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Analysis of mechanical strengths of extreme line casing joint considering geometric, material, and contact nonlinearities

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Petroleum Science 2024年第3期21卷 1992-2004页

作者： Ji-Yun Zhang Chi Peng Jian-Hong Fu Quan Cao Yu Su Jian-Yun Pang Zi-Qiang Yu Petroleum engineering School Southwest Petroleum University engineering Technology Research Institute of CNPC Southwest Oil and Gas Field company

To address the challenges associated with difficult casing running, limited annular space, and poor cementing quality in the completion of ultra-deep wells, the extreme line casing offers an effective solution over conventional casings. However, due to its smaller size, the joint strength of extreme line casing is reduced, which may cause failure when running in the hole. To address this issue, this study focuses on the CST-ZT Φ139.7 mm × 7.72 mm extreme line casing and employs the elastic-plastic mechanics to establish a comprehensive analysis of the casing joint, taking into account the influence of geometric and material nonlinearities. A finite element model is developed to analyze the forces and deformations of the extreme line casing joint under axial tension and external collapse load. The model investigates the stress distribution of each thread tooth subjected to various tensile forces and external pressures. Additionally, the tensile strength and crushing strength of the extreme line casing joint are determined through both analytical and experimental approaches. The findings reveal that, under axial tensile load, the bearing surface of each thread tooth experiences uneven stress, with relatively high equivalent stress at the root of each thread tooth. The end thread teeth are valuable spots for failure. It is observed that the critical fracture axial load of thread decreases linearly with the increase of thread tooth sequence. Under external pressure, the circumferential stress is highest at the small end of the external thread, leading to yield deformation. The tensile strength of the joint obtained from the finite element model exhibits a relative error of less than 7% compared to the analytical and experimental values,proving the reliability of the finite element model. The tensile strength of the joint is 3091.9 k N.Moreover, in terms of anti-collapse capability, the joints demonstrate higher resistance to collapse compared to the casing body, which is consistent with the test results where the pip

关键词： Extreme line casing Elastic-plastic mechanics Finite element analysis Tensile strength Collapse strength

CFD simulation and optimization of an industrial cement gas-solid air classifier

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Particuology 2024年第6期89卷 172-184页

作者： Mohamadreza Esmaeilpour Ali Mohebbi Vahab Ghalandari Department of Chemical engineering Faculty of EngineeringShahid Bahonar University of KermanKermanIran Kerman Momtazan Cement company KermanIran

An air classifier is one of the main and effective devices in cement industry.In this study,a three-dimensional,steady and two-phase(solid-gas)computational fluid dynamics(CFD)simulation was performed to optimize the performance of this device in the Kerman Momtazan cement plant,Iran.After the validation of CFD results,the air flow field and air path lines between fixed blades were checked carefully and the non-uniformity in velocity distribution and the formation of vortex flows between the blades close to particle inlets were observed.The study tried to improve the device efficiency by changing the method of entering particles into the device,resulting in a reduction in air classifier electrical energy consumption(from 41 to 35(kW h)/t)and an increase in production rate(from 203 to 214 t/h).Additionally,the study investigated the effects of other modifiable operating conditions like rotary cage rotation speed,pressure difference,and inlet air temperature on the particle size distribution and classifier efficiency.The results showed that increasing the cage rotation speed decreased the product rate and the product particles mean diameter while increasing pressure difference or increasing temperature increased the product rate and the product particles mean diameter.It was concluded that these modifiable operating conditions can significantly affect the performance of the air classifier in the cement industry.

