CAJ | 학술논문

顶替界面失稳指进造成的钻井液迟流是导致油气水窜槽的主要原因。水平井顶替界面受到套管偏心引起的宽窄间隙阻力效应和密度差引起的浮力效应共同影响，且两者对顶替界面的影响相反，因此有必要根据水平井套管偏心情况优化顶替流体密度差，从而提高顶替界面的稳定性。在总结三维数值模拟方法优缺点的基础上，采用该方法分析了水平井顶替界面长度随顶替时间的变化规律，以实现最小顶替界面长度为目标，得出了水平井套管偏心度与最优密度差之间的匹配关系。研究结果表明：水平井顶替界面长度随顶替时间增加增长幅度趋缓，但并不明显；在水平井套管偏心的情况下，密度差过大或过小都会降低顶替界面的稳定性，需要根据套管偏心度选取合理的密度差使得顶替界面长度最短。研究结果为水平井顶替参数和封固段长度设计提供了必要的理论依据。
정체계면실은지진조성적찬정액지류시도치유기수찬조적주요원인。수평정정체계면수도투관편심인기적관착간극조력효응화밀도차인기적부력효응공동영향，차량자대정체계면적영향상반，인차유필요근거수평정투관편심정황우화정체류체밀도차，종이제고정체계면적은정성。재총결삼유수치모의방법우결점적기출상，채용해방법분석료수평정정체계면장도수정체시간적변화규률，이실현최소정체계면장도위목표，득출료수평정투관편심도여최우밀도차지간적필배관계。연구결과표명：수평정정체계면장도수정체시간증가증장폭도추완，단병불명현；재수평정투관편심적정황하，밀도차과대혹과소도회강저정체계면적은정성，수요근거투관편심도선취합리적밀도차사득정체계면장도최단。연구결과위수평정정체삼수화봉고단장도설계제공료필요적이론의거。
Slow-lfow drilling lfuid caused by ifngering instability of displacement interface is the main factor to result in oil/gas/water channeling. The displacement interface in horizontal wells is affected by resistance effect in narrow and wide clearances caused by casing eccentricity and buoyancy effect caused by density difference. Besides, impacts of the two factors on displacement interface are opposite. Therefore, displacement interface stability can be enhanced by optimizing the density difference of displacing lfuids based on casing eccentricity in horizontal wells. The change law of the displacement interface length with time is analyzed based on the advan-tages and disadvantage of the method of three-dimensional numerical simulation to realize the target of minimum displacement interface length and have the matching relationship between the optimal density difference and casing eccentricity. The conclusions are as follows:the growth rate of displacement interface length slows down with time increasing, but it is not obvious; the too large or small density difference will reduce the displacement interface stability in the eccentric annulus of horizontal wells. In order to achieve the shortest displacement interface length in cementing, reasonable density difference shall be chosen on the basis of casing eccentricity. The study results provides theoretical basis for the design of displacement parameters and cementing length in horizontal wells.