CAJ | 학술논문

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。
선전투관고정가이개변정체과정중류체적류장，증가주향적선류화회류작용，경호지보장정체계면은정성，제고고정정체효솔。차조계산류체역학연건대대위이정선전투관고정정체진행수치모의，병득도불동정사각화정경확대솔조건하적최저투관선전전속。결과표명：동일투관선전속도，절향속도수착무량강배공반경적증가이강저，수착정사각적증가，절면선류수재불동위치처각이，단총체추우감소，투관선전고정정체효솔명현개선，정사각월대，개선효과월호；편심도월대，배공동일위치처선류수월대，착간극적선류수명현고우관간극적선류수，재편심도대우0．4이후，정체효솔증가효과명현；배공절면동일위치처，정경확대솔월대，기산생적선류수월대，선류정도증강，유리우수니장고정정체；채용선전투관고정능유효개선복잡정안조건하대위이정고정정체질량화정체효솔。
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 efficien-cy. The rotating-casing cementing displacement in extended reach well was simulated by computational fluid dynamics soft-ware, 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 slur-ry 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.