Down-hole tubular string buckling is the most classic and complex part of tubular string mechanics in well engineering. Studies of down-hole tubular string buckling not only have theoretical significance in revealing ...Down-hole tubular string buckling is the most classic and complex part of tubular string mechanics in well engineering. Studies of down-hole tubular string buckling not only have theoretical significance in revealing the buckling mechanism but also have prominent practical value in design and control of tubular strings. In this review, the basic principles and applicable scope of three classic research methods （the beam-column model, buck- ling differential equation, and energy method） are intro- duced. The critical buckling loads and the post-buckling behavior under different buckling modes in vertical, inclined, horizontal, and curved wellbores from different researchers are presented and compared. The current understanding of the effects of torque, boundary condi- tions, friction force, and connectors on down-hole tubular string buckling is illustrated. Meanwhile, some unsolved problems and controversial conclusions are discussed. Future research should be focused on sophisticated description of buckling behavior and the coupling effect of multiple factors. In addition, active control of down-hole tubular string buckling behavior needs some attention urgently.展开更多
With permanent down-hole gauges （PDGs） widely installed in oilfields around the world in recent years, a continuous stream of transient pressure data in real time is now available, which motivates a new round of res...With permanent down-hole gauges （PDGs） widely installed in oilfields around the world in recent years, a continuous stream of transient pressure data in real time is now available, which motivates a new round of research interests in further developing pressure transient processing and analysis techniques. Transient pressure measurements from PDG are characterized by long term and high volume data. These data are recorded under unconstrained circumstances, so effects due to noise, rate fluctuation and interference from other wells cannot be avoided. These effects make the measured pressure trends decline or rise and then obscure or distort the actual flow behavior, which makes subsequent analysis difficult. In this paper, the problems encountered in analysis of PDG transient pressure are investigated. A newly developed workflow for processing and analyzing PDG transient pressure data is proposed. Numerical well testing synthetic studies are performed to demonstrate these procedures. The results prove that this new technique works well and the potential for practical application looks very promising.展开更多
In a deep well,under high pressure and temperature,the force,deformation,and movement of the downhole string are very complicated. In this paper,based on the analysis of the working environment and load properties of ...In a deep well,under high pressure and temperature,the force,deformation,and movement of the downhole string are very complicated. In this paper,based on the analysis of the working environment and load properties of the down-hole string in deep wells,the factors of high temperature,high pressure,and the complex structure of wells have been taken into consideration. The loads of the down-hole string,stability,back buckle configuration,dynamic characteristics,mechanical strength,and deformation have been systematically studied. On this basis,mechanical models of a down-hole string under different conditions have been established and software for aiding analysis has been developed. By using this software,deep well strings under different construction parameters can be simulated and analyzed,providing a theoretical basis and method for down-hole string assembly,as well as string down-hole construction and operation.展开更多
在电源供电系统中,浪涌的产生会对电子元器件造成不可逆的损害。电源开断瞬息产生的强力尖峰脉冲会对集成电路进行浪涌冲击。本文就浪涌电压冲击对电路造成的损害,通过理论和实验分析了TVS实际选型问题,并对比分析了TVS电路和电容电路...在电源供电系统中,浪涌的产生会对电子元器件造成不可逆的损害。电源开断瞬息产生的强力尖峰脉冲会对集成电路进行浪涌冲击。本文就浪涌电压冲击对电路造成的损害,通过理论和实验分析了TVS实际选型问题,并对比分析了TVS电路和电容电路对浪涌冲击带来的失效问题的抑制能力,在此基础上提出了基于TVS和电容的浪涌保护电路方案。In the power supply system, the generation of surge will cause irreversible damage to electronic components. The strong spike pulse produced by the instant of power supply disconnection will cause surge impact to the integrated circuit. In this paper, based on the damage caused by surge voltage shock to the circuit, the actual TVS selection problem is analyzed through theory and experiment, and the suppression ability of TVS and capacitor circuit to the failure problem caused by surge shock is compared and analyzed. On this basis, the surge protection circuit scheme based on TVS and capacitor is proposed.展开更多
