Model for Collapsing Strength Calculation of Worn Casing
-
摘要: 套管磨损后其承载能力降低,因此对磨损套管进行抗挤毁能力预测或评估就显得尤为重要。采用数值模拟和实物试验相结合的方法,系统分析了磨损套管的挤毁失效机理、影响抗挤强度的因素及影响规律。分析得出,月牙形磨损套管的挤毁属"三铰"失稳,严重磨损处首先屈服进入塑性区并产生很大变形,从而导致整体结构发生弹塑性失稳。磨损套管的抗挤强度随剩余套管壁厚、磨损半径和轴向载荷分别呈指数、幂函数和线性函数式变化。以此为基础,从未磨损套管实际抗挤强度计算入手,建立了完整的磨损套管抗挤强度计算模型,并对模型进行了试验验证,试验结果表明,模型计算值与试验实测值的相对误差在5%以内。所建立的磨损套管抗挤强度计算模型可用于磨损套管和未磨损套管抗挤强度的预测和评估。Abstract: Since bearing capacity of a casing will reduce when the casing is worn,it is very important to predict or evaluate the collapse capacity of the worn casing.To combination numerical simulation and actual tests,the collapsing failure mechanism of worn casing and the factors and rules impacting the collapse strength were studied.Collapse of crescent worn casing belongs to "three hinged" instability.The severely-worn position on the casing was yielded into plastic zone first and deformed greatly,which resulted in the plastic instability of the whole structure.The collapsing strength of the worn casing presented changes of exponent,power function,and linear trend with the residual casing wall thickness,wear radius and axial load respectively.Based on this study,the calculation model of collapsing strength for the whole worn casing were established and the model was verified by tests,which showed the relative error between calculated from the model and those tested was within 5%.
-
Keywords:
- casing abrasion /
- casing collapse /
- compressive strength /
- crooked hole /
- mathematical model
-
-
[1] Yukihisa K,Yasushi T,Toshitaro M.Effect of wear and bending on casing collapse strength.SPE 24597,1992.
[2] Song J S,Bowen J,Klementich F.The internal oressure capacity of crescent-shaped wear casing.SPE/IADC 23902,1992.
[3] 王小增,杨久红,窦益华.套管磨损后剩余壁厚及剩余强度分析[J].石油钻探技术,2008,36(2):14-17. Wang Xiaozeng,Yang Jiuhong,Dou Yihua.Analysis of casing remaining thickness and residual strength after wearing[J].Petroleum Drilling Techniques,2008,36(2):14-17. [4] 窦益华,张福祥,王维君,等.井下套管磨损深度及剩余强度分析[J].石油钻采工艺,2007,29(4):36-39. Dou Yihua,Zhang Fuxiang,Wang Weijun,et al.Analysis on wear depth and residual strength of downhole casing[J].Oil Drilling Production Technology,2007,29(4):36-39. [5] 关舒伟,李春福,李学艺,等.非均匀外挤压力作用下内径偏磨套管的应力分析[J].石油钻探技术,2009,37(2):38-40. Guan Shuwei,Li Chunfu,Li Xueyi,et al.Stress analysis of worn casing under heterogeneous external pressure[J].Petroleum Drilling Techniques,2009,37(2):38-40. [6] 曾德智,林元华,施太和,等.磨损套管抗挤强度的新算法研究[J].天然气工业,2005,25(2):78-80,106. Zeng Dezhi,Lin Yuanhua,Shi Taihe,et al.New algorithm of collapsing strength of wearing casing[J].Natural Gas Industry,2005,25(2):78-80,106. [7] 曾德智,龚龙祥,付建红,等.全井段套管磨损量预测与磨损后抗挤强度计算方法研究[J].钢管,2010,39(增刊1):11-16. Zeng Dezhi,Gong Longxiang,Fu Jianhong,et al.Study on prediction of abrasion amount of and calculation method for post-abrasion collapse strength of full-length well casings[J].Steel Pipe,2010,39(supplement 1):11-16. [8] 廖华林,管志川,马广军,等.深井超深井内壁磨损套管剩余强度计算[J].工程力学,2010,27 (2):250-256. Liao Hualin,Guan Zhichuan,Ma Guangjun,et al.Remaining strength calculation of internal wall worn casing in deep and ultra-deep wells[J].Engineering Mechanics,2010,27 (2):250-256. [9] 李廉锟.结构力学[M].3版.北京:高等教育出版社,1996:56-63. Li Liankun.Structural mechanics[M].3rd ed.Beijing:Higher Education Press,1996:56-63. [10] 王长进.钻杆与套管摩擦磨损研究.秦皇岛:燕山大学车辆与能源学院,2007. Wang Changjin.Friction and wear research of the drill pipe and casing.Qinhuangdao:Yanshan University,College of Vehicles and Energy,2007. [11] 宋根才.复杂井况水平井套管损坏机理及预防技术研究.东营:中国石油大学(华东)机电工程学院,2010. Song Gencai.Study on casing damage mechanism and prevention.Dongying:China University of Petroleum(Huadong),College of Mechanical and Electronic Engineering,2010. [12] Tamano T,Mimaki T,Yanagimoto S.A new empirical formula for collapse resistance of commercial casing[J].Journal of Energy Resources Technology,1983,43(5):489-495.
计量
- 文章访问数: 2993
- HTML全文浏览量: 79
- PDF下载量: 3363
下载:
