摘要
底部钻具组合(BHA)的横向振动特性对井眼轨迹控制及井壁稳定性有重要的影响。目前,应用于BHA分析的数学方法主要包括有限差分法、能量法、有限元法和加权余量法。针对带预弯结构和稳定器BHA(Pre-bent BHA)的结构特征,提出一种可快速求解Pre-bent BHA横向振动响应的新型分析方法。首先,建立小变形条件下Pre-bent BHA的三维静力学模型,并用加权余量法和切点优化法求解该模型,得到其在三维井眼内的变形特征;其次,在静力学计算的基础上,根据Pre-bent BHA与井壁的接触特征来确定其上切点的位置,并以此切点位置定义Pre-bent BHA的上边界;随后建立Pre-bent BHA的有限元模型并求解其模态特征;最后,在考虑井壁约束的条件下,利用振型叠加法求解其稳态动力学响应,计算了实际钻井过程中使用的Pre-bent BHA的动态特性,得到其临界转速及工作状态图版。通过与相同结构参数(除弯角外)的常规BHA动态特性对比发现,合适的预弯结构可以大幅改善BHA的横向振动特性。该方法可用于钻前分析以便合理地设计Pre-bent BHA的结构并优选钻井参数,也可用于钻后分析找出Pre-bent BHA失效的初步原因。
The lateral vibration characteristic of bottom-hole assembly(BHA)has significant influences on well path control and borehole stability.Up to now,there are mainly four types of mathematical methods applied to BHA analysis,including finite difference method,energy method,finite element method and weighted residual method.A new method for quickly solving the lateral vibration response of Pre-bent BHA was put forward in this study aiming at the structural characteristics of BHA with Pre-bent configuration and stabilizer.Firstly,a3 D static model of Pre-bent BHA was established under the small-deformation condition and solved by weighted residual method and inner and outer optimization method,so as to obtain the deformation characteristics in 3 D borehole.Secondly,based on the static calculation,the location of tangent point was defined by the contact characteristics between Pre-bent BHA and borehole wall,which was used to define the upper boundary of Pre-bent BHA.Subsequently,the finite element model of Pre-bent BHA was established to solve its modal characteristics of lateral vibration.Under considering the case of borehole wall constraint,the mode superposition method was used to solve its steady-state dynamic response.Meanwhile,the dynamic performance of Pre-bent BHA used in actual well-drilling process was calculated to obtain its critical rotary speed and working status chart.Through comparing with the dynamic characteristics of regular BHA with the same structural parameters,it was discovered that reasonable Pre-bent structure can greatly improve the lateral vibration characteristics of BHA.Moreover,this method can be used for Pre-drilling analysis,so as to make a reasonable design of Pre-bent BHA configuration and optimize drilling parameters,which can also be applied to find out the initial reasons for the failures of Pre-bent BHA.
作者
张鹤
狄勤丰
覃光煦
陈薇
王文昌
陈锋
Zhang He;Di Qinfeng;Qin Guangxu;Chen Wei;Wang Wenchang;Chen Feng(Shanghai Institute of Applied Mathematics and Mechanics,Shanghai University,Shanghai 22012,China;Shanghai Key Laboratory of Mechanics in Energy Enginee ring,Shanghai 200072, China;School of Mechatronics Engineering and Automation,Shanghai University,Shanghai 200072, China)
出处
《石油学报》
EI
CAS
CSCD
北大核心
2017年第12期1441-1447,共7页
Acta Petrolei Sinica
基金
国家自然科学基金项目(No.U1663205
No.51174130
No.51704191)
上海市重点学科建设项目(S30106)
上海市部分地方院校能力建设项目(12160500200)
上海市高原高峰学科建设项目和上海市扬帆计划项目(17YF1428000)资助
关键词
预弯底部钻具组合
横向振动特性
加权余量法
有限元法
模态分析
稳态动力学响应
Pre-bent BHA
lateral vibration characteristic
weighted residual method
finite element method
modal analysis
steady- state dynamic response