本文選題：鉆柱屈曲 + 臨界屈曲載荷��； 參考：《西南石油大學(xué)》2015年碩士論文

【摘要】：受井眼約束鉆柱的屈曲行為,對(duì)鉆井諸多方面都有不良影響,會(huì)引起鉆柱摩阻和扭矩的顯著增加,甚至使管柱“鎖死”,導(dǎo)致鉆壓傳遞困難、鉆柱疲勞破壞等井下復(fù)雜情況。特別是隨著水平井、大位移井、多分支井的推廣應(yīng)用,受井眼約束的鉆柱屈曲問題研究的重要性更加突出,鉆柱屈曲研究已成為的鉆柱優(yōu)化設(shè)計(jì)的熱點(diǎn)問題。 本文基于彈性力學(xué)力學(xué)理論,考慮鉆柱自重和井眼彎曲的影響,建立了不同井段(垂直段、斜直段、增斜段、降斜段)鉆柱屈曲力學(xué)分析模型,推導(dǎo)了鉆柱正弦屈曲臨界載荷和螺旋屈曲臨界載荷計(jì)算模型,計(jì)算了管柱屈曲后井壁接觸載荷。針對(duì)不同尺寸鉆柱,分析了井斜角、井眼曲率對(duì)鉆柱屈曲臨界載荷和接觸力的影響。在斜直井段,鉆柱臨界屈曲載荷與井斜角成正比,水平段中鉆柱躺在井眼低邊,穩(wěn)定性要高于斜直井段鉆柱；彎曲井段影響鉆柱屈曲最重要的因素為井眼曲率,增斜井段造斜率與鉆柱臨界屈曲載荷成正比,降斜井段則相反；隨著軸向力的增大,鉆柱與井壁的接觸力也逐漸增大。 本文采用非線性大變形理論,建立了鉆柱幾何非線性和接觸非線性的有限元鉆柱屈曲分析模型,模擬了不同井段鉆柱屈曲變形演化過程及其對(duì)應(yīng)的接觸力矢量圖。由于自重作用,斜直井段鉆柱處于井眼低邊,隨著軸向載荷的增大會(huì)使鉆柱沿井眼低邊屈曲成正弦狀,鉆柱發(fā)生正弦屈曲后,隨著軸向載荷的進(jìn)一步增加會(huì)使鉆柱由正弦屈曲向螺線屈曲演化,當(dāng)載荷達(dá)到臨界值時(shí),管柱的屈曲形狀會(huì)從正弦屈曲變成螺旋屈曲,從正弦屈曲到螺旋屈曲是一個(gè)瞬態(tài)的過程,當(dāng)鉆柱發(fā)生螺旋屈曲后,軸向力繼續(xù)增大,會(huì)使鉆柱與井壁的接觸力激增；增斜井段隨著井眼曲率的增加,臨界屈曲載荷增加,屈曲從鉆柱底部開始；降斜井段則相反,軸向載荷先將部分鉆柱推向井眼高側(cè),然后從底端開始發(fā)生屈曲,隨后頂端也開始發(fā)生屈曲,鉆柱中部最后發(fā)生屈曲,并且降斜井段很容易發(fā)生屈曲。 論文對(duì)比分析了鉆柱屈曲解析解和有限元模擬結(jié)果的差異,模擬結(jié)果與理論計(jì)算值相對(duì)變化在15%以內(nèi),證明采用有限元分析方法確定鉆柱屈曲臨界載荷的方法是可行的。
[Abstract]:The buckling behavior of drill string restrained by borehole has a bad effect on many aspects of drilling, which will cause obvious increase of friction and torque of drill string, and even make string "lock", resulting in difficult transmission of drilling pressure, fatigue failure of drill string and other complicated downhole conditions. Especially, with the popularization and application of horizontal well, extended reach well and multi-branch well, the research on the buckling of drill string constrained by borehole becomes more and more important. The buckling of drill string has become a hot issue in the optimum design of drill string. Based on the theory of elasticity, considering the influence of drill string weight and borehole bending, different well sections (vertical section, oblique straight section, increment section) are established in this paper. The critical load of sinusoidal buckling and spiral buckling of drill string is derived, and the contact load of shaft wall after string buckling is calculated. The effects of inclined angle and borehole curvature on the critical load and contact force of drill string buckling are analyzed. The critical buckling load of the drill string is proportional to the angle of the well, and the drill string lies on the low side of the hole in the horizontal section, and the stability of the drill string is higher than that of the drill string in the oblique straight section, and the most important factor affecting the buckling of the drill string in the curved section is the borehole curvature. The slope rate of the increased slope section is directly proportional to the critical buckling load of the drill string, while the downslope section is opposite, and the contact force between the drill string and the shaft wall increases gradually with the increase of axial force. The nonlinear large deformation theory is used in this paper. The finite element buckling analysis model of drill string with geometric nonlinearity and contact nonlinearity is established, and the evolution process of drill string buckling and its corresponding contact force vector diagram are simulated. Due to self-gravity, the drill string in the oblique straight section is on the low side of the hole. With the increase of axial load, the drill string will buckle into a sinusoidal shape along the low side of the hole, and the drill string will buckle after sinusoidal buckling. With the further increase of axial load, the drill string evolves from sinusoidal buckling to helical buckling. When the load reaches the critical value, the buckling shape of the string changes from sinusoidal buckling to spiral buckling. It is a transient process from sinusoidal buckling to helical buckling. When the screw buckling occurs, the axial force continues to increase, which will make the contact force between the drill string and the shaft wall surge, and the critical buckling load increases with the increase of borehole curvature. The buckling begins at the bottom of the drill string, whereas in the downhill section, the axial load first pushes part of the drill string to the high side of the hole, then begins to buckle from the bottom, and then the top also begins to buckle, and the central part of the drill string finally buckles. The difference between the analytical solution of drill string buckling and the result of finite element simulation is analyzed, and the relative change between the simulation result and the theoretical value is less than 15%. It is proved that the finite element analysis method is feasible to determine the critical buckling load of drill string.
【學(xué)位授予單位】：西南石油大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TE921.2

