Abstract: Methods and apparatus for harvesting energy while moving a tool through a well are shown and described. The harvested energy can be used by the tool to perform work once it reaches an intended location in the well, or along the way. A considerable amount of potential energy is typically lost by oilfield tools as they move down through a borehole. Methods and apparatus described herein recover and/or store some of the energy during the downward movement of the tool.

Abstract: According to the invention, a system for drilling a cavity in a medium is disclosed. The system may include a bottom hole assembly. The bottom hole assembly may include a first longitudinal segment and at least one drill bit. The first longitudinal segment may include a first length of chassis having a first cross section. The first cross section may be configured such that the first longitudinal segment may have a greater stiffness in a first lateral direction than in a lateral direction different than the first lateral direction.

Abstract: Apparatus and methods are described for highly attenuating vibrations of a drillstring assembly while drilling. In one embodiment, vibrations are attenuated by introducing one or more vibration attenuation modules at appropriate assembly locations. For example, vibration attenuation modules may be inserted at locations where vibration energy is expected to be maximal. In one embodiment the vibration attenuation modules include cavities loosely packed with particles of solid material such as sand or metallic powder. In one embodiment, the cavity walls are rough and/or include geometric features that enhance vibration energy transfer to the loosely packed particles in the cavity(ies). The vibration energy is dissipated via friction and inelastic particle-particle and particle-wall collisions that occur as a result of drillstring motion.

Abstract: Apparatus and methods are described for highly attenuating vibrations of a drillstring assembly while drilling. In one embodiment, vibrations are attenuated by introducing one or more vibration attenuation modules at appropriate assembly locations. For example, vibration attenuation modules may be inserted at locations where vibration energy is expected to be maximal. In one embodiment the vibration attenuation modules include cavities loosely packed with particles of solid material such as sand or metallic powder. In one embodiment, the cavity walls are rough and/or include geometric features that enhance vibration energy transfer to the loosely packed particles in the cavity(ies). The vibration energy is dissipated via friction and inelastic particle-particle and particle-wall collisions that occur as a result of drillstring motion.

Abstract: According to the invention, a system for drilling a cavity in a medium is disclosed. The system may include a bottom hole assembly. The bottom hole assembly may include a first longitudinal segment and at least one drill bit. The first longitudinal segment may include a first length of chassis having a first cross section. The first cross section may be configured such that the first longitudinal segment may have a greater stiffness in a first lateral direction than in a lateral direction different than the first lateral direction.

Abstract: Methods and apparatus for harvesting energy while moving a tool through a well are shown and described. The harvested energy can be used by the tool to perform work once it reaches an intended location in the well, or along the way. A considerable amount of potential energy is typically lost by oilfield tools as they move down through a borehole. Methods and apparatus described herein recover and/or store some of the energy during the downward movement of the tool.

Abstract: Apparatus and methods are described for highly attenuating vibrations of a drillstring assembly while drilling. In one embodiment, vibrations are attenuated by introducing one or more vibration attenuation modules at appropriate assembly locations. For example, vibration attenuation modules may be inserted at locations where vibration energy is expected to be maximal. In one embodiment the vibration attenuation modules include cavities loosely packed with particles of solid material such as sand or metallic powder. In one embodiment, the cavity walls are rough and/or include geometric features that enhance vibration energy transfer to the loosely packed particles in the cavity(ies). The vibration energy is dissipated via friction and inelastic particle-particle and particle-wall collisions that occur as a result of drillstring motion.