Experimental investigation of the annular cross-sectional distribution of cuttings bed with drillpipe rotation in horizontal wells

The cuttings bed height is crucial for assessing hole cleaning but assumes symmetry, which is not accurate during drillpipe rotation. A laser measurement method is used to investigate the cuttings bed cross-section. 71 tests in horizontal wells under rotary drilling conditions were conducted, revealing six types of cuttings bed crosssectional distribution. By investigating the effects of drillpipe rotation speed, flow rate, and wellbore inclination on the wetted perimeters and dip angles of cuttings bed surface in three fluids, the flow pattern diagrams are established and the asymmetric cuttings bed area is calculated. The observed characteristics simplified flow patterns into four groups. Using these groups with the multiple linear regression method, a correlation predicting the wetted perimeters and dip angles was established, with an accuracy exceeding 80%. These findings are vital for improving drilling operations and minimizing field risks by providing insights into drillpipe rotation's impact on cuttings bed.