【共引文獻(xiàn)】

相關(guān)期刊論文 前10條

1 ;Stability and vibration of a helical rod constrained by a cylinder[J];Acta Mechanica Sinica;2007年02期

2 林海花;王言英;;波流共同作用下隔水管動(dòng)力響應(yīng)非線性分析[J];船舶力學(xué);2009年02期

3 馮曉東;李敬元;;井下作業(yè)管柱圖形可視化軟件設(shè)計(jì)[J];重慶科技學(xué)院學(xué)報(bào)(自然科學(xué)版);2010年06期

4 張旭;劉小利;夏宏南;陶謙;彭明旺;;螺桿鉆具壓降分析計(jì)算[J];斷塊油氣田;2006年06期

5 李子豐,趙新瑞,趙德云;通用下部鉆具三維小撓度靜力分析的數(shù)學(xué)模型及應(yīng)用[J];工程力學(xué);2000年06期

6 范慕輝,焦永樹,于文英;三維井孔軸線的幾何描述與套管摩阻的數(shù)值模擬[J];工程力學(xué);2005年02期

7 談梅蘭;甘立飛;王鑫偉;;斜直井內(nèi)鉆柱的非線性螺旋屈曲[J];工程力學(xué);2007年S2期

8 談梅蘭;何小寶;王鑫偉;;井眼內(nèi)鉆柱屈曲分析時(shí)端部約束方程的合理性[J];工程力學(xué);2008年05期

9 姜麗紅;談梅蘭;;端部約束對(duì)鉆柱正弦屈曲的影響[J];工程力學(xué);2010年12期

10 郭金根;劉宏濱;;送電線路酒杯型鐵塔塔頭受力分析[J];廣東電力;2011年06期

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