Blind drilling technology in wire-line core drilling

Abstract:

In 2020， 50 boreholes were drilled for limestone exploration in the Yandong Mountain area of Zhongning county by Geology and Mineral Exploration Academy of Ningxia. With presence of well developed fractures in limestone strata in this mining area， serious circulation loss problems were common， and total circulation loss was encountered in most of the boreholes， which resulted in two bit burning accidents in the early stage of drilling and increased drilling cost. In order to complete drilling tasks and save drilling cost， a blind drilling process was explored through addressing the borehole structure， bit selection， drilling parameters and pump rate optimization， where fresh water was used for drilling fluid with strict control of various drilling parameters. As a result， all drilling tasks were successfully completed with average rig-month efficiency of 883m， and average core recovery of 98%. The process has effectively improved drilling efficiency， and reduced drilling cost， providing strong resource support for local development.