Study On Downhole Cuttings Bed Cleaning Tools For Extended-reach Drilling In YT25-1S Oil Field

Extended-reach drilling technique has been more and more useful in the oil exploration and development filed.The hole cleaning problems has been threatening the drilling and application of extended-reach wells.There are many well-hole cleaning techniques,including improving the drilling fluid properties,adjusting the drilling parameters,using the short trip &rotary reaming technology,and using the cuttings bed cleaning tools.But using the cuttings bed cleaning tools is the most economic and efficient.In this paper,study in the three types of cuttings-bed-cleaners concluded that helical blade is more advantageous to the removal of the cuttings bed.Using ANSYS analysis the cuttings-bed-cleaner's intensity and its flow field in annulus.Using the indoor experiment studied the relationship between the orthogonal helical blade angle,short day length,with the cuttings bed and drilling fluid velocity.The optimization design is: A single spiral structure tool suggested take spiral angle for 25° ~ 35°;The front of compound spiral structure is recommended to use 15° ~ 25° spiral angle,at the back of the recommended 40°~ 50° spiral angle;0.75 m ~ 1 m in length,diameter of 177.8mm,so that it can satisfy the cuttings bed removing tool with rock effect,and control of the construction process of downhole friction effect.In the end of the paper gives the calculation method of the using number and location.And obtain good application effect.