【作者】 畅元江；

【导师】 陈国明；

【作者基本信息】 中国石油大学 ， 机械设计及理论， 2008， 博士

【摘要】 本文结合国家高技术研究发展(863)计划海洋技术领域重大项目“深水钻完井关键技术”和中国海洋石油总公司综合科研课题“深水钻井隔水管工程方法研究及双梯度钻井跟踪应用研究”,系统开展深水钻井隔水管设计方法及其应用研究,通过理论研究、数值计算和计算机仿真,在(超)深水钻井隔水管系统设计影响因素分析、深水钻井隔水管(准)静态性能综合研究、深水钻井隔水管响应参数敏感性分析及其预测模型研究、深水钻井隔水管随机非线性动力分析、悬挂模式深水钻井隔水管轴向动力分析、深水钻井隔水管波致长期疲劳分析等方面取得较大的研究进展。主要研究成果总结如下:1 (超)深水钻井隔水管系统设计影响因素分析(超)深水钻井隔水管设计影响因素主要为环境因素与作业因素,前者主要包括水深、波浪、海流,后者主要包括钻井液密度、底部海洋隔水管总成(Lower Marine Riser Package,简称LMRP)与井口防喷器(Blowout Preventer,简称BOP)脱离后钻井隔水管系统悬挂模式、浮力块分布、涡激抑制设备、节流与压井管线的工作压力等。系统辨识了(超)深水钻井隔水管系统设计影响因素,研究了各因素影响隔水管系统设计的机理,分析了各影响因素与隔水管系统设计之间的关系,研究了(超)深水钻井隔水管系统设计方法。研究表明,水深和海流是(超)深水钻井隔水管系统设计最重要的影响因素,隔水管系统设计需要在悬挂模式与连接模式之间循环进行以得到系统最佳配置。2深水钻井隔水管(准)静态性能综合研究提出隔水管准静态分析的理论、原理和方法,开发深水隔水管准静态性能分析系统。系统以隔水管最大Mises应力作为波浪最大相位角判据,以C++ Builder为开发环境,后台调用ABAQUS求解器进行计算,实现波浪最大相位角的自动搜索和隔水管的准静态分析。比较隔水管静态与准静态分析的主要差异,研究了波浪相位角对隔水管准静态分析的影响。从工程应用角度,展开了隔水管静态性能的综合研究。3深水钻井隔水管响应参数敏感性分析及其预测模型研究影响隔水管响应的参数主要有隔水管几何参数、海况参数、浮力块参数和作业参数。隔水管几何参数包括隔水管外径和壁厚,海况参数包括波高,波浪周期,流剖面,浮力块参数包括浮力块外径、浮力块长度和安装位置,作业参数包括张力比(Top Tension Ratio,简称TTR),钻井船平均偏移以及钻井液密度等。隔水管响应参数敏感性分析的目的在于揭示这些参数对隔水管响应的影响,为隔水管设计与系统配置提供依据。基于正交试验方法进行隔水管响应参数敏感性分析,将上述影响隔水管响应的11个因素各取5个水平构建L50(511)正交表,采用准静态分析系统进行有限元计算,对正交试验结果进行极差与方差分析,定量和定性研究了不同参数对隔水管响应的影响。深水钻井隔水管响应预测模型研究目的在于无需进行复杂的有限元计算即可对正常作业的隔水管响应提供一个满足工程需要的粗估计,为隔水管的初期设计阶段提供一种快速求解方案。研究并提出了基于支持向量机(Support Vector Machine,简称SVM)的隔水管响应预测模型,采用正交试验结果训练SVM,随机产生新的试验数据校核SVM预测精度,比较了SVM预测模型与回归模型之间的精度差异,结果表明基于SVM的隔水管响应预测模型可满足工程应用需要。4深水钻井隔水管随机非线性动力分析在对隔水管动态响应数学模型与水动力载荷模型进行研究的基础上,研究了隔水管动态响应分析技术。提出了时域内采用ABAQUS/Aqua软件进行随机波浪与钻井船运动作用下深水隔水管动力分析的方法。为实现隔水管时域随机振动分析,首先进行长峰随机波浪的模拟和模拟波浪的谱估计,然后根据钻井船运动解析式、波浪模拟得到的随机波浪序列和钻井船纵荡响应幅值算子(Respose Amplitude Operator,简称RAO),迭代生成钻井船运动边界条件,最后定义波浪序列和边界条件,考虑隔水管其他的结构、功能与环境载荷进行有限元动态分析。研究了脱离后悬挂隔水管的响应分析技术,分析了悬挂模式隔水管的轴向动态响应。悬挂隔水管动力分析的第一步是确定钻井船的动态升沉响应,硬悬挂模式计算隔水管柱最大允许海况的准则是隔水管无压缩载荷。采用数值计算方法,根据波浪谱与钻井船的升沉RAO得到钻井船的升沉运动响应,再将钻井船的升沉响应时间历程作为隔水管轴向动态分析的动边界进行悬挂隔水管轴向动态分析,得到隔水管不同位置的轴向应力时间历程。研究方法与结论可为隔水管悬挂模式选择、钻井隔水管系统设计与配置及其优化提供参考。5深水钻井隔水管波致长期疲劳分析作为动力疲劳敏感结构,深水钻井隔水管的长期疲劳性能是重要的设计考虑。提出一种深水钻井隔水管波致长期疲劳计算方法,用以计算一阶波浪载荷和波频钻井船运动以及二阶低频钻井船运动引起的长期疲劳。根据波浪散布图定义的短期疲劳工况,首先基于双参数Pierson-Moskowitz波浪谱(简称P-M谱)与钻井船RAO模拟随机波浪与随机钻井船运动,然后进行随机波浪载荷与钻井船运动作用下隔水管非线性动力分析。在得到隔水管响应时间历程的基础上,考虑波浪散点图中所有短期工况的概率,采用自行开发的专用程序实现深水钻井隔水管波致长期疲劳损伤计算。算例计算南海海域1,500m钻井隔水管的波致长期疲劳。重点研究了钻井船运动、顶部张紧力和隔水管单根壁厚对隔水管疲劳损伤的影响。更多还原

【Abstract】 The dissertation focuses on design approach and its application for deepwater drilling risers, which is a part of the“863”High Technology Research and Development Program of China (No.2006AA09A106-4) and the project of“Research on Deepwater Riser Engineering Methods and Trace Study of Dual-Gradient Drilling Technology”sponsored by CNOOC. Design approach and its application for deepwater drilling risers is investigated systemically based on theoretical research, numerical calculation and computer simulation, including analysis of influencing factors for design of ultra-deepwater drilling risers system, comprehensive study on (quasi)static performance of drilling risers, parametric sensitivity analysis and research on response prediction model of drilling risers, nonlinear dynamic analysis of risers subjected to random wave loads and vessel motion, axial dynamic behavior of hung-off drilling risers and long-term wave fatigue analysis of deepwater drilling risers, and so on. The main works are summarized as follows:1 Analysis of Influencing Factors for Design of (Ultra)Deepwater Drilling Risers SystemEnvironmental and operational factors are the main factors that affect