Application and Optimization technology of rope core drilling bit in potassium salt exploration:Taking JG-2 well as an example
JG-2 well is a geological survey well arranged by the Institute of Mineral Resources of the Chinese Academy of Geological Sciences in the Jinggu Depression Basin to further identify the potassium salt resources of the Mengye Well Formation in the Simao Basin.The designed well depth is 1800 m.The full hole coring technol-ogy adopts diamond and PDC rope coring techniques respectively.During construction,there are frequent and repeated alternations of rock salt,mudstone,sandstone,and mudstone conglomerates,resulting in rapid changes in rock drillability and abrasiveness.The mechanical drilling speed of the drill bit is uneven,and the mud package and rock core are severely worn,which brings great difficulties to the selection of the drill bit and affects drilling efficiency.This article analyzes and summarizes the lithological characteristics of the encountered strata,as well as the types and structures of drill bits used.After that,the eight blade PDC rope coring drill bit type was selected,and the structure and drilling parameters of the impregnated diamond drill bit were optimized to improve the rheological and cleaning properties of the mud,effectively solving the above problems and improving the efficiency and quality of the drill bit and coring.The final depth of the final hole was 1829.44 m,with a final diameter of 133mm.High quality rock salt cores with a diameter of≥78 mm were drilled,and the average recovery rate of the rock and ore cores reached 97.51%.This provides a certain reference for similar geological conditions of potassium salt investigation and drilling engineering.
potassium salt surveymud and gravel rock saltfrequent interlayer of rock layersapplication and optimization of drill bitslarge oblique tooth diamond drill bit
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