摘要: |
旋转套管固井可以改变顶替过程中流体的流场,增加周向的旋流和回流作用,更好地保障顶替界面稳定性,提高固井顶替效率。借助计算流体力学软件对大位移井旋转套管固井顶替进行数值模拟,并得到不同井斜角和井径扩大率条件下的最低套管旋转转速。结果表明:同一套管旋转速度,切向速度随着无量纲环空半径的增加而降低,随着井斜角的增加,截面旋流数在不同位置处各异,但总体趋于减小,套管旋转固井顶替效率明显改善,井斜角越大,改善效果越好;偏心度越大,环空同一位置处旋流数越大,窄间隙的旋流数明显高于宽间隙的旋流数,在偏心度大于0.4以后,顶替效率增加效果明显;环空截面同一位置处,井径扩大率越大,其产生的旋流数越大,旋流程度增强,有利于水泥浆固井顶替;采用旋转套管固井能有效改善复杂井眼条件下大位移井固井顶替质量和顶替效率。 |
关键词: 大位移井 旋转套管 旋流强度 顶替效率 数值模拟 |
DOI:10.3969/j.issn.1673-5005.2015.03.012 |
分类号::TE 931.2 |
基金项目:国家“863”计划项目(2012AA091501);中央高校基本科研业务费专项(15CX06020A);教育部长江学者和创新团队发展计划(IRT1086) |
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Simulation analysis of rotating-casing cementing displacement in extended reach well |
WANG Jintang1, SUN Baojiang1, LI Hao1, CAO Chengzhang2, PENG Zhigang2, XU Kewang1
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(1.School of Petroleum Engineering in China University of Petroleum, Qingdao 266580, China;2. Institute of Drilling Technology, SINOPEC Shengli Oilfield Service Corporation, Dongying 257017, China)
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Abstract: |
Rotating-casing cementing can alter the fluid flow field in displacement process and increase circumferential effect of whirl and reflux, which assure the better stability of the displacement interface and improvement of displacement efficiency. The rotating-casing cementing displacement in extended reach well was simulated by computational fluid dynamics software, through which the different deviation angles and the lowest casing rotation speed at the hole-diameter enlargement rate were obtained. The results demonstrate that the tangential velocity is reduced with the increase of the dimensionless radius of annulus at the same casing rotation speed. And as the deviation angle increase, the swirl numbers are different and generally tended to be declined in the flow sections. The displacement efficiency of rotating-casing cementing is improved significantly, and the larger the drift angle, the better the effect of improvement. Also, the greater eccentricity results in the larger swirl number in the same section. The swirl number in narrow is distinct larger than that in wide gap. When the eccentricity is greater than 0.4, the displacement efficiency increases significantly. At the same annular section, the bigger hole-diameter enlargement rate causes the larger swirl number, and the degree of rotational flow is enhanced, which is favorable to the slurry cementing displacement. Rotating-casing cementing has a great improvement of well-cementing quality and displacement efficiency in extended reach well under the bad hole conditions. |
Key words: extended reach well rotating casing swirling intensity displacement efficiency numerical simulation |