Abstract
We describe a method to estimate fracture length for circular fractures from borehole image logs. The relative frequency of fractures, which have complete circumference trace on image logs is related to fracture length. A simple functional relationship can be derived for the relative frequency of complete fracture traces in terms of average fracture inclination to borehole, borehole diameter and fracture length. This formulation however, tends to underestimate fracture length because a constant length is assumed. A more accurate length estimate can be obtained by assuming that fracture length is linearly correlated to fracture aperture or spacing. Cumulative frequency distribution of fracture aperture and spacing can be obtained from borehole image logs. The problem then transforms itself to finding the scaling factor between fracture length and aperture (or spacing) from the relative frequency of fractures with complete traces. The product of the scaling factor and average fracture spacing (or aperture) gives the average fracture length.
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References
Bai, T., and Pollard, D., 2000, Fracture spacing in layered rocks: A new explanation based on the stress transition: J. Struct. Geol., v.22, p. 43-57.
Belfield, W. C., 1998, Incorporating spatial distribution in stochastic modelling of fractures: Multifractals and Levy-stable statistics: J. Struct. Geol., v.20, p. 473-486.
Cartwright, J. A., Trudgill, B., and Mansfield, C. S., 1995, Fault growth by segment linkage: An explanation for scatter in maximum displacement and trace length data from the Canyonlands grabens of SE Utah: J. Struct. Geol., v.17, p. 1319-1326.
Clark, R. M., and Cox., S. J. D. 1996. A modern regression approach to determining fault displacement length scaling relationship: J. Struct. Geol., v.18, p. 147-152.
Cowie, P. A., and Scholz, C., 1992, Displacement–Length scaling relationship for faults. Data synthesis and discussions: J. Struct. Geol., v.14, p. 1149-1156.
Jamison, W. R., 1997, Quantitative evaluation of fractures on Monkshood anticline, a detachment fold in the foothills of western Canada: Am. Assoc. Petroleum Geologists Bull., v.81, p. 1110-1132.
Johnston, J. D., and McCaffrey, K. J. W.,1996, Fractal geometries of vein systems and the variation of scaling relationships with mechanism: J. Struct. Geol., v.18, p. 349-358.
LaPointe, P. R., and Hudson, J. A., 1985, Characterization and interpretation of rock mass joint patterns: Geol. Soc. Am. Special Pap. 199, 37 p.
Luthi, S. M., and Souhaite, P., 1990, Fracture apertures from electrical borehole scans: Geophysics: v.55, p. 821-833.
Olson, J. E., 1993, Joint pattern development: Effects of subcritical crack growth and mechanical crack interaction: J. Geophys. Rese., v.98(B7), p. 12, 251-212, 265.
Ozkaya, S. I., and Mattner, J., 2003, Fracture connectivity from fracture intersections in borehole image logs: Comput, Geosci., v.29, p. 143-153.
Peacock, D. C. P., 1991, Displacements and segment linkage in strike slip fault zones: J. Struct. Geol., v.13, p. 1025-1035.
Rohrbaugh, M. B., Jr., Dunne, W. M., and Mauldon, M., 2002, Estimating fracture trace intensity and mean length using circular scan lines and windows: Am. Assoc. Petroleum Geologists Bull., v.86, p. 2089-2104.
Vermilye, J. M., and Scholz, C. H., 1995, Relation between vein length and aperture. J. Struct. Geology., v.17, p. 423-434.
Walsh, J. J., and Watterson, J., 1988, Analysis of the relationship between displacement and dimensions of faults: J. Struct. Geol., v.10, p. 239-247.
Wu, H., and Pollard, D. D., 1995, An experimental study of the relationship between joint spacing and layer thickness: J. Struct. Geol., v.17, p. 887-905.
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Özkaya, S.I. Fracture Length Estimation from Borehole Image Logs. Mathematical Geology 35, 737–753 (2003). https://doi.org/10.1023/B:MATG.0000002987.69549.ba
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DOI: https://doi.org/10.1023/B:MATG.0000002987.69549.ba