关键词： Cement air classifier Computational fluid dynamics Gas-solid two-phase flow Optimization Eulerian-Lagrangian method Efficiency

A review of reservoir damage during hydraulic fracturing of deep and ultra-deep reservoirs

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Petroleum Science 2024年第1期21卷 384-409页

作者： Kun Zhang Xiong-Fei Liu Dao-Bing Wang Bo Zheng Tun-Hao Chen Qing Wang Hao Bai Er-Dong Yao Fu-Jian Zhou National Key Laboratory of Petroleum Resources and engineering China University of Petroleum-BeijingBeijing102249China School of Mechanical engineering Beijing Institute of Petrochemical TechnologyBeijing102617China Tuha Downhole Operation company CNPC Xibu Drilling Engineering Company LimitedShanshan838200XinjiangChina

Deep and ultra-deep reservoirs have gradually become the primary focus of hydrocarbon exploration as a result of a series of significant discoveries in deep hydrocarbon exploration worldwide.These reservoirs present unique challenges due to their deep burial depth(4500-8882 m),low matrix permeability,complex crustal stress conditions,high temperature and pressure(HTHP,150-200℃,105-155 MPa),coupled with high salinity of formation water.Consequently,the costs associated with their exploitation and development are exceptionally high.In deep and ultra-deep reservoirs,hydraulic fracturing is commonly used to achieve high and stable production.During hydraulic fracturing,a substantial volume of fluid is injected into the reservoir.However,statistical analysis reveals that the flowback rate is typically less than 30%,leaving the majority of the fluid trapped within the reservoir.Therefore,hydraulic fracturing in deep reservoirs not only enhances the reservoir permeability by creating artificial fractures but also damages reservoirs due to the fracturing fluids involved.The challenging“three-high”environment of a deep reservoir,characterized by high temperature,high pressure,and high salinity,exacerbates conventional forms of damage,including water sensitivity,retention of fracturing fluids,rock creep,and proppant breakage.In addition,specific damage mechanisms come into play,such as fracturing fluid decomposition at elevated temperatures and proppant diagenetic reactions at HTHP conditions.Presently,the foremost concern in deep oil and gas development lies in effectively assessing the damage inflicted on these reservoirs by hydraulic fracturing,comprehending the underlying mechanisms,and selecting appropriate solutions.It's noteworthy that the majority of existing studies on reservoir damage primarily focus on conventional reservoirs,with limited attention given to deep reservoirs and a lack of systematic summaries.In light of this,our approach entails initially summarizing the current knowledge pertaining to the types

关键词： Artificial fracture Deep and ultra-deep reservoir Fracture conductivity Fracturing fluid Hydraulic fracturing Reservoir damage

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Integrated Frequency-constrained Scheduling Considering Coordination of Frequency Regulation Capabilities from Multi-source Converters

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 261-274页

作者： Jiaming Li Ying Qiao Zongxiang Lu Wei Ma Xin Cao Rongfu sun the Department of Electrical engineering Tsinghua UniversityBeijing 100084China the China suntien Green Energy Limited company Shijiazhuang 050011China the State Grid Jibei Electric Power company Beijing 100054China

As the proportion of renewable energy(RE)increases,the inertia and the primary frequency regulation(FR)capability of the power system decrease.Thus,ensuring frequency security in the scheduling model has become a new technical requirement in power systems with a high share of RE.Due to a shortage of conventional synchronous generators,the frequency support of multi-source converters has become an indispensable part of the system frequency resources,especially variable-speed wind turbine generation(WTG)and battery energy storage(BES).Quantitative expression of the FR capability of multi-source converters is necessary to construct frequency-constrained scheduling model.However,the frequency support performance of these converter-interfaced devices is related to their working states,operation modes,and parameters,and the complex coupling of these factors has not been fully exploited in existing models.In this study,we propose an integrated frequency-constrained scheduling model considering the coordination of FR capabilities from multi-source converters.Switchable FR control strategies and variable FR parameters for WTG with or without reserved power are modeled,and multi-target allocation of BES capacity between tracking dispatch instruction and emergency FR is analyzed.Then,the variable FR capabilities of WTG and BES are embedded into the integrated frequency-constrained scheduling model.The nonlinear constraints for frequency security are precisely linearized through an improved iteration-based strategy.The effectiveness of the proposed model is verified in a modified IEEE 24-bus standard system.The results suggest that the coordinated participation of BES and WTG in FR can effectively reduce the cost of the scheduling model while meeting frequency security constraints.

