【作者】 王鹏；

【导师】 闫铁；

【作者基本信息】 东北石油大学 ， 石油与天然气工程， 2014， 博士

【摘要】 海洋深水资源钻探是当前国内外最前沿的钻井技术之一，由于深水钻井平台处于恶劣、复杂的海洋环境中，海上钻井相比陆上钻井具有难度大、要求高等特点。本文研究对象是与海洋深水钻井工程关系密切的部件——深水钻井隔水管。深水钻井隔水管是连接海上平台与海底井口的重要结构，同时也是易受海流破坏的关键部件。随着作业水深增加，隔水管长度加长，隔水管受力状态变得更加复杂，隔水管疲劳破坏问题日渐突出，因此深水钻井隔水管系统力学分析是一项重要的研究课题。本文系统开展了深水钻井隔水管系统动力响应及力学耦合行为的研究工作，主要研究内容包括：(1)深水钻井隔水管横向振动响应分析分析并计算影响隔水管横向振动的各种海洋环境载荷，如海流、波浪、海风、海潮、海冰等，再根据深水隔水管小应变大变形的受力变形特点，应用达朗贝尔原理建立考虑钻柱影响的深水隔水管横向振动数学模型，应用有限差分数值法对深水隔水管的受力变形情况进行数值模拟计算分析。(2)深水钻井隔水管横向振动敏感性因素分析影响深水隔水管动力响应的因素较多，如隔水管顶部张力、海流波浪运动参数、平台漂移、隔水管辅助结构等。本文从隔水管系统的顶部张力变化、隔水管浮力块安放、波浪运动周期，以及钻井平台漂移情况对深水隔水管动力响应进行敏感性因素分析，分析结果可以为隔水管设计提供理论依据。(3)考虑辅助管线影响下深水钻井隔水管涡激效果分析与评价应用数值模拟软件—FLUENT对海洋深水隔水管涡激振动效果进行数值模拟分析，本文主要模拟分析影响涡激效果的两个参数：与海水流向垂直涡激的升力系数和顺流向涡激的阻力系数，以此作为分析及评价隔水管涡激效果。首先，模拟单圆柱绕流下隔水管涡激振动响应，模拟结果与经典实验结果基本一致，验证模拟条件的准确性；然后，重点研究辅助管线如何影响隔水管涡激振动，通过分析涡激振动的升力和阻力系数，并应用频谱响应分析方法对模拟结果进行数据处理，给出了辅助管线影响下隔水管涡脱落定量描述。(4)深水钻井隔水管与顶部张力系统耦合分析深水钻井隔水管除了受钻井船的升沉、横摇、纵摇等因素的影响外，顶部张力系统也会对隔水管顶部产生两个方向的横向激励，即平面内运动和离面运动激励。本文建立了顶部张力系统与隔水管耦合作用模型，该模型考虑了实测海洋浮体的运动响应，为准确分析考虑顶部张力系统作用下深水钻井隔水管运动响应提供一种方法。(5)深水钻井隔水管与内部作业钻柱耦合分析深水钻井隔水管动力响应的另外一个重要影响因素即为钻柱的作用。通常情况下，隔水管内部钻柱有两种运动状态，即绕钻柱自身旋转的自转，以及绕隔水管内壁旋转的公转，同时还伴随着钻柱振动。本文根据力平衡原理，建立一种钻柱与隔水管耦合作用数学模型，给出模型求解方法，并对钻柱的影响效果进行评价与分析。(6)考虑应力比条件下深水钻井隔水管疲劳寿命分析深水隔水管在复杂海洋环境中受交变应力载荷作用，其使用的安全性十分重要。准确预测分析隔水管的应力状态及疲劳寿命显得十分必要，本文应用断裂力学理论中带裂纹结构疲劳寿命预测模型对隔水管在交变应力载荷作用下疲劳寿命进行模拟分析，该方法为复杂应力状态隔水管使用寿命提供理论分析方法。更多还原

【Abstract】 Deep water resources drilling is one of the most advanced technologies home and abroad.The deepwater drilling platform is always in the severe and complicated ocean environment.The research object in this article is a component which is closely related to offshore drilling—deepwater riser. Deepwater riser is an important component that connects offshore drillingplatform and subsea wellhead. Risers are also susceptible to sea current. With increasing lengthof riser and operation depth subsea, the stress state of riser is more and more complicated.Therefore, research on mechanical analysis of deepwater riser system is a vital topic. The mainresearch progresses are listed as follows:(1) Deep water drilling riser transverse vibratory response analysisFirst, environmental loads such as sea wind, sea tide, current, wave force which influenceriser transverse vibration are calculated and analyzed. After that, according to the character ofdeformation of great deformation by small strain, deep water riser transverse vibrationdifferential equation considering offshore platform and internal operation drill strings byd’Alembert principle is established, and the deformation of deep water riser sample analysis canbe achieved by finite difference numerical method.(2) Deep water drilling riser vibration sensitivity factors analysisThe deep water riser dynamic response influencing factors are a lot, such as top tension ofriser, ocean wave force, sea current motion parameters, influence of the platform motion, riserstructure. In this article, change of riser top tension, settle of riser buoyancy module, period ofwave motion and drift of drilling platform sensitivity factors are analyzed, and the result canprovide theoretical basis of riser design.(3) Deep water riser vortex–induced vibration effect analysis considering effect ofauxiliary pipeline evaluation and analysis.Deep water riser vortex–induced vibration effect has been numerical modeled by largescaled software—Fluent.In this paper, there are two parameters, which affect the vortex-induced result: lift coefficient whose flow direction perpendicular to ocean current and vortex-induced drag coefficient, which flows downstream. Evaluation of the riser vortex-induced resultis based on these two parameters.First, riser vortex–induced vibration response under singlecylinder circular flow condition is simulated, and the result is in agreement with classicexperiment result, therefore, accuracy of simulated condition can be validated; After that, howthe auxiliary pipeline affects the vortex–induced vibration of the riser is focused on.Quantitative description of pull off after the vortex with effect of auxiliary pipeline can be givenby analysis of lift coefficient and drag coefficient and data processing of simulation result withspectral response analysis.(4) Coupled analysis between deep water riser and top tension systemMany factors affects deep water riser dynamic response such as drilling ship heave, roll,pitch. Meanwhile, the top tension system causes transverse excitations in two directions, which include in plane and out of plane. In this paper, coupling model is established between riser andtop tension system, which considering the float motion response in ocean currents, and itprovides a method to analysze riser dynamic response under the condition of the top tensionsystem.(5) Coupled analysis between deep water riser and internal drillstringAnother important factor is the influence of drill string in the riser dynamic response.Typically, internal drill string in the riser has two kinds of motion state, namely autorotation ofthe drillstring and revolution in the riser, and it also accompanied by the drill string vibration.According to the principle of force, coupling model is established between riser and drill string,it also gives the solution model, and the effect of drill string has been analyzed.(6) Fatigue life analysis of deep water riser under the condition of the stress ratioIt is very important to use safely deep water riser which endure alternating stress load inthe complex ocean environment. Therefore, it is necessary to accurately predict stress andfatigue life of deep water riser. In this paper, based on the theory of fracture mechanics, themodel which considering structural crack is used to analyze fatigue life of deep riser under thecondition of alternating stress, which provides a new theoretical analysis method to predict thefatigue life of riser.更多还原