Based on a model with three-degree-of-freedom, the nonlinear coupled axial-torsional vibration of drill string is numerically studied considering modified contact bit-rock interaction. The effects driving angular velocities, nominal drilling pressures, and formation stiffness response are discussed. simulation results show that can be periodic, quasi-periodic or chaotic motion variation system ...

Bent-housing motor is the most widely used directional drilling tool, but it often encounters problem of high friction when sliding in horizontal wells. In this paper, a mathematical model proposed to simulate slide with reduction tool axial vibration. A term called dynamic effective tractoring force (DETF) defined and evaluate effectiveness. The factors influencing DETF are studied, placement ...

Efficiency analysis of sonic drilling wells and the choice rational operational modes drill bit vibration loading to increase rate penetration was carried out. The are studied on basis an assessment power process with a cavitation hydrovibrator. This paper presents approach calculating mechanical oscillatory bit. uses developed mathematical model dynamics hydraulic vibrator string. describes in...

The pick is the working part of coal plow, cutting performance very important for efficient production mine. In order to analyze dynamic characteristics plow during process, a test platform was built. force and vibration head were obtained through test, relationship between speed depth analyzed. study influence different alloy shapes on pick, two kinds designed: with chip bit conical bit. finit...

this paper seeks to document the specific structural patterns of bit hilanis architecture which were in used in the ancient near east from the second to the first millennium b.c. the recognition of bit hilanis architectural characteristics as well as their provenances and their spread from anatoly to palestine have always remained the important issues to be addressed by art historians and archa...

Stick-slip vibration reduces the drilling rate of penetration, causes early wear bits, and threatens safety downhole tools. Therefore, it is necessary to study suppression methods stick-slip achieve efficient safe drilling. Field tests show that use axial impactors helpful mitigate improve rock-breaking efficiency. However, there are many deficiencies in how impact load affects a PDC bit. In th...

This paper studies the dynamical response of a rotary drilling system with a drag bit, using a lumped parameter model that takes into consideration the axial and torsional vibration modes of the bit. These vibrations are coupled through a bit-rock interaction law. At the bit-rock interface, the cutting process introduces a state-dependent delay, while the frictional process is responsible for d...