水平井波动压力计算理论建模及软件开发

发布时间：2018-04-05 22:19

本文选题：水平井　切入点：偏心环空　出处：《西安石油大学》2017年硕士论文

【摘要】：在窄环空间隙中下套管、小井眼钻进、深水钻进和长水平段水平井钻进等作业中,精确的波动压力计算模型是准确预测井底压力,避免井涌、井漏、井壁失稳等井下复杂情况发生的前提。现场常用的波动压力预测模型如Burkhardt模型和Schuh模型是针对于同心环空而建立的,而在水平井的斜井段和水平段,受重力因素和岩屑床的影响,会导致管柱在环空中处于偏心的位置。偏心环空和同心环空中波动压力的计算方法不同,采用传统的波动压力计算方法会使得对于水平井井底波动压力的预测偏大。针对以上问题,本文建立了适用于水平井的稳态和瞬态波动压力计算模型。本文首先从影响波动压力计算的因素出发,分析了在水平井的水平段偏心度对波动压力的影响;提出了钻井液流变参数拟合与流变模式优选的改进的黄金分割算法;分析了不同的钻柱工作状况下环空中流体的速度分布;并分析了钻杆接头、钻井液的静切力以及管柱加速度对波动压力的影响。其次,针对水平井井筒中流体的稳态和瞬态流动状态,分别建立了波动压力的计算模型,在模型建立的过程中,考虑了不同的偏心度、钻井液流变模式和管柱工作状况。对模型的合理性进行了验证,其中,4参数流体分别在同心环空中和偏心环空中流动的稳态波动压力计算模型的计算结果和前人测量的多组实验数据的误差基本都在10%以内;瞬态波动压力模型计算结果同Burkhardt和Clark各自测量的两口井的现场测量数据的最大误差分别为11.5%和9.93%。最后,根据所建立的水平井中波动压力计算模型,利用Matlab语言编制了波动压力计算软件,并通过实例计算对波动压力计算模型的参数敏感性进行了分析。分析结果表明:井底波动压力随着偏心度的增加而降低,完全偏心时可降低50%左右;波动压力随着造斜点深度、管柱运行深度、管柱运行速度和加速度等参数的增加而增加;下钻时,井底波动压力随泵排量的增加而增加;起钻时,井底抽汲压力随泵排量的增加而减小。在现场钻井作业中应充分考虑这些因素对波动压力的影响,最终将起下钻速度限定在软件计算出来的最大起下钻速度之内。
[Abstract]:In the operations such as casing drilling in narrow annular gap, small hole drilling, deep water drilling and horizontal well drilling in long horizontal section, the accurate calculation model of fluctuation pressure is to accurately predict bottom hole pressure and avoid wellbore and well leakage.The premise of the occurrence of complex downhole conditions such as wellbore instability.The commonly used wave pressure prediction models, such as Burkhardt model and Schuh model, are established for concentric annulus, but in the horizontal and inclined sections of horizontal wells, they are affected by gravity factors and cuttings bed.It can cause the string to be eccentric in the annulus.The calculation methods of wave pressure in eccentric annulus and concentric annulus are different.Aiming at the above problems, a steady and transient wave pressure calculation model for horizontal wells is established in this paper.In this paper, the influence of eccentricity on wave pressure in horizontal section of horizontal well is analyzed, and an improved golden section algorithm for fitting rheological parameters of drilling fluid and optimal selection of rheological model is proposed.The velocity distribution of annular fluid in different drill string working conditions is analyzed, and the influence of drill pipe joint, static shear force of drilling fluid and string acceleration on fluctuating pressure is analyzed.Secondly, according to the steady state and transient flow state of fluid in horizontal well, the calculation models of fluctuating pressure are established, and different eccentricity, rheological mode of drilling fluid and working condition of pipe string are considered in the process of establishing the model.The rationality of the model is verified. The calculation results of steady wave pressure of the flow in concentric annulus and eccentric annulus respectively and the error of many groups of experimental data measured by predecessors are within 10%.The maximum error between the transient wave pressure model and two wells measured by Burkhardt and Clark is 11.5% and 9.93% respectively.Finally, according to the established calculation model of wave pressure in horizontal wells, the calculation software of wave pressure is compiled by using Matlab language, and the sensitivity of parameter of wave pressure calculation model is analyzed by example calculation.The results show that the downhole wave pressure decreases with the increase of eccentricity, and decreases by about 50% at complete eccentricity, and the fluctuating pressure increases with the increase of the depth of diagonal point, the operating depth of string, the running speed and acceleration of string, etc.During drilling, the bottom hole fluctuation pressure increases with the increase of pump displacement, while the bottom hole swabbing pressure decreases with the increase of pump displacement.The influence of these factors on the fluctuating pressure should be fully considered in the field drilling operation, and finally the down-drilling speed should be limited to the maximum down-drilling speed calculated by the software.
【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】：TP311.52;TE21

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