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A review of torsional vibration mitigation techniques using active control and machine learning strategies

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PETROLEUM 2024年第3期10卷 411-426页

作者： Sharma, Aditya Abid, Khizar srivastava, Saket velasquez, Andres Felipe Baena Teodoriu, Catalin Univ Oklahoma Norman OK 73019 USA

Drilling is one of the most challenging and expensive processes in hydrocarbon extraction and geothermal well development. Dysfunctions faced during drilling can increase the non-productive time (NPT) greatly, resulting in inflating the drilling cost and also pose a safety concern. One of the main problems faced during drilling that limits the life of drilling equipment and tools and decreases the overall productivity of the system is drilling vibrations. These vibrations can be categorized into three modes: axial, lateral, and torsional. Stick-slip vibrations are a type of torsional vibration in which the bottom hole assembly (BHA) periodically stops to rotate followed by a spike in the bottom hole RPM. This paper provides a comprehensive review of techniques used to control and mitigate torsional vibration with an emphasis on stick-slip. A brief introduction to drillstring and friction modeling is presented followed by a concise summary of passive control techniques to control stick-slip. Then the focus is shifted to an up-to-date review of active control and machine learning for stick-slip control and mitigation. The paper ultimately highlights the importance of adapting novel control and mitigation concepts to improve stick slip detection and improve the overall drilling process. A unique solution is insufficient to control a complex process such as drilling, but integration of various techniques has been found promising. (c) 2023 Southwest Petroleum University. Publishing services by Elsevier B.v. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http:// ***/licenses/by-nc-nd/4.0/).

关键词： Drilling vibrations Controllers Mitigations strategies Stick slip Torsional vibrations Machine Learning STICK-SLIP OSCILLATIONS DRILLSTRING vIBRATION BENDING vIBRATIONS OUTPUT-FEEDBACK DRAG BITS DESIGN SUPPRESSION STABILITY SYSTEM MODEL

Tribological behaviour of C/C-SiC composites-A review

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Journal of Advanced Ceramics 2016年第1期5卷 1-12页

作者： Parshant KUMAR v.K.srivastava Department of Mechanical Engineering Indian Institute of Technology(BHU) Varanasi-221005 India

Ceramic matrix composites made of carbon fibres and carbon matrix (C/C) are generally used for aircraft structures and brake discs due to their low density, and good thermal, mechanical, and tribological properties. Silicon carbide (SiC) can be introduced to the matrix to improve the performance of C/C composites, because it increases the hardness and thermal stability, and decreases the chemical reactivity, which leads to the improvement of tribological properties of C/C composites. Thus carbon–carbon silicon carbide (C/C–SiC) composites can be used at high temperature for the application of brake discs, friction clutches, etc. C/C–SiC composites are fabricated by three different methods: (i) chemical vapour infiltration (CvI), (ii) polymer infiltration and pyrolysis (PIP), and (iii) liquid silicon infiltration (LSI), among which LSI method is widely used for the fabrication of C/C–SiC composites due to higher mechanical and thermal properties.

关键词： carbon-carbon (C/C) composites coefficient of friction wear

Application of IITM-RANS3D to free-fall water entry of prismatic and non-prismatic finite wedges

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水动力学研究与进展B辑:英文版 2023年第3期35卷 417-430页

作者： Shaswat Saincher Kshitij srivastava R.vijayakumar v.Sriram Center for Maritime Experiments to Maritime Experience(ME2ME) Indian Institute of Technology MadrasChennaiIndia Department of Ocean Engineering Indian Institute of Technology MadrasChennaiIndia

High-speed watercraft and ships undergo coupled motions which make the front portion of the hull exit and violently re-enter *** induces short-term slamming loads that may compromise the structural integrity of the *** slamming of the bow can be modeled as straight wedges of different deadrise angles(DRAs)falling into water from different *** advent of computational fluid dynamics has allowed the problem of wedge-slamming to be simulated using the full Navier-Stokes equations thus complementing the pioneering studies based on ***,most researchers are opting to use commercial software to simulate the wedge-impact problem as it allows access to overset meshing algorithms which are robust in modeling the wedge as a moving *** boundary methods(EBMs)offer some advantages over overset meshing in that the mesh only needs to be generated once and Cartesian mesh-based solvers can be ***,the application of EBMs to wedge-impact has been limited in the literature and merits further *** this context,we investigate the applicability of the fast-fictitious-domain(FFD)based embedded boundary treatment to simulate the violent water-entry of *** extend our in-house Navier-Stokes model IITM-RANS3D to handle floating bodies through integration of a rigid-body dynamics solver and an algorithm to embed three-dimensional stereolithography(STL)geometries as solids over a Cartesian *** proposed algorithm is extensively benchmarked against variable DRA wedge-slamming experiments reported in the literature as well as constant DRA wedge-slamming experiments performed *** good agreement is reported in terms of the time-history of hydrodynamic impact pressures measured at various locations on the hull as well as the wedge motion responses thus demonstrating the suitability of FFD for simulating the coupled hydrodynamics of slamming for simplified hull geometries.

