What is vibration drilling?

[vī′brā·shən ′dril·iŋ] (mechanical engineering) Drilling in which a frequency of vibration in the range of 100 to 20,000 hertz is used to fracture rock.

What are the three types of drillstring vibration?

Drillstring vibrations can be divided into three types, or modes: axial, torsional, and lateral (Fig.

What causes stick slip drilling?

One such phenomenon is stick slip – a form of torsional vibration that occurs when the bit, bottom hole assembly (BHA) and/or drill string experience different rotational speeds than expected. This causes the drill string to unwind and the bit RPM to speed up at a dangerous rate.

What is meant by torsional vibration?

Torsional vibration is angular vibration of an object—commonly a shaft along its axis of rotation. Also, the components transmitting the torque can generate non-smooth or alternating torques (e.g., elastic drive belts, worn gears, misaligned shafts).

What is stick slip vibration?

Stick—slip vibrations are self-sustained oscillations induced by dry friction. They occur in engineering systems as well as in our everyday life, e.g. the sound of bowed instruments results from stick—slip vibrations of the strings. Results from numerical simulations and experimental observations could be obtained.

How do you overcome stick slips?

How to Avoid Stick-Slip in Your Seals

1. Material hardness, elasticity, friction, and chemical properties: ensure compatibility between surfaces.
2. Surface roughness: ensure shafts or cylinders are neither too smooth nor too rough.
3. Fluid lubricity: change fluid if necessary, or use oil treatments or friction reducers.

What is lateral vibration?

A vibration in a helicopter in which the rotor moves back and forth in a lateral plane, or side-to-side direction. Lateral vibration is often caused by an unbalanced main rotor.

What does torsion mean in medical terms?

1 : the twisting of a bodily organ or part on its own axis intestinal torsion. 2 : the twisting or wrenching of a body by the exertion of forces tending to turn one end or part about a longitudinal axis while the other is held fast or turned in the opposite direction also : the state of being twisted.

How do you stop a stick-slip?

What is sticking condition?

In hot forging of steel and other alloys the coefficient of friction is high and also little or no lubricant is used. In such a condition, a layer of metal contacting the die-surface may stick onto the die and flow may take place just under the surface layer. This condition of friction is called sticking friction.

How do you stop this stick-slip motion?

What is slip friction?

Definition of slip friction : a friction clutch permitting slip when excessive power is transmitted.

What are the different types of drill-string vibrations?

In brief, drill-string vibrations can be analyzed from three modes: axial, torsional and lateral. The coupling between them is an essential system nonlinearity being associated with several causes. Axial-torsional coupling can be provided by drill-bit cutting process that establishes a combination of rotation and compression on the rock.

Is drill-string vibration axial-torsional coupling?

This paper deals with a coupled drill-string vibration considering a four-degree of freedom nonsmooth model that presents axial-torsional-lateral coupling. Bit-rock and wellbore interactions, eccentricity and hydrodynamic forces due to fluid resistance to lateral bending are the main system coupling aspects.

Are drill-string vibrations in deep-water oil exploration nonlinear?

Deep-water oil exploration has several technological challenges and drill-string vibrations appear as a critical situation. In brief, drill-string vibrations can be analyzed from three modes: axial, torsional and lateral. The coupling between them is an essential system nonlinearity being associated with several causes.

How to analyze drill-string vibration dynamics?

Drill-string dynamics may be analyzed by considering different vibration modes: axial, torsional and lateral. The coupled analysis of these modes gives a proper comprehension of the system dynamics, elucidating several critical vibration responses. In general, lumped models present a proper description of the system dynamics.