海洋大位移钻井井眼净化技术优化研究

发布时间：2018-03-19 09:46

本文选题：大位移井　切入点：岩屑运移模拟　出处：《西安石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：井眼净化技术是大位移钻井的关键技术之一,保证井眼清洁对安全快速钻进具有十分重要的意义。大位移井具有井斜角大、水平段长等特点,钻进过程中岩屑颗粒很容易沉积到井眼低边而形成岩屑床,且在隔水管存在的情况下,岩屑颗粒的运移易受海洋低温、环空返速、钻杆旋转以及岩屑粒径等因素的影响。若不能保持良好的井眼清洁,将会引起憋泵、卡钻等诸多问题,严重影响着钻井效率、钻井成本、井身质量及钻井安全等。因此,研究井眼净化技术对于海洋大位移井的快速发展具有很大的指导意义。本文在充分调研岩屑运移相关理论的基础上,采用数值模拟和理论研究相结合的方法,开展了海洋大位移钻井井眼净化技术的优化研究。借助Fluent流体力学软件模拟并分析了井筒环空岩屑颗粒运移的影响因素,并确定了各因素的影响程度;总结并归纳现有井眼净化的计算模型,针对其存在的不足之处,以斜井段为主要研究对象,建立了一套简单而实用的井眼净化模型,并通过实例计算验证了模型的准确性;基于所建模型,采用Visual Basic 6.0作为集成开发环境,研发了井眼净化效果预测与分析软件,并对该软件的合理性和准确性进行了验证。研究结果表明:环空温度存在临界值,且温度高于此临界值环空岩屑体积浓度基本不变;随着钻井液n、k值的增大,环空岩屑体积浓度显著减小,说明携岩效率对钻井液流变参数较为敏感;在所有的影响因素中,钻井液n、k值的影响最大,其次是环空返速、岩屑粒径及环空温度,而钻井液密度和钻杆旋转对岩屑运移规律的影响相对较弱;在现有计算模型的基础上,通过简化计算参数,建立了一套简单而实用的井眼净化模型,并以胜利油田8口大位移井的钻进参数为依据,验证了模型的准确性。
[Abstract]:Borehole cleaning technology is one of the key techniques in long reach drilling. It is very important to ensure hole cleaning for safe and fast drilling. During drilling, the debris particles are easily deposited to the lower side of the borehole to form a cuttings bed, and in the presence of the riser, the migration of the debris particles is susceptible to the marine low temperature and the annulus velocity. If the hole is not kept clean, it will cause a lot of problems, such as pump choking, drilling jam and so on, which will seriously affect drilling efficiency, drilling cost, wellbore quality and drilling safety, etc. The study of borehole purification technology is of great guiding significance for the rapid development of marine extended reach wells. In this paper, based on the investigation of relevant cuttings transport theory, the method of combining numerical simulation with theoretical research is adopted. The optimization of wellbore purification technology in marine extended reach drilling is studied. The influencing factors of cuttings movement in borehole annulus are simulated and analyzed by Fluent fluid dynamics software, and the influence degree of each factor is determined. This paper summarizes and induces the existing calculation model of borehole purification, aiming at its shortcomings, a set of simple and practical model of borehole purification is established, and the accuracy of the model is verified by an example. Based on the established model and Visual Basic 6.0 as the integrated development environment, the prediction and analysis software for wellbore purification effect is developed, and the rationality and accuracy of the software are verified. The results show that there is a critical value in annulus temperature. When the temperature is higher than this critical value, the volume concentration of annulus cuttings is almost unchanged, and the volume concentration of annulus cuttings decreases significantly with the increase of NK value of drilling fluid, which indicates that the carrying efficiency is more sensitive to the rheological parameters of drilling fluid, and among all the influencing factors, The influence of NK value of drilling fluid is the most, followed by annulus velocity, cuttings particle size and annulus temperature, while the influence of drilling fluid density and drill pipe rotation on cuttings migration law is relatively weak, and on the basis of existing calculation models, the calculation parameters are simplified. A set of simple and practical borehole purification model is established, and the accuracy of the model is verified by drilling parameters of 8 extended reach wells in Shengli Oilfield.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE52

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