Drillstring stability based on variable material cutting stiffness and using a sharp three-insert polycrystalline diamond compact (PDC) coring bit
- Univ. of Southwestern Louisiana, Lafayette, LA (United States). Mechanical Engineering Dept.
Previous research in stability of drillstrings was based on the assumption of constant Material Cutting Stiffness, i.e., a bit force that is proportional to the area of cut. Moreover, earlier work used a simplified bit model that consisted of planar radial blades. In this paper, correlation between the Material Cutting Stiffness and area of cut is obtained for Sierra White Granite and Berea Sandstone from test data developed at Sandia National Laboratories in Albuquerque, NM. These correlations, together with an improved bit model in which cylindrical cutters are arrayed in an overlapping pattern over a flat surface, are used to obtain the stability diagram for a typical drillstring. These results are useful in predicting the appropriate operating conditions for stable drilling and serve as a basis for future development of more accurate models of the PDC bit.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- OSTI ID:
- 357735
- Report Number(s):
- CONF-980213--
- Country of Publication:
- United States
- Language:
- English
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