水平井段环空携岩的实验研究

EXPERIMENTAL STUDY OF CUTTINGS-CARRYING IN HORIZONTAL WELL

用室内实验的方法对水平井段偏心环空中的岩屑携带问题进行了研究.着重探讨了环空返速、钻井液流变性能及钻柱偏心度等参数对携岩效果的影响.结果表明,在钻进过程中,水平井段形成岩屑床是难以避免的.环空返速及钻井液的流变参数增大,可降低环空内岩屑的总浓度.偏心度增加,会使环空内清洁程度变差.不同流体的携岩效果也不同.聚丙烯酰胺水溶液的携岩效果较好,清水的携岩效果最差.改善钻井液流变性能及加强水力清洗是解决水平井段环空携岩问题的两个重要途径.

An experiment on the cuttings-carrying in the eccentrical annul us of the horizontal section of a horizontal well was conducted in laboratory. Some factors affected cuttings-carrying capacity, such as annular velocity, drilling fluid rheology and eccentricity of drill string. The results showed that formation of cuttings bed on the low side of the horizontal section is unavoidable during drilling. An increase of eccentricity of drilling string made cuttings carrying more difficult. Three drilling fluids with different carrying capacities were tested. The tests showed that PAM water solution is the best, while fresh water is the worst. Improvement of fluid rheology and enhancement of hydraulic cleaning are the two important methods to solve the problem of cuttings transport in a horizontal well.