Research Papers: Natural Gas Technology

Analytical Model to Estimate the Drag Forces for Microhole Coiled Tubing Drilling

[+] Author and Article Information
Yuan Zhang

e-mail: yzhang6@uh.edu

Ye Hao

e-mail: yhao3@uh.edu
Petroleum Engineering Program,
University of Houston,
Houston, TX 77204

Robello Samuel

Halliburton Technology Fellow,
Houston, TX 77041
e-mail: robello.samuel@halliburton.com

1Corresponding author.

Contributed by the Petroleum Division of ASME for publication in the Journal of Energy Resources Technology. Manuscript received January 2, 2013; final manuscript received March 13, 2013; published online June 3, 2013. Assoc. Editor: Hameed Metghalchi.

J. Energy Resour. Technol 135(3), 033101 (Jun 03, 2013) (7 pages) Paper No: JERT-13-1003; doi: 10.1115/1.4024044 History: Received January 02, 2013; Revised March 13, 2013

Microhole coiled tubing drilling is a new technology that provides many added advantages but at the same time poses numerous operational challenges. This manifests itself in a number of ways, all of which adversely affect the efficiency of the drilling process. These problems include increased wellbore friction, poor hole-cleaning, tubular failures, and associated problems during tripping operations. Presently conventional torque and drag models are used to calculate drag forces and surface loads during microhole coiled tubing drilling. However, these estimates might be under conservative. Therefore, an improved model and more comprehensive analysis are required. Conditions expected during microhole coiled tubing drilling are completely different from those encountered during conventional drilling. Further complexity is added when the wellbore is undulated. This paper describes a new analytical model for estimating drag forces by assuming that pipe in the horizontal portion follows a sine function wave due to residual bends and snubbing force. In addition, the model takes into account when the wellbore is also tortuous. Fluid viscosity (an important force in the microhole) is also included so we can calculate appropriate surface loads in addition to drag. This study concludes that besides wellbore inclination, curvature, and wellbore torsion, parameters such as wavelength and contact area also influence the results. This paper documents the comparison between the predicted mathematical simulation results with actual data from wells describing the accuracy and applicability of the model. The analysis results and comparison are presented along with three examples (Zhang et al., 2013, “Analytical Model to Estimate the Drag Forces for Microhole Coiled Tubing Drilling,” Society of Petroleum Engineers, Paper No. SPE 163480.).

Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.


U.S. Department of Energy, 2003, Microdrill Initiative Initial Market Evaluation, Spears & Associates, Inc., Tulsa, OK.
Perry, K., 2009, “Microhole Coiled Tubing Drilling: A Low Cost Reservoir Access Technology,” ASME J. Energ. Resour. Technol., 131(1), p. 013104. [CrossRef]
Albright, J., Dreesen, D., Anderson, D., and Blacic, J., 2005, Road Map for a 5000 ft Microborehole, Los Alamos National Laboratory, Lithos Associates and Nambe Geophysical, Inc., Los Alamos, NM.
Newman, K., Kelleher, P., and Smalley, E., 2007, Friction Reduction for Microhole CT Drilling, CTES, L.P. Conroe, TX.
Samuel, R., and Liu, X., 2009, Advanced Drilling Engineering—Principles and Designs, Gulf Publishing Company, Houston, TX.
Xiao, W., Zhang, Y., and Zhong, Y., 2003, “Annulus Whirling Motion Analysis of the Rotary Drill String by the Action of Hydrodynamic Pressure and Friction Force,” ASME 2003 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference (IDETC/CIE2003), Chicago, IL, Paper No. DETC2003/VIB-48423, pp. 1003–1010.
Zifeng, L., Xuejiao, L., and Peng, W., 2012, “Prebending Coiled Tubing and Its Fatigue Life Prediction,” ASME J. Energ. Resour. Tech., 134(3), p. 034502. [CrossRef]
Tikhonov, V. S., and Safronov, A. I., 2011, “Analysis of Postbuckling Drillstring Vibrations in Rotary Drilling of Extended-Reach Wells,” ASME J. Energ. Resour. Technol., 133, p. 043102. [CrossRef]
Qui, W., Miska, S., and Volk, L., 1999, “Effect of Coiled Tubing Initial Configuration on Buckling Behavior in Deviated Wells,” ASME J. Energ. Resour. Technol, 121(3), pp. 176–182. [CrossRef]
Eustes, A. W., III, Mitchell, B. J., and Stoner, M. S., 1994, “Selection of Slim Hole Core Rods by Vibratory Analysis,” ASME J. Energ. Resour. Technol., 116(4), pp. 251–257. [CrossRef]
Saleh, S. T., and Mitchell, B. J., 1989, “Wellbore Drillstring Mechanical and Hydraulic Interaction,” SPE California Regional Meeting, Bakersfield, CA, Paper No. 18792.
Bourgoyne, A. T., Millheim, K. K., Chenevert, M. T., and Young, F. S., 1986, Applied Drilling Engineering, Society of Petroleum Engineers, Richardson, TX.


Grahic Jump Location
Fig. 1

Microhole CTD friction reduction in horizontal wells

Grahic Jump Location
Fig. 3

Scheme of analytical model for friction estimation

Grahic Jump Location
Fig. 9

Illustration of total friction estimation

Grahic Jump Location
Fig. 10

Total friction force due to pipe length variation

Grahic Jump Location
Fig. 11

Relative value when length variation

Grahic Jump Location
Fig. 12

Total friction force due to unit waveband length variation

Grahic Jump Location
Fig. 13

Relative value when waveband length varies

Grahic Jump Location
Fig. 14

Total friction force due to contact area variation

Grahic Jump Location
Fig. 15

Relative value when contact area variation

Grahic Jump Location
Fig. 2

Tubing forces model

Grahic Jump Location
Fig. 4

Scheme of pressure difference calculation

Grahic Jump Location
Fig. 7

Illustration of viscous force calculation (outside)

Grahic Jump Location
Fig. 8

Illustration of viscous force calculation (inside)

Grahic Jump Location
Fig. 5

Shape of friction estimation analytical model

Grahic Jump Location
Fig. 6

Illustration of friction in unit differential length



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In