Geophysical And Dth Bits Of Rock Fragmentation Mechanism, Kinetics And Structural Improvements

In this paper, the relating theory on the problem of physics exploration bit are researched from the aspects of the failure analysis, rock fragmentation mechanism , impact system dynamics, mechanics analysis on the button, improvement of breed for bit etc respectively aimed at the serious dissipation and improper use of the DTH bit(down-the-hole bit) in the field application presently, based on gathering and analyzing information about the bit and percussion-rotary drilling technique at home and abroad, in order to supply theoretic foundation for structural design of the DTH bit and improvement drilling technique. The whole contents are shown in the following text:(1) Failure analysis on physics exploration bit. Combining operating mode, failure mechanism in every part of physics exploration bit is analyzed, and failure reason is researched in order to offering reference of physical design and machining technology of the bit.(2) Rock fragmentation mechanism analysis. Using LS-DYNA, the explicit dynamic finite element software, the rock fragmentation processes of different button are simulated. Rock fragmentation mechanism under impulsive load and the major factors affecting rock fragmentation efficiency are studied combining the relating theory about fracture mechanics, damnification mechanics and penetration mechanics. All of these offer theory guidance for the button shape selection and determination relating drilling parameter.(3) Dynamics study on physics exploration percussive system. System dynamics equation are founded by wave mechanics and fragmentation energy theory. The relation among drill tool of impact system, rock and drill technical parameter etc is discovered, and models of rock resistance and the interaction of bit-rock are explored. The aim is to describe rock fragmentation process and to confirm reasonable structure parameter of bit and drilling technical parameter more.(4) The mechanics analysis and marginal button obliquity design on the button of physics exploration bit. The mechanics analysis and impact fatigue age ofmiddle button and marginal button are researched. Then the confirming methods of the structure parameter of the button and marginal button obliquity are given, and calculating formation are confirmed.(5) The improved design for the major structural parameter and machining technics of physics exploration bit. Based on the former returns and design experience, the following aspects are ameliorated, including the top shape, vent hole, slag runner, spline, button shape, button distribution etc. Then the three-dimensional solid model of physics exploration bit after amelioration is confirmed.