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SSrN 2023年

作者： Yang, Yuqi Wang, Zizhen Wan, Guangze Liu, Zhengxiao Zhang, Haipeng Fu, Yuequn Ariane, Essouma E.F.B. Liu, Jian Xing, Tingyan Zhang, Shiling China University of Petroleum–Beijing at Karamay Karamay834000 China Institute of Unconventional Oil and Gas Science and Technology China University of Petroleum Beijing102249 China School of Information Engineering China University of Geosciences Beijing100083 China CNPC Engineering and Technology R&D Company Limited Beijing Beijing102200 China PoreLab The Njord Centre Department of Physics University of Oslo Oslo0371 Norway State Key Laboratory of Heavy Oil Processing China

Multi-phase microfluidic transport is a topic of great interest in both academic research and industry. This study focuses on the deformation dynamics of bubbles generated during oil transport in microchannels. We investigate the deformation behavior of bubbles in square microchannels with two semi-cylinders. Our findings show that bubble deformation occurs in two modes: breakup deformation and elastic nonbreakup deformation. By evaluating the minimum width of the microchannel neck, we divide both modes into four stages, which exhibit power-law variation. Additionally, we investigate the effects of presetting factors on viscosity in the microchannel. To gain deeper insights into the deformation mechanism of bubbles, we use micro-PIV to describe the velocity patterns and dimensional distribution of viscosity in the flow. We successfully summarize a dynamical scaling law that specifies the size of bubbles formed in the pore throat microchannels. It reveals that the fluid characteristic of the continuous phase dominates the deformation of bubbles in such microdevices. Moreover, we developed the rosin-rammler regression models to predict droplet size and neck width formation in the continuous liquid at microchannels, which we compare with experimental data. results of the analytical model show that microchannel shape and droplet volume play important roles in the droplet deformation process. © 2023, The Authors. All rights reserved.

关键词： Microchannels

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Experimental demonstration of multiparty reference-frame-independent QKd

Experimental demonstration of multiparty reference-frame-ind...

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Conference on Lasers and Electro-Optics (CLEO)

作者： donghwa Lee Kyujin Shin Yosep Kim Hyang-Tag Lim Yong-Su Kim Center for Quantum Information Korea Institute of Science and Technology (KIST) Seoul Republic of Korea Division of Nano & Information Technology KIST School Korea University of Science and Technology Seoul Republic of Korea Materials Research & Engineering Center R&D Division Hyundai Motor Company Uiwang Republic of Korea

We report that rFI-QKd protocol can be extended to multiparty system using Greenberger-Horne-Zeilinger (GHZ) state. We derive the asymptotic key rate and perform proof-of-principle experiment to verify the feasibility... 详细信息

ISBN: (纸本)9781957171258

关键词： Optical fibers Photonic entanglement Quantum communications Quantum key distribution Quantum networks Single photon detectors

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An On-Line Inductance Identification Method for Permanent Magnet Synchronous Motors Under Sensorless Control in The Full Speed domain

An On-Line Inductance Identification Method for Permanent Ma...

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International Conference on Power Electronics and Motion Control (IPEMC)

作者： Yue Liu Liguo Wang Qiang Gao Yong Li Fei E Department of Electrical Engineering Shanghai Jiao Tong University Shanghai China State Grid Suzhou Power Supply Company Substation Maintenance Center Suzhou China Department of R&D Contemporary Amperex Electric Vessel Technology Co. Limited Ningde China Department of Technology Contemporary Amperex Electric Vessel Technology Co. Limited Ningde China

ISBN: (数字)9798350351330

ISBN: (纸本)9798350351347

This work presents an online inductance identification method for permanent magnet synchronous motors in the full speed domain. Online inductance estimation is realized by injecting two modified high-frequency square wave voltage signals into the d-q axis simultaneously. This method can achieve high-precision identification of inductance in the full sensorless speed domain. The simulation results show that the inductance identification accuracy of this method can reach ±4% whether under constant loading, sudden addition and subtraction loading or dynamic loading.

关键词： Inductance Accuracy Simulation Loading Asia Estimation Sensorless control

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Experimental study on the creep behavior of shale in uniaxial compression test 54

Experimental study on the creep behavior of shale in uniaxia...

