Design and Experimental Study of Negative Pressure Spiral Separation and Reduction Device for Drilling Holes

Currently, screw conveyors and negative pressure vacuum screens with negative pressure vibration units are used for handling drilling cuttings both domestically and internationally. However, there is currently no effective solution to address the high liquid content of drilling cuttings during their conveyance by screw conveyors. In this paper, a novel design scheme for a negative pressure spiral separation and reduction device is proposed based on an extensive literature survey. This device aims to effectively reduce the liquid content of drilling cuttings during their conveyance by screw conveyors, thereby minimizing the overall liquid content throughout the drilling process. The structural design of the negative pressure spiral separation and reduction device is conducted using theoretical analysis and 3D solid modeling methods, while strength analysis of the negative pressure suction unit is performed using a finite element method. Additionally, theoretical research on relevant process parameters is carried out, and an online real-time testing system for experiments is designed. An analysis of experimental results demonstrates that within 151 s, the liquid suction rate of the device can reach 51%, with an average flow speed of approximately 0.008 m/s, thus achieving the desired target for drilling cutting separation and reduction. By designing this new negative pressure spiral separation and reduction device, its feasibility has been verified through acceptable engineering results obtained from experimentation; furthermore, it aims to achieve an optimal liquid suction effect for drilling cuttings in order to enhance solid–liquid separation efficiency, as well as to improve drilling fluid recovery efficiency by conserving mud materials and reducing overall drilling costs.