关键词： Battery energy storage(BES) wind turbine generation(WTG) frequency regulation(FR) frequency security power system scheduling

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Effect of fracture fluid flowback on shale microfractures using CT scanning

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Journal of Rock Mechanics and Geotechnical engineering 2024年第2期16卷 426-436页

作者： Jiale He Zhihong Zhao Yiran Geng Yuping Chen Jianchun Guo Cong Lu Shouyi Wang Xueliang Han Jun Zhang State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500China Key Laboratory of Thermo-Fluid Science and engineering of Ministry of Education School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an710049China Drilling Test engineering Department of Longdong Oil and Gas Development company Changqing OilfieldPetroChina Company LimitedQingyang745000China Tight Oil and Gas Exploration and Development Project Department PetroChina Southwest Oil and Gas Field CompanyChengdu610056China No.11 Oil Production Plant Changqing Oilfield CompanyPetroChina Company LimitedQingyang745000China

The field data of shale fracturing demonstrate that the flowback performance of fracturing fluid is different from that of conventional reservoirs,where the flowback rate of shale fracturing fluid is lower than that of conventional reservoirs.At the early stage of flowback,there is no single-phase flow of the liquid phase in shale,but rather a gas-water two-phase flow,such that the single-phase flow model for tight oil and gas reservoirs is not applicable.In this study,pores and microfractures are extracted based on the experimental results of computed tomography(CT)scanning,and a spatial model of microfractures is established.Then,the influence of rough microfracture surfaces on the flow is corrected using the modified cubic law,which was modified by introducing the average deviation of the microfracture height as a roughness factor to consider the influence of microfracture surface roughness.The flow in the fracture network is simulated using the modified cubic law and the lattice Boltzmann method(LBM).The results obtained demonstrate that most of the fracturing fluid is retained in the shale microfractures,which explains the low fracturing fluid flowback rate in shale hydraulic fracturing.

关键词： Shale Flowback of fracturing fluid Microfracture Lattice Boltzmann method(LBM)

High-efficiency ultrasonic assisted drilling of CFRP/Ti stacks under non-separation type and dry conditions

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2024年第4期25卷 275-291页

作者： Enze YING Zehua ZHOU Daxi GENG Zhenyu SHAO Zhefei sun Yihang LIU Lianxing LIU Xinggang JIANG Deyuan ZHANG School of Mechanical engineering and Automation Beihang UniversityBeijing 100191China Beijing Chenjing Electronics company Limited Beijing 100015China Aerospace Times Feihong Technology company Limited Beijing 100094China

In this study,to address the low efficiency for conventional ultrasonic-assisted drlling(UAD)of carbon fiber-reinforced plastic and titanium alloy(CFRP/Ti)stacks,feasibility experiments of non-separation UAD,in which continuous cutting between the tool and the workpiece occurs at a high feed rate,are carried out.The experimental results indicate that,compared to conventional separation UAD,the non-separation UAD effectively reduces the cutting forces by 24.2%and 1.9%for CFRP stage and 22.1%and 2.6%for the Ti stage at the feed rates of 50 and 70μm/r,respectively.Furthermore,the non-separation UAD significantly improves hole quality,including higher hole diameter accuracy,lower hole surface roughness,and less hole damage.In addition,the non-separation UAD can decrease adhesive tool wear.This study demonstrates that,compared to conventional drilling(CD),the non-separation UAD can effectively improve drilling quality and tool life while maintaining high efficiency.

关键词： Carbon fiber-reinforced plastic and titanium alloy(CFRP/Ti)stacks Ultrasonic-assisted drlling(UAD) Cutting force Surface integrity Tool wear

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Acid-rock reaction kinetics in a two-scale model based on reaction order correction

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Petroleum Science 2024年第3期21卷 2089-2101页

作者： Xue-Song Li Ning Qi Ze-Hui Zhang Lian Liu Xia-Qing Li Xu-Hang Su School of Petroleum engineering China University of Petroleum(East China) Key Lab of Unconventional Oil & Gas Development Ministry of Education China University of Petroleum(East China) SINOPEC Northwest Oilfield Branch company Petroleum engineering Technology Research Institute SINOPEC Shengli Oilfield Company

