工程测井在泥页岩井壁稳定评价中的应用

发布时间：2018-03-08 00:35

本文选题：泥页岩　切入点：井壁稳定　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：井壁失稳是在石油与天然气钻井过程中碰到的一个非常复杂的难题,由于井壁坍塌而造成井下事故,会给石油与天然气的勘探开发带来很大的经济损失。钻井过程中保持井壁的稳定性对于石油与天然气的开发具有非常重要的意义。在以往的井壁稳定性研究中,大多是通过钻井取心进行室内实验的方法进行的,这种方法虽然精度较高,但由于连续性差,成本高等原因使得应用受到限制。工程测井能够提供大量的井下地层连续性信息。本文借助少量室内试验,应用测井数据对泥页岩地层井壁稳定性进行分析和评价。本文取得的成果和认识如下:(1)实验开展了泥页岩矿物组成、粘土矿物组分、阳离子交换容量以及比表面积测试,同时利用现场自然伽马能谱测井资料对泥页岩地层粘土矿物组分和含量以及泥页岩理化性质进行了综合评价。评价结果表明研究区黏土矿物含量高,地层泥页岩水化膨胀性较强。(2)借助三轴岩石力学实验仪和常规测井资料对泥页岩井周应力场及岩石力学性质进行了分析。(3)根据水溶液在近井壁地层中的运移规律,结合泥页岩渗流基本方程,分析了渗流场对于地层孔隙压力及井壁稳定的影响,地层孔隙压力在渗流作用的影响下随着时间的增加而增大,随着距离的增加而减小。(4)借助室内Zeta电位测试实验,评价了不同离子类型和离子浓度条件下膨胀性粘土矿物表面电位的变化情况,结合扩散双电层理论,探索性提出了水化应力的评价模型。利用现场测井数据计算了水化应力,水化应力会对井周有效应力产生重要影响,进而影响井壁稳定性。(5)在井壁稳定性传统力学评价的基础上,分析了泥页岩水化膨胀应力对地层压力和力学强度的影响。将渗流场和水化作用耦合进泥页岩井壁稳定性评价当中,得到渗流效应及水化应力影响下的“安全密度窗口”。通过以上研究内容,对研究区井壁稳定进行了综合评价,所采用的评价方法对研究区适用性较好,能为现场钻井液设计提供指导意义。
[Abstract]:Wellbore instability is a very complicated problem encountered in the course of oil and natural gas drilling, and the downhole accident is caused by the wellbore collapse. It will bring great economic loss to the exploration and development of oil and natural gas. It is very important for the exploitation of oil and natural gas to maintain the stability of wellbore during drilling. Most of them are carried out by drilling and coring for laboratory experiments. Although the accuracy of this method is high, but because of the poor continuity, The application is limited because of the high cost. Engineering logging can provide a large amount of underground formation continuity information. Using logging data to analyze and evaluate the wellbore stability of shale formation. The results and understandings obtained in this paper are as follows: 1) the shale mineral composition, clay mineral composition, cation exchange capacity and specific surface area are tested in this paper. At the same time, the composition and content of clay minerals in shale formation and the physical and chemical properties of shale are comprehensively evaluated by using field natural gamma spectrum logging data. The evaluation results show that the clay mineral content in the study area is high. The stress field around shale well and rock mechanical properties are analyzed by means of triaxial rock mechanics experiment instrument and conventional logging data.) according to the migration law of aqueous solution in the near wellbore formation, the stress field and rock mechanics property of shale well are analyzed by means of triaxial rock mechanics experiment instrument and conventional logging data. Combined with the basic equation of shale percolation, the influence of percolation field on formation pore pressure and wellbore stability is analyzed. Under the influence of percolation, the formation pore pressure increases with the increase of time. With the increase of distance, the change of surface potential of expansive clay minerals under different ion types and ion concentrations was evaluated by means of laboratory Zeta potential measurement experiments, and the diffusion double layer theory was combined. The evaluation model of hydration stress is put forward. The hydration stress is calculated by using field logging data. The hydration stress will have an important effect on the effective stress around the well. On the basis of traditional mechanical evaluation of wellbore stability, The influence of hydration expansion stress on formation pressure and mechanical strength is analyzed. The "safe density window" under the influence of seepage effect and hydration stress is obtained. Through the above research contents, the stability of shaft lining in the study area is comprehensively evaluated, and the evaluation method adopted is suitable for the study area. It can provide guidance for field drilling fluid design.
【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】：TE21

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