. This study aims to address this concern in the future and demonstrate an innovative method for investigating the failure by employing Interferometric Synthetic Aperture Radar (InSAR) technology. The methodology involves the …

Enhancing Pipeline Simulations Through Artificial Intelligence And Machine Learning: A Smart Proxy Modelling Approach, Afeez Shittu

Graduate Theses, Dissertations, and Problem Reports (ETD)

ABSTRACT

Enhancing pipeline simulations is essential for improving operational efficiencies and effectively managing risks in the oil and gas industry. Traditional pipeline simulators, relying heavily on mathematical modeling assumptions, often face limitations due to their high energy and computational demands. This thesis addresses these challenges by introducing an innovative approach that integrates artificial intelligence (AI) and machine learning (ML) through a smart proxy model, offering a more efficient, cost-effective, and flexible alternative to conventional full-physics models used in pipeline simulation software.

The primary aim of this research is to develop and implement a smart proxy model capable of accurately predicting …

Geochemical Assessment Of Mineral Sequestration Of Carbon Dioxide In The Midcontinent Rift, Alsedik Abousif, David J. Wronkiewicz, Abdelmoniem Masoud

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

This Study Examines The Potential Of Midcontinent Rift Rocks To Facilitate Long-Term CO2 Sequestration By Providing The Necessary Ca And Mg For Carbonate Mineralization. Surface Samples Were Collected From The Oronto And Bayfield-Jacobsville Groups Around Lake Superior And Used For Petrography And X-Ray Diffraction To Determine Their Mineral Composition. Also, X-Ray Fluorescence Was Also Used To Assess Their Bulk Chemical Composition. The Samples Were Then Exposed To CO2 And Deionized Water In Teflon-Lined Vessels At 90°C, And The Resulting Leachate Fluids Were Analyzed For The Cation Released During The Testing. SEM Microscopy Was Used To Examine The Samples For Potential …

Prediction Of Surfactant Performance From Surfactant Huff-Puff In Carbonate Reservoirs Using A Data-Driven Approach And Desktop Application Development, Y. Yao, Mingzhen Wei, Y. Cui, M. Ali, J. Leng, Y. Qiu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Surfactants have been widely used to alter the wettability of carbonate rocks from oil-wetness to water-wetness and enhanced oil recovery. One of primary methods implemented in filed applications for enhanced oil recovery is surfactant huff-puff. Currently, a large number of surfactant treatments are conducted in laboratories prior to field applications to optimize the design of surfactant huff-puff, test the performance of surfactants, and minimize failure risk. This process is time-consuming since a treatment could last from several days to more than 300 days. Moreover, a fraction of treatments could not improve oil recovery as reported in the literature. In this …

Pattern Recognition For Wettability Alteration With Surfactants In Carbonate Reservoirs By Using Machine Learning, Y. Yao, Mingzhen Wei, M. Ali, Y. Qiu, Y. Cui, J. Leng

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Surfactants Are Widely Applied Agents to Interact with the Adsorbates on Carbonate Rock Surface, Which Could Alter Wettability from Oil-Wetness to Water-Wetness and Thus Enhance Oil Recovery. Surfactant Huff-Puff is Often Conducted to Achieve Wettability Alteration and Has Been Applied under Various Conditions. Currently, Many Investigations Have Been Reported to Apply Conventional Data Analysis Methods to Analyze Different Sets of Surfactant Huff-Puff Projects. Yet the Application of Machine Learning Algorithms to Reveal the Inherent Patterns is Rarely Reported. in This Study, We Integrate Principal Component Analysis (PCA) with Hierarchical Clustering Algorithm (HCA) to Uncover the Hidden Patterns Embedded in Global …

Improving Insar Accuracy For Slow Deformation And Change Detection With Lidar And Gps, Yusupujiang Aimaiti, Vasit Sagan, Cagri Gul, Jeremy Maurer, Jackson D. Cothren, Carla Klehm, Elizabeth A. Koenig, Nathan Scott

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Interferometric Synthetic Aperture Radar (InSAR) uses two or more SAR images over the same region for mapping ground surface displacements through time. InSAR displacements are relative to a reference point due to the 2π phase ambiguity that from unwrapping, and as a result ground control points (GCPs) are often used to calibrate the displacement model and obtain absolute measurements. Errors in InSAR time-series are typically measured with respect to the reference point, but absolute errors are not currently well constrained. To develop absolute error models for InSAR, we generate Sentinel-1 InSAR time-series for Belleville, Illinois and compare time-series with Global …

