Research and application of near-horizontal directional coring technology and supporting drilling tools

In order to solve the technical problems of accurate and fine geological exploration of mines and preliminary exploration of infrastructure projects, based on the deflection mechanism of rope coring straightening drilling trajectory, a combination of horizontal directional coring drilling straightening and tilt correction drilling tools, and a combination of directional rope coring drilling tools based on hollow screw were developed. Straightening and hole bottom correction drilling tools are used alternately in the process of near-horizontal coring drilling, and the trajectory measurement system can be used together with the combination of two drilling tools to achieve the effect of normal drilling straightening and hole bottom correction directional coring for hole oblique section; the directional rope coring drilling tool intends to use the “hollow screw + storage inclinometer” to realize the rope coring and the hole deviation measurement and correction at the same time, and the drilling direction extends along the set trajectory to form a drilling tool combination and method with continuous directional rope coring drilling function. The field test results show that the axial deviation of hole 1# at a depth of 325.1 m is controlled within 2 m, and it is feasible to carry out horizontal directional core drilling with the combination of hole straightening and deviation correction.