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54th U.S. rock Mechanics/Geomechanics Symposium

作者： Gao, dewei Yang, Henglin dong, Jingnan Chen, Mian Hou, Yanan Li, Jun Sichuan Changning Natural Gas Development Co. LTD Chengdu China CNPC Engineering Technology R&D Company Limited Beijing China Beijing China China University of Petroleum-Beijing Beijing China

In oil and gas well engineering, shale creep plays an important role in both the borehole stability and the crack closure of the after-fracturing process. In this study, the creep behavior of matrix shale in uniaxial compression test is experimentally examined. Both uniaxial compression tests and uniaxial compression creep tests are conducted on small-scale specimens using Gatan micro-testing system. Several constant-load stages are carried out before the stress raise above the threshold. The results show that the matrix shale have a creep threshold, below which the specimens exhibit distinct primary creep stage and secondary creep stage. Above the threshold, the specimen is in accelerated stage, in which the creep strain increased in an exponential manner. results also show that the specimens of regular uniaxial compression strength tests conducted within several minutes exhibited one main crack, which dominated the failure pattern. The specimens of creep tests that are conducted over tens of hours are crushed into lots of fine parts. The development of micro cracks dominates in the creep tests. The comparison between uniaxial compressive strength and creep threshold value show that the threshold value may be higher than the UCS value if the specimen is in constant-load mode for tens of hours. The results are limited to USC tests because the propagations of the microcracks might be hindered in triaxial tests. This study provides evidence of the subcritical propagation and blunting of the micro cracks in creep test. The results also provide better understanding of the creep shale behavior under uniaxial compression. It may help researchers know more about the creep behavior of well borehole and the crack closure of shale. © 2020 ArMA, American rock Mechanics Association

关键词： Creep

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Nano-Emulsification Method as a Strategy for Oil Soluble Corrosion Inhibitor Transform to Water Soluble

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SSrN 2023年

作者： Jiang, Jingjing Tang, Yongfan Huang, Lihua Peng, Lincai Xu, Yong Wei, Guofeng Li, Yinan Research Institute of Natural Gas Technology PetroChina Southwest Oil and Gasfield Company Sichuan Chengdu China National Energy R&D Center of High Sulfur Gas Exploitation Sichuan Chengdu China High Sulfur Gas Exploitation Pilot Test Center CNPC Sichuan Chengdu China PetroChina Southwest Oil and Gasfield Company Sichuan Chengdu China Central Sichuan Oil and Gas District PetroChina Southwest Oil and Gasfield Company Sichuan Suining China

One of the most economical and effective approaches to protecting metal pipes in the oil and gas industries is to employ corrosion inhibitors. The solubility or dispersity of many corrosion inhibitors with long alkyl chains in aqueous water, however, presents a challenge. In this study, nano-emulsification technique was developed to improve the corrosion inhibitors' dispersity in corrosive water. Using dynamic light scattering (dLS), the influence of formulation on the droplet diameter was investigated, and the dispersion in the water was visually examined. Then, using weight loss measurements and electrochemical tests, the inhibition performances and mechanisms in the H2S/CO2 containing 5.0 wt% NaCl solution were investigated. The morphology and composition of corrosion products were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) methods. The results of the comparison investigation demonstrated that, in terms of inhibition efficiency, the corrosion inhibitor encapsulated in nanoemulsions was comparable to the system employing ethanol and liquid paraffin as solvents, both exceeding 90%. Moreover, its dispersion performance in water was significantly better than that of the paraffin oil system, and the required injection amount was considerably lower than that of the ethanol system. Further experimental results indicated that the nanoemulsion system was more consistent with the Freundlich adsorption model, unlike the other two systems which follow the Langmuir adsorption model. Finally, the SEM and XPS results demonstrated that the nanoemulsion system does not change the material type of corrosion products, but it seems to have a visible influence on the morphology. These findings suggest that nano-emulsification technique has the potential to be improved the solubility or dispersity of oil soluble corrosion inhibitor, which can extend its application fields. © 2023, The Authors. All rights reserved.

关键词： Corrosion inhibitors

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Challenge of temperature control for downhole instruments in HTHP reservoir

Challenge of temperature control for downhole instruments in...

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SPE Offshore Europe Conference and Exhibition 2019, OE 2019

作者： Gao, Wenkai Liu, Ke Jia, Hengtian Hong, difeng Teng, Xinmiao CNPC Engineering Technology R and D Company Limited

ISBN: (纸本)9781613996645

With the further exploration of oil and gas, we have to search for new resources which buried in deep strata, and most of the deep and ultra-deep wells are categorized in high-pressure/high-temperature (HPHT) wells. The problem of high temperature and the challenge to the existing downhole equipments are becoming increasingly prominent, where the drilling depth is severely restricted. The conventional measurement while drilling tools with common electronics will experience very high failure rates at these conditions. One of the solutions is called the active cooling technology, which can transfer the heat from electronics system to downhole environment. By this way, the temperature control of downhole instrument circuit system is realized. The active cooling technology is expounded in this paper, expecially about the principles and development status of each system. After evaluating and analyzing the characteristics of this technology, the function of heat transfer and constituent elements for the cooling system are summarized. The study from this work demonstrates the future work for downhole cooling technology: large refrigeration capacity, small size, strong adaptability and modularization. Copyright 2019, Society of Petroleum Engineers

