Using the Hypergeometric Model to analyze the buckling of drillstrings in curved boreholes
- Colorado School of Mines, Golden, CO (United States). Petroleum Engineering Dept.
Current methodologies for analytically determining the onset of buckling of drillstrings within curved boreholes are limited. In this paper, the Hypergeometric Model is shown to be an effective model to determine drillstring buckling within curved boreholes. With the Hypergeometric Model, the analysis of drillstring buckling results in curves expressing the local buckling force versus the angle of inclination. The local buckling force alone, however, does not contain all the information required for a practical analysis. From the local buckling force curve, the positional buckling force is derived. The positional buckling force considers the distributed weight of the drillstring and the friction between the drillstring and the borehole wall. From this curve, the point of minimum resistance to buckling of the drillstring is determined. Using the local and positional buckling force curves, experimental results and simulations are presented. When multiple configurations exist (for example tapered drillstrings, tapered boreholes, multi-curved boreholes, or any combination of these), the analysis procedure uses superposition of two or more single configuration curves and a graphical algorithm. The Hypergeometric Model permits the optimization of the position of the crossing points (cross-over positioning, casing-shoe positioning, and change of curvature) to achieve extended reach with less risk and cost. The procedure for this model and examples are presented in this paper.
- OSTI ID:
- 357734
- Report Number(s):
- CONF-980213-; TRN: IM9932%%79
- Resource Relation:
- Conference: 1998 energy sources technology conference, Houston, TX (United States), Feb 1998; Other Information: PBD: 1998; Related Information: Is Part Of Proceedings of the 1998 ASME energy sources technology conference (ETCE`98); PB: [1170] p.
- Country of Publication:
- United States
- Language:
- English
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