Novel Re-Crosslinkable Preformed Particle Gels (Rppg) For Parent- And Infill-Well-Fracture Interactions Mitigation, Xiaojing Ge, Adel Alotibi, Ahmed Al-Hlaichi, Yanbo Liu, Tao Song, Junchen Liu, Baojun Bai, Thomas P. Schuman

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Hydraulic fracturing treatments in unconventional infill (or "child") wells can be significantly affected by depletion from existing parent-well, resulting in asymmetrical fracture growth. These issues may lead to excessive load-water production, proppant deposition, casing deformation in the parent well, and unbalanced stimulation of infill wells. To mitigate these effects, various strategies have been proposed, including the use of far-field diverters in child wells and repressurization of parent wells. Additionally, an increasingly popular strategy involves injecting near-wellbore diverters to temporarily plug entry points into the parent wellbores during frac operations on infill wells. To achieve better application, a novel low-cost, self-degradable, …

Experimental Study: Evaluating The Effect Of Low High Viscosity Friction Reducer Concentrations To Transport Proppant Across Static And Dynamic Models, Ghith Biheri, Abdulmohsin Imqam, Shari Dunn-Norman, Khaled Elmaleh

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Hydraulic fracturing treatments may significantly improve the oil production from wells in unconventional reservoirs by enhancing the fracture conductivities. Fracture conductivity can be improved by efficiently transporting and distributing the proppant through the lengths of the fractures. The main target of this study is to evaluate the viscosity and elasticity of high viscosity friction reducer (HVFR) for the purpose of transport and suspend the proppant at a temperature of 25°C. This study an alyzes the settling of proppant across HVFR using two different concentrations, 0.5 and 1 gallon per thousand of gallon (gpt). The tests were conducted using two static …

A Review Of Dielectric Barrier Discharge Cold Atmospheric Plasma For Surface Sterilization And Decontamination, Kolawole Adesina, Ta Chun Lin, Yue-Wern Huang, Marek Locmelis, Daoru Frank Han

Biological Sciences Faculty Research & Creative Works

Numerous investigations have shown that non-equilibrium discharges at atmospheric pressure, also known as "cold atmospheric plasma" (CAP) are efficient to remove biological contaminants from surfaces of a variety of materials. Recently, CAP has quickly advanced as a technique for microbial cleaning, wound healing, and cancer therapy due to the chemical and biologically active radicals it produces, known collectively as reactive oxygen and nitrogen species (RONS). This article reviews studies pertaining to one of the atmospheric plasma sources known as Dielectric Barrier Discharge (DBD) which has been widely used to treat materials with microbes for sterilization, disinfection, and decontamination purposes. To …

Assessing The Potential Of Uav-Based Multispectral And Thermal Data To Estimate Soil Water Content Using Geophysical Methods, Yunyi Guan, Katherine R. Grote

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Knowledge of the soil water content (SWC) is important for many aspects of agriculture and must be monitored to maximize crop yield, efficiently use limited supplies of irrigation water, and ensure optimal nutrient management with minimal environmental impact. Single-location sensors are often used to monitor SWC, but a limited number of point measurements is insufficient to measure SWC across most fields since SWC is typically very heterogeneous. To overcome this difficulty, several researchers have used data acquired from unmanned aerial vehicles (UAVs) to predict the SWC by using machine learning on a limited number of point measurements acquired across a …

Mantle Flow And Olivine Fabric Transition In The Myanmar Continental Subduction Zone, Enbo Fan, Yinshuang Ai, Stephen S. Gao, Yumei He, Kelly H. Liu, Mingming Jiang, Guangbing Hou, Shun Yang, Chit Thet Mon, Myo Thant, Kyaing Sein

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

One of the Major Advances in Mineral Physics and Seismology is the Realization that Different Olivine Fabric Types Are Functions of Temperature, Shear Stress, and Water Content in Oceanic Subducting Systems. the Distribution of Different Olivine Fabric Types and Geodynamic Processes in the Mantle Wedge above a Subducting Continental Slab Remain Poorly Understood. Here, based on Splitting Analysis of Shear Waves Recorded by 46 Stations Recently Deployed in Central Myanmar, We Reveal Trench-Perpendicular Fast Orientations between the 80 and 100 Km Slab Contours Sandwiched between Trench-Parallel Fast Orientations from the Mantle Wedge Tip to the Backarc. the Dramatic Change in …

