Enhancement of technology and techniques for drilling deep directed oil and gas bore hole is one of the most important problems of the current petroleum industry.Not infrequently, the drilling of these bore holes is a...Enhancement of technology and techniques for drilling deep directed oil and gas bore hole is one of the most important problems of the current petroleum industry.Not infrequently, the drilling of these bore holes is attended by occurrence of extraordinary situations associated with technical accidents. Among these is the Eulerian loss of stability of a drill string in the channel of a curvilinear bore hole. Methods of computer simulation should play a dominant role in prediction of these states. In this paper, a new statement of the problem of critical buckling of the drill strings in 3D curvilinear bore holes is proposed. It is based on combined use of the theory of curvilinear elastic rods, Eulerian theory of stability, theory of channel surfaces, and methods of classical mechanics of systems with nonlinear constraints. It is noted that the stated problem is singularly perturbed and its solutions have the shapes of localized harmonic wavelets. The calculation results showed that the friction effects lead to essential redistribution of internal axial forces, as well as changing the eigenmode shapes and sites of their localization. These features make the buckling phenomena less predictable and raise the role of computer simulation of these effects.展开更多
针对塔里木盆地台盆区超深小井眼定向钻井机械钻速低、钻头使用寿命短、常规螺杆钻具脱胶脱扣、钻井液稳定性差和产层喷漏同存等难题,研究形成了塔里木盆地超深小井眼定向钻井提速提效关键技术。以标准行程钻速和钻头进尺为指标,采用统...针对塔里木盆地台盆区超深小井眼定向钻井机械钻速低、钻头使用寿命短、常规螺杆钻具脱胶脱扣、钻井液稳定性差和产层喷漏同存等难题,研究形成了塔里木盆地超深小井眼定向钻井提速提效关键技术。以标准行程钻速和钻头进尺为指标,采用统计分析法优选了适用于目的层的ϕ149.2 mm/ϕ165.1 mm KS1352DGRX型钻头和ϕ120.7 mm KDM1062TR型钻头;对比国内外抗高温螺杆现状,确定了井底温度低于180℃时推荐使用国产抗高温螺杆,高于180℃时推荐使用全金属螺杆或进口耐高温螺杆;采用理论分析结合数值模拟的方法,优化设计了小尺寸降摩减阻工具,并优化了其安放位置;优选抗盐高温高压降滤失剂和抑制剂,研选除氧剂等,制定合理pH值调控和钙离子补充措施,形成了抗温200℃钻井液;分析了顺北油气田产层钻进喷漏同层的特点,确定了“降密度+井口控压+优化排量”的井控基本原则。塔里木盆地5口井应用了超深小井眼定向钻井提速提效关键技术,小井眼段平均机械钻速提高了113.24%,平均井径扩大率5.57%,平均钻井周期缩短了35.03%,均未发生井下故障和复杂情况。超深小井眼定向钻井提速提效技术为塔里木盆地勘探开发提供了技术支撑。展开更多
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
An incremental updated Lagrangian elasto-plastic finite element method(FEM) was employed to analyze the hole-flanging with the ironing of circulate plates using a pre-determined smaller hole at the center of the two-p...An incremental updated Lagrangian elasto-plastic finite element method(FEM) was employed to analyze the hole-flanging with the ironing of circulate plates using a pre-determined smaller hole at the center of the two-ply sheet metals. An extended rmin technique was employed such that each incremental step size can be determined not only by the yielding of an element Gaussian point, but also by the change under the boundary conditions of penetration, separation, and the alternation of the sliding-sticking state of friction along the tool-sheet interface. Two-ply sheet metals are generally composed of metals that have different mechanical properties. Thus, the forming process of these materials is complicated. A number of experiments and simulations were performed using a conical punch with a cone angle of 45°. The experimental results were compared with FEM-simulated results. It is found that using the elasto-plastic FEM can effectively predict the generation process of the deformed shape until unloading. The calculated sheet geometries and the relationship between punch load and punch travel are in good agreement with the experimental data.展开更多
文摘Enhancement of technology and techniques for drilling deep directed oil and gas bore hole is one of the most important problems of the current petroleum industry.Not infrequently, the drilling of these bore holes is attended by occurrence of extraordinary situations associated with technical accidents. Among these is the Eulerian loss of stability of a drill string in the channel of a curvilinear bore hole. Methods of computer simulation should play a dominant role in prediction of these states. In this paper, a new statement of the problem of critical buckling of the drill strings in 3D curvilinear bore holes is proposed. It is based on combined use of the theory of curvilinear elastic rods, Eulerian theory of stability, theory of channel surfaces, and methods of classical mechanics of systems with nonlinear constraints. It is noted that the stated problem is singularly perturbed and its solutions have the shapes of localized harmonic wavelets. The calculation results showed that the friction effects lead to essential redistribution of internal axial forces, as well as changing the eigenmode shapes and sites of their localization. These features make the buckling phenomena less predictable and raise the role of computer simulation of these effects.
文摘针对塔里木盆地台盆区超深小井眼定向钻井机械钻速低、钻头使用寿命短、常规螺杆钻具脱胶脱扣、钻井液稳定性差和产层喷漏同存等难题,研究形成了塔里木盆地超深小井眼定向钻井提速提效关键技术。以标准行程钻速和钻头进尺为指标,采用统计分析法优选了适用于目的层的ϕ149.2 mm/ϕ165.1 mm KS1352DGRX型钻头和ϕ120.7 mm KDM1062TR型钻头;对比国内外抗高温螺杆现状,确定了井底温度低于180℃时推荐使用国产抗高温螺杆,高于180℃时推荐使用全金属螺杆或进口耐高温螺杆;采用理论分析结合数值模拟的方法,优化设计了小尺寸降摩减阻工具,并优化了其安放位置;优选抗盐高温高压降滤失剂和抑制剂,研选除氧剂等,制定合理pH值调控和钙离子补充措施,形成了抗温200℃钻井液;分析了顺北油气田产层钻进喷漏同层的特点,确定了“降密度+井口控压+优化排量”的井控基本原则。塔里木盆地5口井应用了超深小井眼定向钻井提速提效关键技术,小井眼段平均机械钻速提高了113.24%,平均井径扩大率5.57%,平均钻井周期缩短了35.03%,均未发生井下故障和复杂情况。超深小井眼定向钻井提速提效技术为塔里木盆地勘探开发提供了技术支撑。
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.
文摘An incremental updated Lagrangian elasto-plastic finite element method(FEM) was employed to analyze the hole-flanging with the ironing of circulate plates using a pre-determined smaller hole at the center of the two-ply sheet metals. An extended rmin technique was employed such that each incremental step size can be determined not only by the yielding of an element Gaussian point, but also by the change under the boundary conditions of penetration, separation, and the alternation of the sliding-sticking state of friction along the tool-sheet interface. Two-ply sheet metals are generally composed of metals that have different mechanical properties. Thus, the forming process of these materials is complicated. A number of experiments and simulations were performed using a conical punch with a cone angle of 45°. The experimental results were compared with FEM-simulated results. It is found that using the elasto-plastic FEM can effectively predict the generation process of the deformed shape until unloading. The calculated sheet geometries and the relationship between punch load and punch travel are in good agreement with the experimental data.
