Double tube single action core drilling tool

Abstract

The invention belongs to a drilling tool, and specifically discloses a double-tube single-action core drilling tool. The lip surface of the drill bit is stepped from the inner ring to the outer ring along its radial direction, and the rest of the lip surface of the drill bit is tapered. ; The axis of the water eye and the drill bit intersects in the inner cavity of the drill bit; the connecting end of the cross mandrel and the water distribution joint is provided with a ball-throwing check valve. The bottom lip surface of the drill bit of the present invention adopts a stepped tapered structure, which has a pressing effect on the larger gravel towards the hole wall, avoids the wear and tear of the core by the larger gravel, and has good rotation stability and guiding performance of the drilling tool. It is beneficial to protect the core and prevent the hole from being inclined; after the ball-throwing check valve throws the ball, the flushing fluid flows from the drill pipe through the gap between the inner and outer pipes to the water hole of the side-spray drill bit and then flows to the bottom of the hole, avoiding the impact of the liquid flow on the core in the pipe Direct erosion; the average recovery rate of rock core is increased from 40.30% to 91%, and the high-quality porosity is increased from 17.40% to more than 90%, which meets the requirements of geological prospecting.

Description

Double-tube single-action core drilling tool technical field [0001] The invention belongs to drilling tools, in particular to a double-tube single-action drilling tool. Background technique The crisp sandstone in Yili Basin mainly refers to the middle and lower Jurassic medium-coarse sandstone, pebble-containing sandstone and glutenite, and uranium The interlayer oxidation zone closely related to mineralization develops in it, which is the main target layer of geological prospecting. The sand body structure is loose, in the shape of "bean curd residue", the mud is weakly cemented or has no cementation, and the main components are quartz, feldspar and rock Crumbs, gravel diameter 10-250mm gravel content up to 60-70%. When core drilling in this formation, the core is subjected to external force (mechanical action or liquid action), its natural structure is easily destroyed, and it is easily eroded by the flushing fluid and "dissolved" in the flushing fluid. The heart ...

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Problems solved by technology

The core recovery rate is lower than 50%, it is difficult to obtain qualified rock cores th

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