关键词： Instrument circuits

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A three dimensional visualized physical simulation for natural gas charging in the micro-nano pore system

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Petroleum Exploration and development 2022年第2期49卷 349-362页

作者： QIAO Juncheng ZENG Jianhui XIA Yuxuan CAI Jianchao CHEN dongxia JIANG Shu HAN Guomeng CAO Zhe FENG Xiao FENG Sen- State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing 102249.China College of Geosciences China University of PetroleumBeijing 102249China Institute of Geophysics and Geomatics China University of GeosciencesWuhan 430074China Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education China University of GeosciencesWuhan 430074China Dagang Oilfield Company PetroChinaTianjin 300280China Sinopec Petroleum Exploration and Production Research Institute Beijing 102206China CNPC Engineering Technology R&D Company Limited Beijing 102206China

A micro-nano pore three-dimensional visualized real-time physical simulation of natural gas charging, in-situ pore-scale computation, pore network modelling, and apparent permeability evaluation theory were used to investigate laws of gas and water flow and their distribution, and controlling factors during the gas charging process in low-permeability(tight) sandstone reservoir. By describing features of gas-water flow and distribution and their variations in the micro-nano pore system, it is found that the gas charging in the low permeability(tight) sandstone can be divided into two stages, expansion stage and stable stage. In the expansion stage, the gas flows continuously first into large-sized pores then small-sized pores, and first into centers of the pores then edges of pores;pore-throats greater than 20 μm in radius make up the major pathway for gas charging. With the increase of charging pressure, movable water in the edges of large-sized pores and in the centers of small pores is displaced out successively. Pore-throats of 20-50 μm in radius and pore-throats less than 20 μm in radius dominate the expansion of gas charging channels at different stages of charging in turn, leading to reductions in pore-throat radius, throat length and coordination number of the pathway, which is the main increase stage of gas permeability and gas saturation. Among which, pore-throats 30-50 μm in radius control the increase pattern of gas saturation. In the stable stage, gas charging pathways have expanded to the maximum, so the pathways keep stable in pore-throat radius, throat length, and coordination number, and irreducible water remains in the pore system, the gas phase is in concentrated clusters, while the water phase is in the form of dispersed thin film, and the gas saturation and gas permeability tend stable. Connected pore-throats less than 20 μm in radius control the expansion limit of the charging pathways, the formation of stable gas-water distribution, and the ma

关键词： low permeability(tight)sandstone gas charging three-dimensional visualization physical simulation micro-nanometer pore network gas and water flow and distribution

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Optimizing Parameters of Two-Stage Pdc Bit in deep Formation Applications

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SSrN 2023年

作者： Chen, Zhenliang Shi, Huaizhong Zhao, Heqian Huang, Zhongwei He, Wenhao Chen, Han Yu, Chao Zhang, Bo State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum-Beijing Beijing102249 China CNPC Engineering Technology R&D Company Limited Beijing Petroleum Machinery Co. Ltd Beijing102206 China Beijing Key Laboratory of Optical Detection Technology for Oil and Gas China University of Petroleum-Beijing Beijing102249 China Department of Civil and Environmental Engineering University of Alberta EdmontonABT6G 2G7 Canada

Two-stage PdC (Polycrystalline diamond compact) bit is a special drilling bit consisting of a small-diameter pilot and a large-diameter reamer. The unique rock-breaking structure is designed to improve the drilling efficiency and reduce drilling costs in deep and abrasive formations. According to previous studies, the hydraulic structure of the two-stage PdC bit can significantly affect the drilling performance of removing cuttings near the bottom of the wellbore. Therefore, this research has proposed to achieve a high efficiency of cuttings removal by optimizing the hydraulic structure. In this paper, the flow field at the bottom of the well near the two-stage PdC bit (Φ171.45 mm pilot + Φ215.9 mm reamer) has been numerically studied using the finite element method. As shown in the analysis results, both the flow rate of the pilot and the flow rate ratio of the pilot to the reamer increase significantly with the increase of the area ratio of the pilot nozzles to the total nozzles. The numerical data supports that the cuttings can be removed effectively from the bottom of the wellbore when the area ratio is between 0.75 and 0.80. Moreover, the cuttings can be removed effectively from the bottom of the wellbore when the mud viscosity is about 10 mPa·s, the rate of penetration is between 4 and 8 m/h, the drill speed is 90rpm and the cuttings particle sizes is between 1 and 2 mm. Besides, increasing the pump rate can imporve the cutting-carrying efficiency through the wellbore bottom. Field test results indicate that the average penetration rate of the test interval is increased by 30% and the footage of the test interval is increased by over 40% compared to the adjacent interval of the same well. This study can provide guidance for the optimal design of the hydraulic structure of such two-stage PdC bits. © 2023, The Authors. All rights reserved.

