Shape memory alloy vibration isolation device

Abstract

Methods and apparatus for mitigating the effects of vibration of various tools, such as those used downhole, by utilizing a vibration isolation device that incorporates Shape Memory Alloys (SMAs). For instance, in some embodiments, a vibration isolation device may be designed and deployed in a manner such that, when a vibration isolation device is operated in an expected manner, the force on the SMAs from static loading is sufficient to induce partial phase transformation between the austenite and martensite phases. This partial phase transformation may result in a reduced stiffness of the vibration isolation device in comparison to a tool in either a full austenite phase or full martensite phase.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application No. 60 / 844,033, filed Sep. 12, 2006.BACKGROUND[0002]1. Field of the Invention[0003]Embodiments of the present invention generally relate to isolating and reducing vibrations generated by the operation of downhole tools, such as those used in the exploration, production, and / or processing of hydrocarbons.[0004]2. Description of the Related Art[0005]Vibrations are often encountered at various times when exploring for, producing, and processing hydrocarbons. Vibrations may affect not only the performance of tools, but may also cause these tools to fail prematurely if the vibrations are sustained or extreme. One application where vibrations present particular challenges is when drilling subsurface wells with a drill bit at the end of a rotating drill string.[0006]When drilling a wellbore, two main sources of vibrations are typically present. First, vibrations may be generated...

AI Technical Summary

Benefits of technology

[0010]Embodiments of the invention generally provide techniques for reducing the adverse effects of vibration.

Problems solved by technology

Vibrations may affect not only the performance of tools, but may also cause these tools to fail prematurely if the vibrations are sustained or extreme.

One application where vibrations present particular challenges is when drilling subsurface wells with a drill bit at the end of a rotating drill string.

First, vibrations may be generated at the face of the drill bit in contact with the rock formation being drilled.

The amplitude of these vibrations may be particularly high when drilling through hard rock formations.

Second, vibrations may be generated in the drill string due to the rotation of the drill string.

Vibrations may lead to different undesirable effects, such as reduced rate of penetration of the drill bit, damage to sensitive downhole tools (e.g., electronic components), as well as reduced life of and / or damage to the drill bit, and fatigue of the drill string.

Unfortunately, this approach is somewhat limited because the parameters or combination of parameters that lead to excessive vibration for a given bottom hole assembly (BHA) may not be known.

In addition, it may be necessary to change the rotary speed and / or the weight-on-bit in an effort to maintain a desired rate of penetration during drilling operations, which may result in inadvertent entry into a combination of parameters causing large vibrations.

Some types of shock subs may perform reasonably well in reducing the axial vibrations, but unfortunately, their effect on lateral vibrations is not consistent and tends to vary for different shock sub designs.

In fact, some shock subs may actually increase lateral vibrations.

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