Core drilling technology for shallow brine mine in a salt lake in Qinghai Province

Abstract:

The shallow overburden of salt lake has the characteristics of strong water solubility， poor cementation， developed fractures and pores， etc. Boreholes are prone to problems such as diameter shrinkage， collapse， corrosion peeling， leakage， etc.， which further leads to borehole accidents such as tool stuck， drill buried， pump suppression， etc. Therefore， it is necessary to improve drilling technology to promote the quality and efficiency of engineering construction. Combined with the actual situation in the mining area， the project explored the combined wire-line core drilling technology of “short drilling tool+side-sprayed PDC bit+saturated brine flushing fluid+PVC tube protection wall”， by carrying out experimental research， optimizing the drilling parameters， improving the saturated brine flushing solution ， preferably selecting the core bit， modifiying the wire-line coring winch according to local conditions， designing and developing the single-double action joint of layered pumping test device， these technical measures were successfully applied in shallow drilling construction and production of salt lake， which ensures the high-quality and efficient implementation of drilling engineering.

Key words:brine mine;wire-line coring;PDC bit;saturated brine flushing fluid;salt lake