水平井岩屑床止动模型的建立

在水平井钻井中，洗井区的携岩状况关系到整口井钻探的成败。利用大斜度井及水平井环空携岩的理论研究成果，根据岩屑床在环形空间的受力分析建立了第二洗井区岩屑床止动模型，提出了环空止动返速和环空止动排量的概念，并推导了钻井液在环空中处于幂律流型、宾汉流型和修正幂律流型时相应的环空止动返速的计算公式，运用该模型对胜利油田、大庆油田、中原油田和大港油田所钻的九口水平井的部分资料进行了处理，结果表明，目前实钻水平井因携岩问题出现的复杂现象，根本原因在于实际环空返速低于环空止动返速。得到了目前我国大斜度井及水平井第二洗井区环空止动返速的统计性数据，并且提出了改善第二和第三洗井区环空携岩状况的一般方法。

ESTABLISMENT OF UNSLIDED CUTTINGS BED MODEL IN HORIZONTAL WELL DRILLING

In horizontal well drilling,the cuttings transport is very important.A modelfor cutting bed on the second hole cleaning region is established according to the mechanicalanalysis of cuttings bed in annular.A concept of annular unslided velocity and annularunslided displacement is introduced. The calculated formula of annular velocity is deductedwhen drilling fluid is correspond to the Power-Law fluid, Binhan fluid and modifiedPower-Law fluid. Partial materials from nine wells of Shengli, Daqing and Zhongyuanoilfields were handled with this model. The problems, of cuttings transport in the currenthorizontal well drilling resulted from that real annular velocity is smaller than unslidedannular velocity. So the statistical data of annular unslided velocity on the second holecleaning region of big inclined and horizontal wells of our country were obtained. Generalmethods for improving the conditions of the second and the third hole cleaning regions werepresented.