The reaction order plays a crucial role in evaluating the response rate of acid-rock. However, the conventional two-scale model typically assumes that the reaction order is constant as one, which can lead to significant deviations from reality. To address this issue, this study proposes a novel multi-order dynamic model for acid-rock reaction by combining rotating disk experimental data with theoretical derivation.Through numerical simulations, this model allows for the investigation of the impact of acidification conditions on different orders of reaction, thereby providing valuable insights for on-site construction.The analysis reveals that higher response orders require higher optimal acid liquid flow rates, and lower optimal H+diffusion coefficients, and demonstrate no significant correlation with acid concentration.Consequently, it is recommended to increase the displacement and use high-viscosity acid for reservoirs with high calcite content, while reducing the displacement and using low-viscosity acid for reservoirs with high dolomite content.

关键词： Reaction order Two-scale model Wormhole propagation Carbonate rocks Numerical simulation

Distributed Hybrid Model Predictive Secondary Control of DC Microgrids with Random Communication Disorders

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 925-935页

作者： Meysam Yaribeygi Zeinab Karami Qobad Shafiee Hassan Bevrani the Department of Electrical engineering K.N.Toosi University of Technology the Sportradar company the Department of engineering Cybernetics (ITK) Norwegian University of Science and Technology (NTNU) IEEE the Smart/Micro Grids Research Center Department of Electrical Engineering University of Kurdistan

A reliable and robust communication network is essential to exchange information between distributed generators(DGs) and accurately calculate their control actions in microgrids(MGs). However, the integration of the communication network and MGs poses challenges related to the flexibility, availability, and reliability of the system. Furthermore, random communication disorders such as time delays and packet loss can negatively impact the system performance. Therefore, it is essential to design a suitable secondary controller(SC) with a fast dynamic response to restore voltage and appropriate powersharing, while ensuring that the effects of random communication disorders are eliminated. In this regard, an optimal distributed hybrid model predictive secondary control method is presented in this paper. Realistic simulations are carried out in a mixed simulation environment based on MATLAB and OMNET++, by considering IEEE 802.11(Wi Fi) using the recently developed Internet networking(INET) framework. In the implemented application layer, the recovery Unit is responsible for reducing the impact of random communication disorders. The effectiveness and performance of the proposed method in comparison with a conventional model predictive control are verified by simulation results.

关键词： Voltage control Delays Mathematical models Communication networks Power system stability Microgrids Matlab

Numerical Investigation of Combined Production of Natural Gas Hydrate and Conventional Gas

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Fluid Dynamics & Materials Processing 2024年第3期20卷 505-523页

作者： Hongzhi Xu Jian Wang Shuxia Li Fengrui Zhao Chengwen Wang Yang Guo School of Petroleum engineering China University of Petroleum(East China)Qingdao266580China CPOE Research Institute of engineering Technology Tianjin300451China CNPC Offshore engineering company Limited Beijing100028China

Natural gas hydrate(NGH)is generally produced and accumulated together with the underlying conventional gas.Therefore,optimizing the production technology of these two gases should be seen as a relevant way to effectively reduce the exploitation cost of the gas hydrate.In this study,three types of models accounting for the coexistence of these gases are considered.Type A considers the upper hydrate-bearing layer(HBL)adjacent to the lower conventional gas layer(CGL);with the Type B a permeable interlayer exists between the upper HBL and the lower CGL;with the type C there is an impermeable interlayer between the upper HBL and the lower CGL.The production performances associated with the above three models are calculated under different conditions,including only a depressurized HBL(only HBL DP);only a depressurized CGL(only CGL DP);and both the HBL and the CGL being depressurized(HBL+CGL DP).The results show that for Type A and Type B coexistence accumulation models,when only HBL or CGL is depressurized,the gas from the other layer will flow into the production layer due to the pressure difference between the two layers.In the coexistence accumulation model of type C,the cumulative gas production is much lower than that of Type A and Type B,regardless of whether only HBL DP,only CGL DP,or HBL+CGL DP are considered.This indicates that the impermeable interlayer restricts the cross-flow of gas between HBL and CGL.For three different coexistence accumulation models,CGL DP has the largest gas-to-water ratio.

关键词： Natural gas hydrate conventional gas coexistence accumulation depressurization combined production