Pafitis
Demosthenis Pafitis, Cambridge GB
Patent application number | Description | Published |
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20110220417 | DRILL BITS AND METHODS OF DRILLING CURVED BOREHOLES - The invention provides drill bits and methods of drilling curved boreholes. One aspect of the invention provides a drill bit including a bit body and one or more blades positioned within the bit body, the one or more blades individually actuatable to a plurality of cut depths. Another aspect of the invention provides a method for drilling a curved borehole. The method includes: providing a drill string including a drill bit including a bit body and one or more blades positioned within the bit body, the one or more blades individually actuatable to a plurality of cut depths; rotating the drill string; and selectively actuating the one or more blades to a plurality of cut depths; thereby drilling a curved borehole. | 09-15-2011 |
Demosthenis Georgeou Pafitis, Cambridge GB
Patent application number | Description | Published |
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20110011644 | METHODS AND APPARATUS FOR ATTENUATING DRILLSTRING VIBRATIONS - 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. | 01-20-2011 |
Demosthenis Georgiou Pafitis, Cambridge GB
Patent application number | Description | Published |
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20120292115 | Drill Bits and Methods of Drilling Curved Boreholes - The invention provides drill bits and methods of drilling curved boreholes. One aspect of the invention provides a drill bit including a bit body and one or more blades positioned within the bit body, the one or more blades individually actuatable to a plurality of cut depths. Another aspect of the invention provides a method for drilling a curved borehole. The method includes: providing a drill string including a drill bit including a bit body and one or more blades positioned within the bit body, the one or more blades individually actuatable to a plurality of cut depths; rotating the drill string; and selectively actuating the one or more blades to a plurality of cut depths; thereby drilling a curved borehole. | 11-22-2012 |