致密砂岩油藏水平井摩阻扭矩预测模型研究

发布时间：2018-09-17 07:28

【摘要】：随着常规油气资源日益减少,致密砂岩油藏成为油气勘探开发的新热点。与常规油藏水平井相比,致密砂岩油藏水平井具有水平位移长、摩阻扭矩大等特点,导致井眼轨迹比较复杂,这些因素都决定了致密砂岩油藏水平井在钻井过程中受力比较复杂,经常出现钻柱在井眼内弯曲,严重时甚至出现自锁现象。因此通过理论模型对致密砂岩水平井钻柱摩阻扭矩计算预测,具有非常重要的意义。本文首先对致密砂岩油藏进行地质特征研究的基础上,考虑井眼轨迹参数、钻井液粘性阻力和钻柱屈曲的影响等因素分别建立了钻柱摩阻扭矩的软杆模型和硬杆模型。针对致密砂岩油藏水平井钻井时钻柱形状与井眼形状不一致的现象,采用离散化方法以每个接头作为节点进行分析,利用三次样条插值法对井眼轨迹进行拟合,建立致密砂岩油藏水平井摩阻扭矩计算模型,并通过MATLAB软件编制了新的摩阻扭矩模型的数值计算算法,优化了数值计算的复杂性与计算时间。最后,在现场实例的基础上,分别使用LANDMARK软件和离散化模型对研究区的一口井进行了分析计算,通过计算对比分析可以得出新的离散化模型的精确度更高,验证了致密砂岩油藏水平井摩阻扭矩预测模型的合理性、准确性,为现场工程实践提供必要的技术支持。
[Abstract]:With the decrease of conventional oil and gas resources, tight sandstone reservoir has become a new hot spot in oil and gas exploration and development. Compared with horizontal wells in conventional reservoirs, horizontal wells in tight sandstone reservoirs are characterized by long horizontal displacement and large friction torque, resulting in a more complex wellbore trajectory. These factors all determine that the stress of horizontal wells in tight sandstone reservoirs is complex during drilling, and the drill string is often bent in the hole, and even self-locking phenomenon occurs in serious cases. Therefore, it is of great significance to predict the friction torque of drill string in tight sandstone horizontal well by theoretical model. Based on the study of the geological characteristics of tight sandstone reservoir, the soft pipe model and the hard pipe model of the friction torque of drill string are established by considering the well trajectory parameters, the influence of the viscosity resistance of drilling fluid and the buckling of drill string, etc. Aiming at the phenomenon that the drill string shape is not consistent with the borehole shape during horizontal drilling in tight sandstone reservoir, each joint is analyzed by discrete method, and the borehole trajectory is fitted by cubic spline interpolation method. The calculation model of frictional torque of horizontal well in tight sandstone reservoir is established, and a new calculation algorithm of frictional torque model is compiled by MATLAB software, which optimizes the complexity and calculation time of numerical calculation. Finally, on the basis of field examples, LANDMARK software and discrete model are used to analyze and calculate a well in the study area, and the accuracy of the new discretization model is higher than that of other models. The rationality and accuracy of friction torque prediction model of horizontal well in tight sandstone reservoir are verified, which provides necessary technical support for field engineering practice.
【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】：TE243

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