Descriptive Statistical Analysis Of Experimental Data For Wettability Alteration With Smart Water Flooding In Carbonate Reservoirs, Muhammad Ali Buriro, Mingzhen Wei, Baojun Bai, Ya Yao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Smart water flooding is a promising eco-friendly method for enhancing oil recovery in carbonate reservoirs. The optimal salinity and ionic composition of the injected water play a critical role in the success of this method. This study advances the field by employing machine learning and data analytics to streamline the determination of these critical parameters, which are traditionally reliant on time-intensive laboratory work. The primary objectives are to utilize data analytics to examine how smart water flooding influences wettability modification, identify key parameter ranges that notably alter the contact angle, and formulate guidelines and screening criteria for successful lab design. …

Lessons Learned From Laboratory Study And Field Application Of Re-Crosslinkable Preformed Particle Gels Rppg For Conformance Control In Mature Oilfields With Conduits/Fractures/Fracture-Like Channels, Baojun Bai, Thomas P. Schuman, David Smith, Tao Song

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

This Paper Surveys the Role of Re-Crosslink able Preformed Particle Gels (RPPG) in Addressing Conformance Challenges within Mature Oilfields. Despite Widespread Preformed Particle Gel (PPG) Application in 15,000+ Wells, their Limitations in Sealing Fractures and Conduits Prevalent in Mature Reservoirs Have Driven the Development of RPPG Formulations. Synthesized in Various Sizes from Micrometer to Millimeter Levels, These Environmentally Friendly RPPGs Are Tailored for Diverse Reservoir Conditions. Findings Showcase the Successful Laboratory-Scale Creation and Upscaling of RPPG Products, Offering Adaptability to Temperatures from 20 to 175°C, Customizable Sizes, Swelling Ratios (5 to 40 Times), and Re-Crosslinking Times Spanning Minutes to Days. …

Electromagnetic Near-Field Scanning With A Spatially Sparse Sampling Strategy Utilizing Kriging-Dmd, Yanming Zhang, Steven Gao, Lijun Jiang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

This paper proposes a hybrid method for time-resolved electromagnetic near-field scanning, merging model-based (Gaussian processes regression model, a.k.a. Kriging method) and data-driven (dynamic mode decomposition) techniques. Specifically, Latin hypercube sampling enables spatially sparse measurements, followed by dynamic mode decomposition to analyze resulting sparse spatial-temporal data, extracting frequency information and sparse dynamic modes. The Kriging method is then employed for full-state reconstruction. The proposed approach is evaluated using crossed dipole antennas. Results indicate that, even with a spatial subsampling factor of 130, achieving a fully reconstructed field distribution suitable for engineering applications with frequency information extraction is feasible. This hybrid framework …

Would Self-Supported Fracture Contribute To The Hydrocarbon Production In Shale Reservoir Besides Proppant-Supported Fracture, Y. Sun, G. Li, S. Zeng, J. Wu, J. Liu, M. Xu, C. Dai, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

During hydraulic fracturing in deep shale gas reservoirs, it is difficult to pump proppants long distances, and self-supported fractures are formed at the far and upper ends of the fractures. The self-supported fracture could hold the fracture space by its surface structure again fracture closure. However, it faces various aspects of impairment during shale gas reservoir development, which affect its conductivity. Among the impairment, long-term production results in a decline of bottom hole pressure, which will compact the fracture space, and self-supported fractures without proppant are more sensitive than those with proppant. In this paper, we conducted a series of …

Fiber Assisted Re-Assembly Preformed Particle Gel For Conformance Control, Zhe Sun

Masters Theses

"In Enhanced Oil Recovery technology today, gel treatments have been implemented as a cost-effective method to improve the oil sweep efficiency in reservoirs by plugging the high permeability zones. This study presents a novel gel composition to be used in conformance control in order to improve oil recovery for mature oilfields.