the design of (ultra)deepwater drilling risers system. The former include water depth, wave, current, and the latter include drilling fluid density, hung-off mode after disconnection of LMRP(Lower Marine Riser Package) with BOP(Blowout Preventer), and vortex-induced-vibration suppression devices, buoyancy modules distribution, service pressure of choke and kill lines, et al. This paper presents a systemic description of the factors affecting the design of (ultra) deepwater drilling risers system, identifies the mechanism of the factors affecting the design of drilling risers system, and analyzes the relationships between the influencing factors and the design of drilling risers system. The research shows that water depth and current are the most significant factors influencing the design of the drilling riser system, and the design of it should be conducted between hung-off and connected mode to obtain the optimal configuration of the drilling riser system.2 Comprehensive Study on (quasi)Static Performance of Deepwater Drilling RisersTheory, principle and method for quasi-static analysis of deepwater drilling risers are presented in the paper. Quasi-static analysis system for drilling riser by use of ABAQUS in the background is developed in C++ Builder environment. Then, the automatic search for the maximal wave phase as well as the nonlinear quasi-static analysis of the top tensioned drilling riser is implemented. Based on the above research, the results are compared between static and quasi-static analysis, and the effect of wave phase angle on riser quasi-static performance is investigated. In the end, a comprehensive study of riser static performance is made from the viewpoint of engineering application.3. Parametric Sensitivity Analysis and Response Prediction Model of Deepwater Drilling RisersGeometry parameters, seastate parameters, buoyancy modules parameters and operation parameters are the main factors affecting the response of deepwater drilling risers. Geometry parameters include outside diameter and wall thickness of the drilling risers, seastate parameters include wave height, wave period and current profile, buoyancy modules parameters include outside diameter, length and configuration position, and operational parameters include TTR(Top Tension Ratio), drilling fluid density and mean offset of the drilling vessel. The purpose of parametric sensitivity analysis is to disclose the effect of those parameters on drilling riser response, and to provide reference for the design and configuration of drilling riser system. Sensitivity analysis of parameters affecting the response of the riser is conducted based on orthogonal test approach in this paper. L50(511) orthogonal table is built after 11 factors noted previously being considered in orthogonal test with 5 levels adopted in each factor. Finite element calculation is carried out by use of quasi-static analysis system, and range and variance analysis of test results is made. As a consequence, the effect of parameters on riser response is analyzed qualitatively and quantitatively.Research on response prediction model for deepwater drilling risers is to provide a rough estimation on riser response which meets the need of engineering application without complicated finite element calculation, and to provide a simple and applicable solution at the stage of preliminary design of the drilling risers. Response prediction model based on support vector machine(SVM) is investigated