基金the financial support from the Natural Science Foundation of China (NSFC,51221003,U1262201)the Science Foundation of China University of Petroleum,Beijing (No.00000)supported by other projects (Grant Numbers:2014A-4214,2013AA064803,2011ZX05009-005)
文摘Down-hole tubular string buckling is the most classic and complex part of tubular string mechanics in well engineering. Studies of down-hole tubular string buckling not only have theoretical significance in revealing the buckling mechanism but also have prominent practical value in design and control of tubular strings. In this review, the basic principles and applicable scope of three classic research methods （the beam-column model, buck- ling differential equation, and energy method） are intro- duced. The critical buckling loads and the post-buckling behavior under different buckling modes in vertical, inclined, horizontal, and curved wellbores from different researchers are presented and compared. The current understanding of the effects of torque, boundary condi- tions, friction force, and connectors on down-hole tubular string buckling is illustrated. Meanwhile, some unsolved problems and controversial conclusions are discussed. Future research should be focused on sophisticated description of buckling behavior and the coupling effect of multiple factors. In addition, active control of down-hole tubular string buckling behavior needs some attention urgently.
基金Science Foundation of China University of Petroleum, Beijing (No.YJRC-2011-02)for the financial support during this research
文摘With permanent down-hole gauges （PDGs） widely installed in oilfields around the world in recent years, a continuous stream of transient pressure data in real time is now available, which motivates a new round of research interests in further developing pressure transient processing and analysis techniques. Transient pressure measurements from PDG are characterized by long term and high volume data. These data are recorded under unconstrained circumstances, so effects due to noise, rate fluctuation and interference from other wells cannot be avoided. These effects make the measured pressure trends decline or rise and then obscure or distort the actual flow behavior, which makes subsequent analysis difficult. In this paper, the problems encountered in analysis of PDG transient pressure are investigated. A newly developed workflow for processing and analyzing PDG transient pressure data is proposed. Numerical well testing synthetic studies are performed to demonstrate these procedures. The results prove that this new technique works well and the potential for practical application looks very promising.
基金The National Natural Science Foundation of China (Nos. 50874096 and 50474040)
文摘In a deep well,under high pressure and temperature,the force,deformation,and movement of the downhole string are very complicated. In this paper,based on the analysis of the working environment and load properties of the down-hole string in deep wells,the factors of high temperature,high pressure,and the complex structure of wells have been taken into consideration. The loads of the down-hole string,stability,back buckle configuration,dynamic characteristics,mechanical strength,and deformation have been systematically studied. On this basis,mechanical models of a down-hole string under different conditions have been established and software for aiding analysis has been developed. By using this software,deep well strings under different construction parameters can be simulated and analyzed,providing a theoretical basis and method for down-hole string assembly,as well as string down-hole construction and operation.
文摘在电源供电系统中,浪涌的产生会对电子元器件造成不可逆的损害。电源开断瞬息产生的强力尖峰脉冲会对集成电路进行浪涌冲击。本文就浪涌电压冲击对电路造成的损害,通过理论和实验分析了TVS实际选型问题,并对比分析了TVS电路和电容电路对浪涌冲击带来的失效问题的抑制能力,在此基础上提出了基于TVS和电容的浪涌保护电路方案。In the power supply system, the generation of surge will cause irreversible damage to electronic components. The strong spike pulse produced by the instant of power supply disconnection will cause surge impact to the integrated circuit. In this paper, based on the damage caused by surge voltage shock to the circuit, the actual TVS selection problem is analyzed through theory and experiment, and the suppression ability of TVS and capacitor circuit to the failure problem caused by surge shock is compared and analyzed. On this basis, the surge protection circuit scheme based on TVS and capacitor is proposed.
