CO_(2)密闭混砂装置清砂参数优化及现场试验

Optimization of sand cleaning parameters and field test of CO_(2) closed sand mixing device

为了促进CO_(2)干法加砂压裂技术的配套与推广应用,针对CO_(2)干法加砂压裂施工结束后,核心装备CO_(2)密闭混砂装置罐体内剩余陶粒砂清理困难,清理效率低下,清理过程存在安全风险的问题,开展了清砂方式改进、风送清砂装置研制以及清砂参数优化等方面的研究工作,并进行现场试验。结果表明:1)自动化清砂方案通过设计气驱与输砂螺旋结合的清砂流程,配合专门研制的风送清砂装置,相比负压清砂方案,清砂速度提高了225%,纯清砂速度提高了165%;2)自动化清砂方案可实现人不进罐清砂,将陶粒砂直接输送至砂罐车,通过CO_(2)密闭混砂装置远程控制清砂过程及参数,清砂工作条件大大改善,符合安全化生产要求;3)大大减小清砂劳动强度,无需拆装人孔法兰,清砂人数由之前的4~6人减少至2人;4)优选出最佳清砂参数,即输砂螺旋转速为45 r/min,补压阀开度为25%,风送清砂装置为2档位。以上成果认识,对CO_(2)干法加砂压裂施工完成后的罐体高效清砂作业具有一定的指导意义。

In order to promote the matching,promotion and application of CO_(2) dry sand fracturing technology,research work has been carried out on the improvement of sand-cleaning method,the development of air-driven sand-cleaning device,and the optimization of sand-cleaning parameters,aiming at the problems of the difficulty in cleaning the residual ceramsite sand in the tank of the CO_(2) closed sand mixing device,the low cleaning efficiency,and the safety risks in the cleaning process after the completion of CO_(2) dry sand fracturing construction,and conduct field test.The results show that:1)Compared with the negative pressure sand-cleaning scheme,the automatic sand-cleaning scheme increases the sand-cleaning speed by 225%and the pure sand-cleaning speed by 165%through the design of the sand-cleaning process combining gas drive and sand-transferring spiral and the specially developed air-driven sand-cleaning device;2)The automatic sand-cleaning scheme can realize the sand-cleaning without entering the tank,directly transport the ceramsite sand to the sand tank truck,remotely control the sand-cleaning process and parameters through the CO_(2) closed sand mixing device,greatly improve the sand-cleaning working conditions,and meet the requirements of safe production;3)The labor intensity of sand cleaning is greatly reduced,and there is no need to disassemble the manhole flange.The number of sand cleaning personnel is reduced from 4 to 6 to 2;4)The best sand cleaning parameters are selected,that is,the rotating speed of the sand conveying screw is 45 r/min,the opening of the pressure compensating valve is 25%,and the pneumatic sand cleaning device is in gear 2.The above achievements have certain guiding significance for the efficient sand cleaning operation of the tank after the completion of CO_(2) dry sand fracturing construction.