热采水平井完井管柱力学行为模拟研究

发布时间：2018-01-04 09:11

本文关键词：热采水平井完井管柱力学行为模拟研究　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：热力开采是近年来发展较快的稠油开采技术,己经广泛应用于国内外稠油油藏的开发。热采水平井由于井身结构的限制,注汽工况导致的完井管柱损坏的情况也相当复杂。与常规的稀油开采方式相比,稠油油田出现的最主要问题是套管的变形、错断和泄漏等套损问题,而井口上移、井口冒汽、筛管屈曲等导致的失效问题更是不计其数,给油田生产造成了重大的经济损失。正确认识热采水平井完井管柱在井筒中的受力与变形对提高热采效率、保障完井安全具有非常重要的意义。本文在前人研究成果的基础上,针对热采水平井完井管柱力学认识相对薄弱的问题从理论和数值模拟两方面进行了研究。通过对热采水平井注汽过程中套管柱的受力分析,结合材料力学、弹性力学等相关理论,建立了热采过程中套管柱强度破坏的受力分析模型。建立了热采水平井完井管柱与水泥环(井壁)的有限元仿真模型,并与实验进行了对比验证;根据建立的有限元模型,研究了热采水平井直井段和水平段完井管柱的力学行为及其参数敏感性问题,对预防热采井完井管柱的破坏提出了指导意见。主要研究工作及相关结论如下:(1)根据弹性力学等相关理论,建立了套管在热应力和内外压作用下的三轴应力表达式,以使套管的有效应力控制在相应温度下的最小屈服极限内为准则,建立了一套稠油热采井的套管柱三轴预应力计算方法。(2)热采水平井直井段套管柱力学行为模拟研究:对套管水泥环界面之间的胶结模型和摩擦模型进行了研究,并且与实验对比验证了有限元模型的可靠性;通过对常规固井与三轴预应力固井的套管变形和应力分析,得到了预拉应力在一定范围内可以有效降低套管的Mises应力,起到保护套管的作用;只要选择合适的预拉力,同时保证固井质量,理论上可以避免井口抬升的现象;研究了胶结强度、套管壁厚以及基准温度对套管水泥环界面脱粘的影响,研究发现套管壁厚的增加和基准温度的上升都会增大套管水泥环之间的脱粘率,而当套管水泥环之间的胶结强度足够大时,可以避免井口抬升的现象。(3)热采水平井水平段筛管力学行为模拟研究:根据实体单元筛管模型在高温下的膨胀性能,建立了基于梁单元的等效筛管模型;研究了水平段筛管在350℃高温下的热应力分布及其屈曲行为,对热力补偿器的数量及安放位置进行了优化分析;并且对水平段管柱在注汽工况下的热屈曲特性及其敏感性因素进行了研究,研究发现增大摩擦系数和管柱的壁厚都会增大临界屈曲温度。通过以上研究,形成了一套比较完善的热采水平井完井管柱力学行为仿真方法。本文的研究内容对于发展我国特殊工艺井完井工艺理论具有重要的意义。
[Abstract]:Thermal recovery is a fast development in recent years of heavy oil exploitation technology, has been widely applied to the development of domestic and foreign heavy oil reservoirs. Horizontal well thermal recovery due to well structure, cause steam injection conditions completion pipe string damage situation is quite complex. Compared with the conventional oil mining method, the main problem of heavy oil there is oil casing deformation, dislocation and leakage of casing damage, and wellhead wellhead move, steaming, failure of the screen buckling caused more is too many to count, resulting in significant economic losses to oil production. To improve the thermal efficiency of the deformation and stress the correct understanding of thermal recovery water column in Hirai I well, has very important significance to protect the safety of well completion. In this paper, on the basis of previous research results, the thermal recovery horizontal well completion pipe string mechanical understanding of the relatively weak problem from two aspects of theory and numerical simulation For the study. Based on mechanical thermal recovery casing horizontal steam injection wells in the process of analysis, combined with the related theory of material mechanics, elastic mechanics, established during the thermal recovery of damaged casing string stress analysis model was established. Column and cement thermal recovery horizontal well completion (wall) limited element simulation model, and the results are verified with experiments; according to the established finite element model, study the mechanical behavior of vertical section and horizontal section of horizontal well completion string thermal recovery and parameter sensitivity problem, put forward the guiding opinions on the prevention of thermal recovery well completion pipe string damage. The main research work and conclusions are as follows: (1) according to the elastic mechanics theory, established in three axis casing thermal stress expression force and pressure inside and outside the casing to make effective stress control in the corresponding temperature minimum yield limit as a criterion, establish a set of Heavy oil thermal recovery wells casing prestressed three axis calculation method. (2) simulation of thermal recovery horizontal straight hole casing mechanical behavior: on cementation model and the friction model between the casing cement interface is studied, and the experiment results verify the reliability of finite element model based on conventional casing deformation; well cementing and three axis Prestressed well cementing and stress analysis, the pre tensile stress in a certain range can effectively reduce the casing stress Mises, play a role in protection tube; as long as the choice of the appropriate tension, and guarantee the cementing quality, the theory can avoid the phenomenon of wellhead uplift; bond strength, the effect of casing wall thickness and the reference temperature of debonding on casing cement interface, the study found that increased wall thickness of the casing and the reference temperature will increase between the casing cement debonding rate, and when the casing cement ring The bond strength between the large enough, can avoid the wellhead uplift phenomenon. (3) research on Simulation of thermal recovery horizontal screen: according to the mechanical behavior of expansion performance model of solid element in high temperature screen, an equivalent screen model based on beam elements; on the horizontal section screen at 350 DEG C under high temperature the distribution of thermal stress and buckling behavior, the number of thermal compensator and position are analyzed; and on the level of pipe thermal buckling characteristics of cylinder in steam injection conditions and sensitivity factors were studied. The study found that increased friction coefficient and tube wall thickness will increase by more than the critical buckling temperature. Study, formed a relatively complete set of horizontal well thermal recovery pipe mechanics behavior simulation method. The research content of this paper has important significance for the development of special technology well completion technology theory in China.

【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE925.3

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