and proposed in this paper. SVM is trained by orthogonal test results, and its predication accuracy is checked by randomly generated new test data. The difference in accuracy between SVM and regression predication model is compared, and the result indicates that predication model based on SVM meets the need of engineering application.4 Nonlinear Dynamic Analyses of Deepwater Drilling Risers Subjected to Random Wave Loads and Vessel MotionBased on the theoretical research on mathematical model and hydrodynamic loads model for riser dynamic analysis, analysis techniques of dynamic response for deepwater drilling risers are discussed thoroughly. An approach is proposed for calculating the nonlinear dynamic response of deepwater drilling risers subjected to random wave and vessel motion with finite element solver ABAQUS/Aqua in time domain. Firstly, wave trains and the associated sea surface elevation time history based on the simulation of the long-crested random wave should be determined, then dynamic vessel motion based on the wave train and the specified Response Amplitude Operator(RAO) of the drilling vessel should be determined, and finally finite element dynamic analysis can be performed after definition of wave series, boundary condition, structural and environmental loads is completed.Response analysis technique of the hung-off riser after disconnection is studied, and axial dynamic behavior of it is analyzed. The first step in dynamic analysis of the hung-off riser is to determine the vessel heave motion. The calculation of the maximum permissible sea state for a drilling riser string in a hard hang-off configuration is generally based on a criterion of no compressive loading. By use of numerical calculation method, heave motion of the drilling vessel is determined according to wave spectrum and heave RAO, which is the dynamic boundary condition of the hung-off riser. Then the axial stress time history in the riser at different position is obtained. The related conclusions can provide reference for selection of hung-off mode, drilling riser system configuration and its optimization.5 Long-term Wave Fatigue Analysis of Deepwater Drilling RiserAs a dynamic, fatigue sensitive structure, long-term fatigue performance of the deepwater drilling risers is an important design consideration. An approach of long term wave fatigue analysis for deepwater drilling riser is presented, which can be used to calculate the long term fatigue of drilling risers subjected to 1st order wave force, wave frequency vessel motion and 2nd order low frequency vessel motion. By use of the proposed method, according to the short term fatigue case defined by the wave scatter diagram, random wave and random vessel motion require to be determined based on the dual parameters of wave spectrum and the RAO of the drilling vessel. Then, nonlinear dynamic analysis of the drilling riser under random wave loads and vessel motion boundary condition can be performed. Based on the response time history obtained by random nonlinear dynamic analysis, considering the probabilities of short term cases in the wave scatter diagram, a self-developed special program is employed to calculate the long term wave fatigue. As an example, long term wave fatigue of the 1,500m deepwater drilling riser in South China sea is calculated. The effect of drilling vessel motion, top tension and wall thickness of the riser joint on fatigue damage of drilling riser is mainly investigated.更多还原