RWD随钻扩眼下部钻具组合设计与力学行为研究

【作者】 吴应凯；

【导师】 陈平； 杨万盛；

【作者基本信息】 西南石油学院 ， 油气井工程， 2004， 博士

【摘要】 RWD随钻扩眼技术不需先钻一个领眼，再下入扩眼器进行扩眼，使钻井和扩眼过程一次完成，节约钻井费用。RWD随眼扩眼工具由领眼钻头、领眼扶正垫、导眼冀、扩孔刀冀等组成，其分段式设计为领眼钻头和井下钻具组合选择提供较大的灵活性，并满足大部分特定井身轨迹严格控制的要求，具有工具结构简单，无活动部件，扩眼尺寸稳定规则的特点。RWD随钻扩眼是解决复杂深井阻卡、非常规井身结构应用和提高固井质量的有效手段。目前这项技术掌握在国外技术服务公司手中，只做技术服务，工具研制和钻具组合设计原理没有公开报道过。近年来国内开始了这种类工具的研制与现场试验。加快国内随钻扩眼技术的发展与应用，进行随钻扩眼钻井组合设计及其受力分析研究，适应复杂深井超深井钻井的发展，具有重要的现实意义。本文针对国内生产的RWD随钻扩眼工具，进行了RWD钻具组合设计及其力学特性、动力学行为、扩眼器破岩机理的系统分析研究，揭示RWD随钻扩眼系统钻进时的受力状态，为提高RWD随钻扩眼技术的应用水平提供了理论依据。 考虑到钻柱组合受力和变形的几何非线性，本文采用小应变一大变形弹性力学分析原理与方法来研究RWD钻具组合受力变形特征，并将扩眼扭矩载荷引入，建立了RWD钻具组合受力变形三维有限元分析模型，模型更真实地反映了井下钻具组合的变形和强度特性。本文提出了以钻头(领眼钻头、扩眼器)处的侧向力和转角为主要性能指标，并综合钻头、稳定器、扩眼器、钻具与井壁接触点的变形及受力情况，确定随钻扩眼下部钻具组合的力学特性，为评价和分析随钻扩眼钻具组合力学特性提出了明确的力学指标。设计和分析了以下钻具组合的力学特性：①光钻铤随钻扩眼钻具组合；②带单稳定器的随钻扩眼钻具组合；③带双稳定器的随钻扩眼钻具组合；④带三稳器的随钻扩眼钻具组合。为随钻扩眼钻具组合的优化设计和施工提供了科学的理论依据。 在考虑扭转载荷的基础上进行的三维钻柱组合强度分析，对随钻扩眼下部钻具组合的变形、钻具组合的弯矩和应力大小及其分布规律进行了研究。随钻扩眼钻柱所受的周向载荷，即扭转载荷对变形和强度影响显著。在优化设计随钻扩眼组合和实际施工作业中，应充分重视钻具组合的强度问题。 考虑随钻扩眼钻具组合在井下的实际受力情况，对随钻扩眼钻进钻柱扭转振动进行了三维有限元模拟，提出了研究扩眼器的质量偏心、钻机顶部支撑等因素对扭转振动作用的力学分析模型，并讨论了随钻扩眼钻具组合的扭转振动频率和动力学强度等力学问题，通过分析提出了在实际施工作业中减少扭转振动带来危害的技术措施。 随钻扩眼过程中，扩眼器与所扩地层之间的岩石力学耦合分析对研究随钻扩眼钻进破岩机理，是一个极为重要的研究内容。本文建立了弹塑性有限元力学分析模型，运用莫尔一库仑强度准则，用数值分析的原理和方法模拟了随钻扩眼时扩眼器破岩的力学机理。并对井眼围岩变形和应力分析及强度进行了研究，为研究随钻扩眼的破岩规律和对扩眼器进行改进提供了一种方法和研究的基础。关键词:RWD下部钻具组合力学特性钻柱强度扭转振动破岩更多还原

【Abstract】 The reaming while drilling (RWD) is one technology that the drilling and reaming works are finished at the same time without drilling a hole before the reamer been put downhole to ream the borehole, it cuts the drilling cost. The RWD tool is made of a pilot bit, a pilot stable pad, a pilot-hole blade, and reaming blades. It’s segmental design offers more alterability for the BHA and the pilot bit choices, meeting requests of most specifically trajectories strictly control, and It has the following characteristics: the simple tool structure, without active parts, the stable and regular reaming size, etc. The RWD is an effective means to solve sticking in complex deep wells, apply the un-conventional well profile and improve cementing quality. The technology is in control of overseas technique service company, providing technique service only. The data of tools development and BHA design principle were not published. Recently, the type of tool developments and fields experimentation were taken in our country. It is very important to quicken domestic RWD technology development and application, research on RWD BHA design and mechanics analysis, adapting the deep and ultra-deep wells development. In the paper, systematic researches of RWD BHA design and it’s mechanics characteristics, dynamical behavior and reaming rock- breaking mechanism were made to uncover the RWD system’s mechanics laws, provided theory foundation to enhance RWD technology application level.Considering the geometric non-linear questions of BHA force and it’s deformation, the elastic mechanics analysis theories and methods of the little-strain & large -deformation were to adopted in the paper to study the load and deformation of RWD BHA. At the same time, after considering RWD tool’s torsion , a three-dimension finite element analysis model was established. The BHA deformations and strength characteristics can be simulated by the model more really. The lateral force and the rotary angle on the bit (pilot hole bit, reamer) are main performance indexes to RWD BHA mechanics performances, and synthesizing the effects of deformations and mechanics behaviors of the bit, the stabilizers, the reamer, the contact point between the drilling string and borehole . So a clear mechanics index was put forward to confirm RWD BHA mechanics characteristics and evaluate analyze RWD behavior. Some typical RWD BHA designs and mechanics characteristics analysis were taken The BHAincludes : 1) RWD BHA without the stabilizer;2). RWD BHA with a single stabilized). RWD BHA with two stabilizers; 4). RWD BHA with three stabilizers. These researching achievements offer some scientific theories foundations for the RWD BHA optimization designs and it’s construction.Three-dimension drilling stem strength analysis based on considering the torsion load and studies deformation, bend-moment, stress, the distribution characteristics of RWD BHA was made . The tangential load of the RWD string, i.e. the torsion load, does a striking effect on its deformation and strength. So RWD string’s strength should be fully attached importance to in optimization RWD designs and in the actual construction works.Considering the load of RWD BHA actually in the borehole, a three-dimension finite element simulation of RWD torsion vibration was finished.. In the meantime; a mechanics analysis model is established which embodies the effecting factors as the reamer’s quality eccentricity, the top rig’s support, etc. Some discussion such as the RWD BHA’s torsion vibration frequency, its dynamic characteristics was done. At last, a technology methods is offered to avoid the dangers bring about by the torsion vibration.In the course of reaming, the rock mechanics’ coupling analysis between the reamer and the rock is very important for studying rock- breaking mechanism. The elastic-plastic finite element mechanics analysis models were established, by using the numerical analysis principles and methods, reamer rock-breaking mechanism simulations was done applying the Mohre-Kulun strength rule, then the studies on更多还原