The product is a fiber-assist re-assembly preformed particle gel which could be generalized to the preformed particle gels (PPG). The product developed in this study could be injected into the reservoir act as a conformance control agent by plugging water thief zones and channels in the beginning process. Due …

Fe-Ni-Cu-Pge Sulfide Transport Mechanisms And Carbon-Sulfur Interactions In Lower Crustal Magmatic Settings: A Study From The Valmaggia Ultramafic Pipe, Ivrea-Verbano Zone, Italy, Shelby Leann Clark

Masters Theses

"Constraining the processes that control the transport and deposition of sulfides in the deep lithosphere is an important step in expanding ore deposit exploration search space to include exhumed lower crustal rocks. The ultramafic sulfide ore-bearing Valmaggia pipe in the Ivrea-Verbano Zone of NW Italy, an exhumed cross section of the overlying lower continental crust and subcontinental lithospheric mantle, gives critical insight into metallogenic processes in lower crustal settings. The ~300 m wide metasomatized pipe hosts Fe-Ni-Cu-(PGE±Co±Au) sulfide mineralization that is commonly associated with locally abundant carbonates and hydrous silicates (phlogopite, amphibole). Previous studies suggested that sulfides were physically transported …

Descriptive Statistical Analysis Of Experimental Data For Wettability Alteration With Smart Water Flooding In Carbonate Reservoirs, Muhammad Ali Buriro, Mingzhen Wei, Baojun Bai, Ya Yao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Smart water flooding is a promising eco-friendly method for enhancing oil recovery in carbonate reservoirs. the optimal salinity and ionic composition of the injected water play a critical role in the success of this method. This study advances the field by employing machine learning and data analytics to streamline the determination of these critical parameters, which are traditionally reliant on time-intensive laboratory work. the primary objectives are to utilize data analytics to examine how smart water flooding influences wettability modification, identify key parameter ranges that notably alter the contact angle, and formulate guidelines and screening criteria for successful lab design. …

Development Of Tio2/Nh2-Mil-125 Nanocomposite For The Removal Of Ciprofloxacin Under Induced Solar Irradiation, Bilkis Mojisola Ajiwokewu

Theses

This research focuses on the development and application of Metal-Organic Frameworks (MOFs)-based nanocomposites for the photocatalytic removal of pharmaceutical contaminants, with a specific emphasis on ciprofloxacin (CIP). The photocatalytic degradation of CIP was investigated using as-synthesized photocatalysts of TiO₂ nanowires (TiO₂NWs), bare MOF of NH₂-MIL-125, TiO₂NW/NH₂-MIL-125 composite, and Lanthanum (La)-doped composite. Intriguingly, the TiO₂NW/NH₂-MIL-125 composite exhibited the highest efficiency, achieving a photodegradation rate of 0.0111 min-1, surpassing the independent performances of bare MOF of NH₂-MIL-125 and TiO₂NW. The observed efficiency was attributed to …

Evaluation Of Novel Preformed Particle Gel System For Conformance Control In Mature Oil Reservoirs, Abdulaziz Almakimi, Ahmed Ben Ali, Ibnelwaleed A. Hussein, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

To address challenges associated with excessive water production in mature oil reservoirs, this study introduces a carboxymethyl cellulose (CMC)-based material as a novel preformed particle gel (PPG) designed to plug excessive water pathways and redistribute the subsequent injected water toward unswept zones. Through microwave-assisted grafting copolymerization of CMC with acrylamide (AM), we successfully generated multi-sized dry particles within the range of 250–800 µm. Comprehensive analyses, including Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), have confirmed the chemical composition and morphology of the resulting carboxymethyl cellulose-grafted crosslinked polyacrylamide (CMC/PAMBA). Swelling kinetics and rheology tests were conducted to confirm the …

Carbon Dioxide Gasification Of Biochar: A Study On Utilizing Captured Co2 To Mitigate Greenhouse Gas Emission And Improving Carbon Conversion Efficiency, Nnamdi Ofuani

College of Graduate Studies: Theses & Dissertations

With rapidly growing global economies and world population, fossil fuel continues to play a major role in meeting current energy demands. Carbon capture and storage (CCS) technologies have, hence, been implemented to reduce CO₂ emissions in the atmosphere. With the implementation of CCS technologies comes the need to utilize the captured CO₂. This research, therefore, proposes CO₂ gasification of biochar as a viable carbon utilization pathway. With captured CO₂ coming at various concentrations, there is a need to understand how CO₂ concentration affects biochar conversion to useful products. This study, therefore, evaluates the effects …

Investigations Of Performance And Emissions Of A Fischer-Tropsch Gtl Sustainable Aerospace Fuel With Lubricity Improver In A Compression Ignition Engine With Butanol Port Fuel Injection, James B. Willis

