小井眼管柱动力学研究

【作者】 张恒；

【导师】 刘清友； 徐学军；

【作者基本信息】 西南石油学院 ， 机械工程， 2005， 硕士

【摘要】 随着油气勘探开采的不断进行,国内主要油田逐渐进入了开发中后期,不同程度地出现了套管变形损坏、井下落物事故不易处理以及井下水锥或气锥等情形,陆续有部分油水井被迫废弃、闲置,严重制约了油田的发展。为了降低这种损失发挥老井潜力,本文在总结国内外研究成果的基础上,分析并建立了扶正器安装与否两种情况下小井眼完井管柱起下钻时摩阻的大小和大钩载荷;完成了减扭接头对小井眼管柱的减扭降摩分析;最后对小井眼管柱进行了纵向、扭转和横向振动的动力学分析。 本论文的主要研究内容主要包括以下几个方面: (1)在分析国内外研究现状的基础上,对于不带扶正器的完井管柱采用了软杆模型计算摩阻。将管柱分为若干单元段计算,并在每一单元段的质心上建立局部坐标系,实现对每一单元管柱进行受力分析。从而运用微分几何的知识将单元管柱上的力投影到大地坐标系中,迭加得到大钩载荷; (2)深入了解扶正器工作机理后,将弯曲管柱分别投影到井斜平面和方位平面上计算,从而将三维问题转化为二维问题。采用了刚杆模型计算带扶正器的完井管柱的摩阻,运用纵横弯曲梁理论和三弯矩方程组成的多元线性联立方程组并求解,从而使计算结果更接近实际工况; (3)分析了减扭接头和其他几种常用减扭工具的结构、工作机理。建立模型时将空间的钻柱分别投影到井斜平面和方位平面上,运用纵横弯曲梁理论完成了减扭接头对侧钻小井眼下钻柱的减扭降摩效果分析; (4)运用单元质量法建立小井眼管柱动力学模型;通过对模型的求解获得了纵向、横向和扭转振动的固有频率和经转化得到的临界转速,以便更好地运用到现场; (5)利用Visual Basic6.0语言编制相应计算程序实现对模型的求解。在计算中采用了二分法、追赶法等计算精度高、速度快的数值计算法。 总之,本论文在比较分析了多个力学模型的基础上,建立了更为准确的小井眼管柱摩阻计算模型和钻柱固有频率计算模型,编制了相应的计算程序使计算更加简便快捷,并通过实际算例进行了验证,结果表明,计算结果与实际基本吻合。本文的研究工作结合实际,本文的研究成果为工程设计人员和施工人员提供参考依据。更多还原

【Abstract】 With the coming of inland main oilfield after the middle of exploitation, there are some oilfields can’t maintain usual produce and cause that producing of oil and gas get down gradually, because it’s not easy to deal with event down hole and other reasons such as down-hole water cone or gas cone, more and more oilfield came to waste well vacant well, these obstructed the development of oilfields. In order to reduce the cost of drilling, especially to make use of potentiality of old oilfield. In this paper, on basis of collecting information in home and oversea, analyzed amount of friction and hook load through deducing the models of calculating friction of completion casing with centralizer and without centralizer; analyzed torque of drilling pipe with Drilling Pipe Protesters; finally, analyzed pipe’s orientation, horizontal, and torques fluttering in order to guide field processing.The main characteristics of the research in this paper are as follows:(1) Information about dynamics, mechanics, calculating friction and NRPP is collected in home and overseas.(2) On the basis of analyzing the development trends and technical characteristics, using flexible hose calculated completion pipe with centralizers. Divide all casing into unit casing, funding a local coordinate on every unit, so as to analyze unit pipe simply. Then project the force on unit to total coordinate(3)Consult relevant materials have finished supporting the introduction to centralizers’ working mechanics. Project bend pipe to Inclination Plane and Azimuth Plane, so turn complicate 3-D problem to two 2-D bend problem .In every plane, calculated friction of completion pipe with centralizers by gripe string model, on the basis of analyzing mechanical characters of casing which contain some centralizers , used vertically and horizontally distort model ,used vertically and horizontally distort principle and linearity equations that is made up of three distort equation ,then the results are close to actual friction.(4) On the basis of preferring to relative materials, introduced working mechanics of NRPP and a few reducing torque tools, the same to completion pipe with centralizer, project drill string in space to two planes, turn complication problem to two simple level problems, found and completed the mechanic model to calculate reduced torque on string that is used in inside drill in slim hole.(5) On the basis of research on basic theory of string dynamics developed the basic theory of pipe dynamics, used method of unit quality to calculate dynamicsmodel for pipe in slim hole and pipe dynamics of horizontal well. And got vertical, horizontal and turning back the natural frequency of vibration and transformed to the critical rotational speed received, in order to use this result to guide field processing.(6) Programmed calculation program to calculate by "Visual Basic6.0.In the process of programming, made the result be exactitude through symmetric dividing method and catch up method in programs.To sum up, on the basis of analysis of a few mechanics models, created models that is used to calculate friction which is more closed to fact, programmed serial program in order to calculate quickly and conveniently and demonstrated it through examples ,so models was proved to be accord with requirement in engineering.更多还原