【作者】 邹龙庆；

【导师】 姚熊亮；

【作者基本信息】 哈尔滨工程大学 ， 船舶与海洋结构物设计制造， 2006， 博士

【摘要】 井架是石油钻机起升设备的重要组成部分之一，在油田钻井中，用于安放天车，悬挂游车、大钩及专用工具，起下钻、下套管等。作为承载构件的钻机井架，其工作环境远比一般的钢结构物恶劣。井架结构要承受提放钻具的大钩载荷、风激励产生的风载荷以及钻机振动时产生的振动载荷等动载荷作用。目前，采用等效静力法研究井架结构，仅仅能满足井架设计阶段的基本要求，对井架在动载下的振动响应没有进行深入研究。特殊情况下的纵向冲击响应，正常工作阶段受周期性持续载荷作用的响应，以及在风载荷作用下的风致振动问题已经受到关注。在动载下对井架进行动态响应分析，能够更有效地减少或避免油田生产中发生的井架动力失效或被风刮倒而造成的安全事故。因此，开展动载荷作用下的钻机井架动态响应研究，对井架结构设计和油田安全生产有着重要指导意义。本文主要以前开口钻机井架为对象，根据弹性体理论和模型等效原则建立了用于动态特性分析的井架系统动力学模型，并根据井架结构特点和工作实际将其划分为特殊工作状态和正常工作状态两种工况，通过概率统计方法，以大钩载荷为统计变量获得井架竖向载荷概率模型，继而采用国内惯用的编谱原则，编制符合实际的瞬态冲击载荷历程和周期性试验用程序载荷谱，对钻机井架进行了瞬态动力学分析与动态响应计算，得到了井架在动载何作用下的变形和应力变化，以及井架顶部、二层台和人字架等主要部位在不同方向的时间响应变化规律和振动特性。采用ANSYS软件对井架进行了模态分析，获得了前10阶固有频率和振型，并在此基础上进行响应谱分析，得到井架的频率响应特性。运用空气动学原理，研究了大庆油田的陆地风场特性，进行了井架结构风载荷谱分析。现场采集大庆地区从1960～2003年间44年的年最大风速气象资料，建立了极值Ⅰ型概率分析数学模型，对钻机井架的设计风速进行概率统计分析。根据油田生产实际，建立了9种模拟井架结构力学行为的载荷工况，运用结构随机振动理论计算了四段井架结构的风振系数和等效脉动风载荷。用能量法系统分析了各种脉动风速谱和风力谱的基本规律，给出了基于三角级数叠加谐波合成法的脉动风模拟方法，并采用Matlab6.5软件给出了风载荷的数值模拟结果。探讨了钻机井架风致振动的安全评价方法。通过分析风载荷与井架结构的相互作用和破坏形式，运用安全度和疲劳验算方法，评价了井架结构风振安全性能。用风玫瑰图描述了大庆地区冬季、夏季、全年的主导风向，建立了油田安全生产中的井位安装方位图。安全评价结果表明，井架结构在飓风情况下，井架顶部已经超过安全度控制极限，可能出现第一风向倾倒，但不会发生疲劳破坏。分别研究了周期钩载与风载荷以及瞬时冲击钩载与风载荷两种耦合工况下井架结构的动态响应问题。结果表明，两种载荷的耦合作用对井架结构的动态响应有一定的影响。首次提出了在井架结构中安装阻尼减振器，研究计算了减振后井架的动态响应。结果表明，井架立柱轴向振动大幅减弱，能有效抑制井架前倾弯曲变形，还可以“推迟”井架振动最大幅值出现的时刻，加快振动衰减，减少剩余振动产生的危害。更多还原

【Abstract】 Oil derricks is one of the most important rig equipment in hoist system. In oilfield drilling, people can install crown block and hang tackle, hoisting hook and special tools on it, and also complete manipulations such as making a trip, casing running and so on. Rig derrick, being main part to bear load, is always working at worse circumstances than other common steal structure. Derrick structure must undergo hook load in tripping, wind load outdoors and vibration load when drilling machine is running. At present, it can only satisfy the base requirement in stage of design to research derrick structure by static equivalent method, nothing done further when rig derrick is undergoing the dynamical load. It has drawn attention that response researches are on longitudinal impaction in special circumstance, periodic loads in work phases and wind vibration under wind load. It can effectively decrease or avoid the dynamic invalidation of derrick structure and the phenomenon of derrick collapse resulting from wind to produce accidence. So it is important and can give constructive guidance to structure design of derrick and safety production in oil field.This thesis takes the front-open type derrick as the object to build the dynamic model of drilling rig derrick by the theory of elastic body and principle of model equivalent, and classify two operating modes, especial and normal modes, by the structure character and work practice of derrick. At the same time, based on probability statistics and probability model of vertical loads, the thesis establishes the load spectrum in periodic experiment and transient course with time impact, then implements the transient analysis and dynamic response calculation. It draws some conclusions including the changes of deformation and stress of derrick structure under dynamic loads, and the vibration rules and characteristic of time responses in different orientation in the main parts such as top, racking platform and propeller strut of drilling rig derrick.This thesis completes the mode analysis of rig derrick by finite elementsoftware——ANSYS, getting the free frequencies of preceding 10 steps andvibration modes. Based all above, it completes the response spectrum analysis, getting the characteristic between frequencies and responses of the derrick system. The principle of the aerodynamics is used to study the characteristic of land wind field of the Daqing Oil Field. Then, the thesis completes the theory analysis of wind load spectrum of oil rig derrick. By gathering the meteorological data of annual maximum wind speed for 44 years from 1960 to 2003 in Daqing Oil Field, it founds the mathematics model of probability analysis, Extreme Value I, to achieve the wind probability analysis of rig derrick under design speed. According to the production reality of oilfield, 9 kinds of load situations are set up to simulate the mechanics action. After that, it calculates the wind vibration coefficients and pulsating equivalent wind-load at four parts of derrick by theory of structure random vibration. Using the energy method, it analyzes various types of pulsating wind spectrum, and puts forward the simulation method of pulsating wind based of synthetic method of triangular progression superposing harmonic. Furthermore, it gives the numerical simulation result of the wind loads by software Matlab6.5.In the thesis, the safety evaluation method of wind vibration of the oil rig derrick has been further discussed. It valuates the safety characteristic of the rig derrick under wind vibration by analysis of interaction between wind load and derrick and destroyed forms about derrick structure, using the way of safety degree and fatigue computations. Describing the leading wind direction in winter, summer and the whole year in Daqing with the wind rose picture, it builds the location orientation diagram of the well for oil field. It concludes that the top of derrick structure in case of hurricane has already exceeded the control limit of safety degree, which is likely to collapse at first wind direction, but can’t been destroyed by fatigue.Respectively, the dynamic response of derrick has been researched in two different situations which are the coupling of periodic hookload and wind load and that of impact hookload and wind load. All calculations conclude that two load couplings can affect the dynamic response of rig derrick correspondingly.更多还原