大斜度井环空岩屑床厚度评价技术及其应用

大斜度井段和水平井段极易在钻井过程中形成岩屑床，为解决定向井井眼净化问题，在考虑钻杆旋转、钻井液性能和岩屑颗粒尺寸等多种因素的基础上，推导出了一套适合大斜度井、水平井的无岩屑沉降的环空临界返速模型。在此基础上，修正了环空岩屑床厚度评价模型。利用该模型对冀东柳103-平1井环空岩屑床厚度进行了评价。结果表明，该井在井斜角为66°左右时岩屑床厚度达到了最大，但没有达到发生复杂事故临界点。实践表明：该方法可为现场工程师在大斜度井段和水平井段水力参数的设计提供指导，能有效避免钻井复杂事故。

RESEARCH AND APPLICATION OF ANNULAR CUTTINGS BED THICKNESS EVALUATION MODEL FOR HIGH ANGLE WELLBORES INCLUDING HORIZONTAL WELLS

Cuttings bed is easily formed during drilling in high angle wellbores including horizontal wells. In order to solve the problem of hole cleaning for directional wells, this paper deduces an annular return velocity critical evaluation model applicable for high angle wellbores including horizontal wells. The model takes into account the rotating drilling rod, performance of drilling fluid, size of cutting grain ect. The cutting bed thickness in the well Liu103-Ping1 of the Jidong oil field was evaluated by using the model. The results show that the thickness of cuttings bed reaches the maximum when the deviation angle is around 66° but does not reach the critical point for the accident occurrence. The field practices demonstrate that this method will provide reference for engineers to determine hydraulic parameters to achieve accident free drilling in high angle wellbores including horizontal wells.