-
摘要: 为了研究地球介质中钻凿较深的斜井(这种井既受到内压又受到非静水应力场的作用),有必要发展一种分析表述方式.这种表述方式包括井孔周围应力的三维分析,并把它和井孔内压组合后,求出总应力分布的近似解.在实际现场条件下,井孔的取向、原地应力和岩层层面倾斜都可能是任意的.对井孔的拉伸破坏和剪切破坏都进行了研究.当井孔最小主应力超过拉伸强度时,出现拉伸破坏,这就是拉伸破坏准则.对剪切破坏而言,采用了各向异性材料的修正的Drucker-Prager破坏准则.为了研究材料的各向异性、岩层面倾斜度和原地应力对井孔稳定的影响,进行了参量研究.参量研究结果表明,井孔稳定性明显地受到井孔高倾斜度、材料高度各向异性、原地应力条件和岩层面高倾斜度的影响.文中也研究了弹塑性介质中井孔的稳定性问题.为了弄清井孔周围塑性区范围的大小和塑性区内的材料各向异性性质,利用弹性理论和塑性理论给出了数学公式.同时还研究了竖直井孔在静水压力作用下,地球介质是横观各向同性时的钻井情况.为此,也对地球介质的塑性性能受材料各向异性的影响进行了参量研究.结果指出,井孔周围的应力分布、塑性区域的大小和破坏压力都深受材料各向异性程度和原地超负荷应力值的影响.我们观察到,随着地球介质的各向异性程度增大,井孔的稳定性降低.
-
[1] Aadnoy B S.Continuum mechanics analysis of the stability of boreholes in anisotropic rock formations[D].Ph D Thesis.Norway:Norwegian Institute of Technology,University of Trondheim,1987. [2] Ong S H.Borehole stability[D].Ph D Dissertation.Norman OK:University of Oklahoma,1994. [3] Lekhnitskii S G.Theory of Elasticity of an Anisotropic Body[M].Moscow:Mir Publishers,1981. [4] Amader B.Rock anisotropy and theory of stress measurements[A].In:Brebbia,Orszag Eds.Lecture Notes in Engineering[C].Springer Verlag,1983. [5] Aadnoy B S.A complete elastic model for fluid-induced and in-situ generated stresses with the presence of a borehole[J].Energy Sources,1987,9:239~259. [6] Bradley W B.Failure of inclined boreholes[J].Journal of Energy Resources Technology Trans,ASME,1979,101:232~239. [7] Hsiao C.Growth of plastic zone in porous medium around a wellbore[J].Offshore Technology Conference,1988,26:439~448. [8] Westergaard H M.Plastic state of stresses around a deep well[J].Journal of the Boston Society of Civil Engineers,1940,27(1):1~5. [9] Gnirk P F.The mechanical behavior of uncased wellbores situated in elastic/plastic media under hydrostatic stress[J].Society of Petroleum Engineers Journal,1972,12:49~59. [10] Risnes R,Bratli R K,Horsud P.Sand stresses around a wellbore[J].Society of Petroleum Engineers Journal,1982,22:883~898. [11] Biot M A.Theory of elasticity and consolidation for a porous anisotropic solid[J].Journal of Applied Physics,1941,26(2):182~185. [12] Yew C H,Li Y.Fracture of a deviated well[J].SPE Production Engineering,1988,3:429~437. [13] Chen Dar-Hao.Three dimensional testing and constitutive modeling of coal for analysis of ground subsidence due to mining[D].M S Thesis.Norman OK:University of Oklahoma,1992. [14] Drucker D C,Prager W.Soil mechanics and plastic analysis or limit design[J].Quart Appl Math,1952,10:157~165. [15] Faruque M O,Chang C.New cap model for failure and yielding of pressure sensitive materials[J].Journal of Engineer Mechanics Division,ASCE,1986,112:1041~1053. [16] Najjar Y M.Constitutive modelling and finite element analysis of ground subsidence due to mining[D].Ph D Thesis.Norman OK:University of Oklahoma,1990. [17] Lama R D,Vutukuri V S.Handbook on Mechanical Properties of Rocks[M].Series on Rock and Soil Mechanics Vol.Ⅱ,Ohio:Trans Tech Publications,1978. [18] Infante E F,Chenevert M E.Stability of boreholes drilled through salt formations displaying plastic behavior[J].Society of Petroleum Engineers Drilling Engineering(SPEDE),1989,4:57~65. [19] Gupta D J.Stability of boreholes in a transversely isotropic geologic medium[D].M S Thesis.Norman OK:University of Oklahoma,1994. [20] Aadnoy B S.Stability of highly inclined boreholes[J].SPEDE,1987,2:364~374. [21] Aadnoy B S.Modeling of the stability of highly inclined boreholes in anisotropic rock formations[J].SPEDE,1988,2:259~267. [22] Aadnoy B S.Method for fracture-gradient prediction for vertical and inclined boreholes[J].SPEDE,1989,4:99~103. [23] Aadnoy B S.Stresses around horizontal boreholes drilled in sedimentary rocks[J].Journal of Petroleum Science and Engineering,1989,2:349~360. [24] Aadnoy B S.Effects of reservoir depletion on borehole stability[J].Journal of Petroleum Science and Engineering,1991,5:57~61. [25] Bratli R K,Risnes R.Stability and failure of sand arches[J].Society of Petroleum Engineers Journal,1981,21:236~248. [26] Tsai S W,Wu E M.A general theory of strength for anisotripic materials[J].J Composite Material,1971,5:58~80.
点击查看大图
计量
- 文章访问数: 2306
- HTML全文浏览量: 44
- PDF下载量: 568
- 被引次数: 0