关键词： Wedge water entry slamming fast-fictitious-domain IITM-RANS3D experiments

Compositionally Graded Microstructure for Ag-Fe Nanoparticles

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Nano-Micro Letters 2012年第3期4卷 172-175页

作者： Chandan srivastava K.v.L.Sushma Department of Materials Engineering Indian Institute of Science

Ag-Fe nanoparticles with a highly Ag rich average composition were synthesized by the sonochemical ***-iron system exhibits a wide miscibility gap in the bulk ***,a graded compositional profile along the nanoparticle radius was *** at and near the surface of the nanoparticle contained both Ag and Fe *** composition got relatively deficient Fe towards the center of the particle with particle core made up of pure *** of Ag and Fe is confirmed by the absence of diffraction signal corresponding to pure Fe phase and presence of a paramagnetic phase in nanoparticles containing a diamagnetic(Ag)and ferromagnetic(Fe)elements.

关键词： Nanoparticles Electron Microscopy Ag-Fe Miscibility gap Solid solution Microstructure

Effect of hydrogen plasma treatment on the growth and microstructures of multiwalled carbon nanotubes

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Nano-Micro Letters 2010年第1期2卷 42-48页

作者： S.K.srivastava v.D.vankar v.Kumar Department of Physics Indian Institute of Technology Delhi National Physical Laboratory Dr.K.S.Krishnan Marg

The effect of hydrogen plasma treatment of iron oxide films on the growth and microstructure of carbon nanotubes(CNTs)by microwave plasma enhanced chemical vapor deposition process has been *** plasma was characterized in-situ using optical emission *** of the films was examined by scanning electron *** analysis was carried out by high resolution transmission electron microscopy(HRTEM)equipped with energy dispersive X-ray spectroscopy(EDS)and micro-diffraction *** is found that oxide films without H_2 plasma pretreatment or treated for lesser time resulted in CNT films with high percentage of carbonaceous particles and with embedded particles/nanorods distributed discontinuously in the cavity of the *** embedded particles were found to be of iron carbide(Fe-C)as confirmed by HRTEM,EDS and micro-diffraction *** observations suggested that the iron oxide particles had poor catalytic action for CNT growth and in-situ reduction of oxide clusters to Fe by hydrogen plasma plays a key role in discontinuous filling of the nanotubes by the catalytic particles.

关键词： Carbon nanotubes Chemical vapor deposition Iron carbide MPECvD

Investigating the impact of atmospheric parameters on sea ice variability in and around Svalbard

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Advances in Polar Science 2023年第2期34卷 125-143页

作者： Dency v PANICKER Bhasha vACHHARAJANI Rohit srivastava Department of Physics School of Energy TechnologyPandit Deendayal Energy UniversityGandhinagarGujaratIndia Department of Mathematics School of TechnologyPandit Deendayal Energy UniversityGandhinagarGujaratIndia

Recent research has shown that winter warmings are phenomenally high compared to summer warmings over the poles,especially over the *** the current scenario into account,this paper attempts to understand the atmospheric variables causing sea ice variability over and around the region of Svalbard for seasons;winter,spring,summer and autumn for the span of 42 years(1979-2021).The variability in atmospheric and oceanic parameters namely temperature,precipitation,wind speed,and sea surface salinity are analysed over inter-spatial,inter-seasonal and inter-annual *** are characterized by inter-annual increasing trend in *** 1981-1990 the rise from the decadal mean is found to be 0.39 K·a^(-1),during 1991-2000 it is 0.20 K·a^(-1),during 2001-2010 it is 0.04 K·a^(-1) and during 2011-2020 it is 0.23 K·a^(-1).Interestingly while considering inter-spatial domains,the region southwest to Svalbard seems to be wetter(0.05 mm·(10 a)-1)compared to its northeast(-0.03 mm·(10 a)-1).Across all the three domains,wind speeds are highest during autumn and then decrease subsequently through summer,spring and are least during *** is predominantly from the south,and hence it is suspected to carry hot Atlantic ***,the significant role of salinity in the ocean also plays a key role in governing the fate of sea ice *** long-term forecasts of temperature over seaice of Svalbard are alarming especially for the winter ice(r=-0.84).Correlation matrices between atmospheric and sea ice parameters are shown to gain a better understanding on their inter relation.

关键词： Svalbard northeast Svalbard southwest Svalbard temperature precipitation wind speed sea ice concentration

Photoconductivity and surface chemical analysis of ZnO thin films deposited by solution-processing techniques for nano and microstructure fabrication

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Journal of Semiconductors 2013年第3期34卷 12-16页

作者： v.K.Dwivedi P.srivastava G.vijaya Prakash Nanophotonics Laboratory Department of PhysicsIndian Institute of Technology DelhiHauz khasNew Delhi-110 016India Nanostech Laboratory Department of PhysicsIndian Institute of Technology DelhiHauz khasNew Delhi-110 016India Nanophotonics Laboratory Department of PhysicsIndian Institute of Technology DelhiHauz khasNew Delhi-110016India

The fabrication of zinc oxide(ZnO) from inexpensive solution-processing techniques,namely,electrochemical deposition and electrospinning were explored on various conducting and mesoporous semiconducting *** conditions were derived for template- and self-assisted nano/micro structures and composites. ZnO thin films were annealed at a fixed temperature under ambient conditions and characterised using physical and optical *** photocurrent response in the Uv region shows a fast rise and double decay behaviour with a fast component followed by a slow oscillatory *** results were correlated with surface chemical analysis from X-ray photoelectron *** characterisation details reveal the importance of fabrication parameter optimisation for useful low-cost optoelectronic applications.

关键词： zinc oxide electrochemical deposition surface analysis X-ray photoelectron spectroscopy photocurrent response optoelectronic applications

Pd-gate MOS sensor for detection of methanol and propanol

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Journal of Natural Gas Chemistry 2011年第2期20卷 123-127页

作者： Preeti Pandey J. K. srivastava v. N. Mishra R. Dwivedi Center for Research in Microelectronics Department of Electronics Engineering Institute of Technology Banaras Hindu University

The present paper focused on the detection of methanol and propanol using Pd-gate metal-oxide-semiconductor （MOS） sensor. Surface mor- phology and composition of the gate film were studied by scanning electron microscopy （SEM） and atomic force microscopy （AFM）. The response of the sensor for propanol and methanol was measured as shift in capacitance-voltage （C-v） and conductance-voltage （G-v） curves of the MOS structure. The sensitivity of the sensor towards methanol was found to be greater than that towards propanol. It was 58.2% for methanol and 32% for propanol （at 0.6 v, 1 MHz） in terms of capacitance measurements, while in terms of conductance results the sensitivity was found to be 57.2% for methanol and 38.9% for propanol at 1 kHz. The discontinuities or cracks present in the microstructure of the gate material are believed to be mainly responsible for the high sensitivity of the sensor, going with the decomposition of gas molecules and subsequent hydrogen permeation through Pd.

关键词： MOS structure gas sensor palladium cracks sensitivity

Structural and micro structural studies of PbO-doped SnO_2 sensor for detection of methanol, propanol and acetone

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Journal of Natural Gas Chemistry 2011年第2期20卷 179-183页

作者： J. K. srivastava Preeti Pandey v. N. Mishra R. Dwivedi Center for Research in Microelectronics Department of Electronics Engineering Institute of Technology Banaras Hindu University

In the present work the structural information of PbO-doped SnO2 thick film sensor has been investigated with X-ray diffractometer （XRD） and scanning electron microscope （SEM）. Initially, SnO2 powder was derived using sol-gel process and was subsequently doped with PbO and ground up to nanosized particles. A suitable gas sensor structure was fabricated on 1′′×1′′ alumina substrate using thick film technology. The necessary paste for screen printing was also developed. SEM results showed sol-gel derived powder gets more agglomerated in the thick film form. The sensitivity of the sensor has been investigated at different temperatures （150 ？C？350 ？C） upon exposure to methanol, propanol and acetone, yielding a maximum at 250 ？C for acetone with 1 wt% PbO-doping while at 350 ？C for propanol with 3 wt% PbO-doping of the sensor. The reduction of particle size to nanometers （validated through XRD） leads to a dramatic improvement in sensitivity of sensors for the chosen organic vapors. The results also correlate well with the microstructural properties of the material and the dopant.

关键词： gas sensor nanosized SnO2 Sol-gel thick film