College of Graduate Studies: Theses & Dissertations

As there is increasing concern over emissions of traditional fossil fuels, as well as the future of continued reliance on this dwindling resource, it is becoming increasingly evident that alternative fuels are a necessity. This research investigates the use of a Fischer-Tropsch fuel from natural gas feedstocks, S8, in an internal combustion research engine with a common rail fuel injection system. This synthetic kerosene fuel has a high DCN of 62, indicating high affinity to autoignition compared to conventional pump diesel (ULSD) at 48 DCN. However, due to the process by which it is produced, this fuel lacks the necessary …

The Comprehensive Study Of High Viscosity Friction Reducers In High-Tds And High-Temperature Environments, Xiaojing Ge

Doctoral Dissertations

"High viscosity friction reducers (HVFRs) have been recently gaining more attention and increasing in use, not only as friction-reducing agents but also as proppant carriers. Reusing of produced water has also been driven by both environmental and economic benefits. Currently, most friction reducers on the market are anionic friction reducers, which are fully compatible with most produced water with low to medium level of Total Dissolved Solids (TDS) but show a significant drop at high TDS conditions in term of their friction reduction performance in most cases. On the contrary, cationic friction reducers are believed to have better TDS tolerance …

Investigation Of Operational Parameter Differences Between The Standard Ron Test Method And Knock-Limited Modern Spark-Ignition Engine Operation, Alexander Hoth

Dissertations, Master's Theses and Master's Reports

Octane numbers (ONs) are used worldwide to rate the knock propensity of gasoline-like fuels for spark-ignition engines, making ONs the leading indicator of fuel quality for commercial distribution. The ONs were established 90 years ago and have only received minor changes compared to significant advancements in modern engine operation and fuel composition. This has resulted in discrepancies between knock-limited modern engine operation and standard ON ratings. This dissertation used a standard CFR octane rating engine at Argonne National Laboratory that was instrumented with modern combustion research tools to investigate key differences between the Research Octane Number (RON) rating conditions and …

Lithospheric Drip And Mantle Thermal Upwelling Beneath Central Asia And The Southern Great Plains Of North America: Evidence From Receiver Function Imaging, Yangyang Liao

Doctoral Dissertations

"Investigating the depth of mantle transition zone (MTZ) discontinuities provides insights into mantle dynamics, including regional-scale downwelling of mantle lithosphere (i.e., lithospheric drip) and upwelling of thermal materials (i.e., mantle plume). In our study, we employ receiver functions to image the 410 km (d410) and 660 km (d660) mantle discontinuities and to ascertain thickness of the MTZ beneath Central Asia and the Great Plains in United States. The findings unveil a significantly thickened transition zone, exhibiting an average thickness of 284 km beneath East Sayan. When considered alongside geochemical observations, our results indicate that the descent of the lithosphere is …

Exploring Seismic Anisotropy In The Crust And Mantle Of The Tibetan Plateau And Analyzing Seismic Velocity Variations In Yellowstone, Cong Shen

Doctoral Dissertations

"Seismology is a scientific discipline that utilizes seismic waves to investigate the deep structures within the Earth's interior, which are otherwise inaccessible to direct observation by humans. These seismic waves can be categorized into two types: body waves and surface waves, each with distinct propagation modes and behaviors, carrying valuable information about their travel paths. The first paper concentrates on the analysis and inversion of body waves produced by large seismic events. It employs shear wave splitting and receiver function methods to explore the geodynamic structure of the south-central Tibetan Plateau, near the plate boundary. The investigation covers the depth …

Topography Of The 410 And 660 Km Discontinuities Beneath The Tibetan Plateau And Adjacent Areas, Zexin Miao

Doctoral Dissertations

"The Tibetan Plateau represents the ongoing geotectonic aftermath of a continental collision initiated approximately 65 million years ago. Despite numerous seismological studies, controversies remain regarding the structure, evolution, and dynamics of the crust and mantle beneath Tibetan Plateau. In this study, we used teleseismic broadband data to investigate the topography of the mantle transition zone (MTZ) discontinuities. A total of ~655,000 receiver functions from 735 stations was utilized to image the 410 and 660 km discontinuities bordering the MTZ. Combining the observed and velocity corrected results, several areas in the central Tibet exhibit a typical d410 and an anomalously deep …