关键词： reamers

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Study on the Sealing Performance of a Composite Plugging System Comprising Cement and Sn58Bi Alloy for Wellbore Applications

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Materials (Basel, Switzerland) 2025年第10期18卷 2301页

作者： Chunqing Zha Zhengyang Zhang Wei Wang Gonghui Liu Jun Li Wei Liu College of Mechanical and Energy Engineering Beijing University of Technology Beijing 100124 China. School of Engineering China University of Petroleum (Beijing) at Karamay Karamay 834000 China. CNPC Engineering Technology R&D Company Limited Beijing 102206 China.

To address the issue of sealing failure of cement materials commonly used as wellbore plugging agents in CO geological storage, this study proposes a composite wellbore plugging method that combines cement and Sn58Bi alloy. In this method, a composite sealing structure of "cement-Sn58Bi alloy-cement" is constructed within the wellbore. To evaluate the performance of this method, a series of pressure-bearing and gas-tightness experimental devices were designed, and experiments were conducted to assess the pressure-bearing capacity and gas sealing performance of the composite plugs. Additionally, optical microscopy was employed to observe and analyze the microstructure of the plugs. The effects of alloy proportion and temperature on the sealing performance of the composite plugs were systematically investigated. The experimental results indicate that both the pressure-bearing capacity and gas-tightness performance of the plugs are influenced by the alloy content and ambient temperature. Specifically, when the temperature increased from 30 °C to 60 °C, the pressure-bearing capacity decreased by an average of 28.3%; when further increased from 60 °C to 90 °C, it decreased by an average of 21.1%. In contrast, the gas-tightness performance exhibited an opposite trend, with the breakthrough pressure increasing by an average of 25.7% and 22.0%, respectively, over the same temperature intervals. Moreover, increasing the alloy proportion in the composite plugs enhanced both their pressure-bearing and gas-tightness performances. This study provides theoretical support for the application of composite plugs in CO geological storage.

关键词： CCUS Sn58Bi alloy composite plugging sealing performance

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Controllable Synthetic Carbon dots: A Promising Method for reducing Injection Pressure in Matrix by regulating Oil/Water/rock Interface Properties

SSRN

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SSrN 2023年

作者： Cao, Mengjiao Li, Yuan Song, Xuguang Chen, Yesheng Sun, Linghui Shi, Xin dai, Caili Yuan, Bin School of Petroleum Engineering China University of Petroleum（East China） Qingdao266580 China Sinopec Research Institute of Petroleum Engineering Fracturing & Acidizing and Natural Gas Production Research Institute Dongying257000 China Department of Chemical and Materials Engineering University of Alberta EdmontonABT6G 1H9 Canada CNPC Engineering Technology R&D Company Limited Beijing Petroleum Machinery Company China China Academy of Science Institute of Porous Flow & Fluid Mechanics Beijing100083 China Sinopec Northwest China Petroleum Bureau Urumqi830011 China

Effective development of unconventional resources is impeded by water flooding-related challenges, such as high pressure and under-injection, which hinder the replenishment of formation energy. Nanofluids have shown promise in reducing injection pressure, but traditional nanoparticles (NPs) face limitations in unconventional reservoirs due to their unsuitable size for micro-nano pores and aggregation tendencies. In this paper, novel carbon dots (Cds) with a simple, environmentally benign, and controllable synthetic approach have been developed, and their pressure-reduction performance and mechanism have been systematically explored. The particle size of the Cds could be tailored by a well-timely quenching reaction. Cds nanofluid demonstrated superior stability, dispersibility, and temperature/salinity resistance. In addition, Cds can regulate interfacial properties, including oil/rock and oil/water interfaces. It was found that Cds could be partially absorbed onto pore walls, reducing oil adhesion sites by 39%, altering wettability from oil-wet to neutral, and reducing rock surface roughness by 29.25%. Furthermore, Cds were rapidly adsorbed onto the remaining oil film in the pore space, reducing interfacial tension while solidifying the oil surfaces, increasing shear force around the oil surface by 1.7 times during subsequent water scouring, which makes the oil film break up more readily and remain smaller in size to migrate in the channeling. The modulation of the interface properties by Cds improved the stripping efficiency of the attached oil film and ameliorated the homogeneity and smoothness of flow channel, resulting in a significant reduction in injection pressure. Core displacement tests showed that a 0.1wt% Cds nanofluid could achieve a pressure reduction rate of 35%. The developed Cds nanofluid represents a promising solution for reducing injection pressure and improving oil recovery in unconventional reservoirs. © 2023, The Authors. All rights reserved.

关键词： Particle size

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