考虑钻具屈曲的环空流动仿真研究

发布时间：2018-06-06 21:13

本文选题：偏心环空 + 正弦屈曲　；参考：《断块油气田》2017年05期

【摘要】：在小井眼定向井和水平井钻井过程中,钻具屈曲会对环空流场、压力场产生较大影响。文中借助流体动力学计算软件ANSYS FLUENT开展了考虑钻具正弦、螺旋屈曲的环空流动仿真模拟,系统地研究了不同环空偏心距、不同转速等因素对环空流场和流动压降的影响规律。研究发现:同心环空中,流体流速沿径向对称分布,偏心、屈曲环空中偏离对称分布;环空间隙越大,环空流速就越大;当考虑钻柱旋转时,钻柱旋转对环空窄间隙处流速的影响比对环空宽间隙处的影响要大,可明显提高环空窄间隙处的流速;同心环空、偏心环空压降值沿井深呈线性增加,偏心度越大,压降越小;屈曲环空压降值沿井深呈非线性增加,转速越大,压降越小。仿真结果与实验结果相比,具有较高的准确性,对真实钻井条件下环空压降的计算具有一定的指导意义。
[Abstract]:In the drilling process of small hole directional well and horizontal well, the buckling of drilling tool will have a great influence on annulus flow field and pressure field. In this paper, the simulation of annulus flow considering sinusoidal and spiral buckling of drilling tools is carried out with the help of ANSYS fluent, and the effects of different eccentricity of annulus and different rotational speed on annular flow field and flow pressure drop are systematically studied. It is found that the velocity of fluid in concentric annulus is symmetrically distributed along radial direction, eccentric, buckling annulus deviates from symmetrical distribution; the larger the annulus gap, the greater the annulus velocity; when the drill string rotation is considered, The influence of drill string rotation on the flow velocity in narrow annulus is greater than that at wide gap in annulus, and it can obviously increase the velocity at narrow gap in annulus, and the pressure drop of eccentric annulus increases linearly along the well depth in concentric annulus, the greater the eccentricity, the smaller the pressure drop. The buckling annulus pressure drop increases nonlinearly along the well depth, and the greater the rotation speed, the smaller the pressure drop. Compared with the experimental results, the simulation results have higher accuracy and have certain guiding significance for the calculation of annular pressure drop under real drilling conditions.
【作者单位】：西南石油大学油气藏地质及开发工程国家重点实验室;中国石化华东石油工程公司钻井处;
【基金】：国家自然科学基金项目“基于流-固-化耦合理论的欠平衡钻水平井井壁失稳机理研究”(51474186)、“基于多场耦合理论的页岩气水平井井壁失稳机理研究”(51574202) 国家科技重大专项专题“欠平衡钻井工艺技术研究”(2008ZX05045-03-07HZ)、“特殊结构井井眼稳定及摩阻控制技术”(2011ZX05045-03-01WX)
【分类号】：TE921.2

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