Design and Experimental Study of an Ultra-Long Drill Pipe Transfer System for Efficient Continuous Operations in Resource Development

In the context of sustainable development, high-efficiency drilling operations have become a key objective in advancing scientific drilling technology. Given the frequent coring and tripping operations involved in ultra-deep scientific drilling, automating and streamlining the make-up/breakout and handling/transfer of drill pipe wellhead tools is a critical technological pathway for improving overall drilling efficiency. To meet the demand for faster tripping operations, this study designed a high-efficiency transfer system for ultra-long drill pipe and determined its optimal operating strategy by combining experiments with finite element analysis. All experiments were conducted on a dedicated intelligent drilling platform. For three drill pipe sizes (3.5 in, 4.5 in, and 5 in), a series of tests were performed, including four-stand lifting tests, asynchronous up/down transfer tests, and inclined lean-against tests. The results indicate that the maximum bending deformation occurs within 16–21 m above the wellhead, with a peak deflection of 549 mm. Based on these findings, four-stand drill pipe are best transferred using an integrated “lower support + upper clamp” mode, whereas drill collars are better handled using a push-and-support mode. Subsequently, aiming to achieve 25 stands per hour during tripping operations, a corresponding tripping workflow and an offline operational scheme were developed. Finally, an integrated control strategy for the transfer system was proposed, considering the overall rig layout and tubular-handling process requirements. Through systematic design, experimental validation, and process optimization, this study has developed an efficient handling method and integrated control scheme for ultra-long drill pipe during drilling and tripping operations in ultra-deep scientific drilling. The findings provide technical and equipment support for the sustainable development and efficient utilization of resources.