Fracture sampling on a cylinder: From scanlines to boreholes and tunnels

SummaryIn this paper we develop correction factors for orientation bias when sampling rock fractures with a borehole. For a borehole with zero radius we obtain Terzaghi's result for scanline sampling: otherwise the appropriate correction factor may differ significantly from that obtained for the scanline model, depending on the relative size of the borehole and the rock fracture. Two separate cases are discussed: the sampling of fractures with a borehole and sampling with the surface of a borehole. Analytical expressions for the correction factors are graphed and tabulated.

[1]  E. T. Brown,et al.  Maximum likelihood estimation of joint size from trace length measurements , 1992 .

[2]  William Dershowitz,et al.  Discrete Fracture Approaches for Oil and Gas Applications , 1994 .

[3]  R. D. Terzaghi.  Sources of Error in Joint Surveys , 1965 .

[4]  M. Oda,et al.  Permeability tensor for discontinuous rock masses , 1985 .

[5]  S. Priest,et al.  ESTIMATION OF DISCONTINUITY SPACING AND TRACE LENGTH USING SCANLINE SURVEYS , 1981 .

[6]  W. Dershowitz,et al.  Interpretation of fracture spacing and intensity , 1992 .

[7]  Nicholas Anthony Lanney,et al.  Statistical description of rock properties and sampling. , 1978 .

[8]  P. J. Pahl,et al.  Estimating the mean length of discontinuity traces , 1981 .

[9]  S. Priest.  Discontinuity Analysis for Rock Engineering , 1992 .

[10]  G. W. Wathugala,et al.  A general procedure to correct sampling bias on joint orientation using a vector approach , 1990 .

[11]  Paul R. La Pointe,et al.  Pattern Analysis and Simulation of Joints for Rock Engineering , 1993 .

[12]  Masanobu Oda,et al.  FABRIC TENSOR FOR DISCONTINUOUS GEOLOGICAL MATERIALS , 1982 .

[13]  John A. Hudson,et al.  Characterization and Interpretation of Rock Mass Joint Patterns , 1985 .

[14]  H.S.W. Pinnaduwa,et al.  Three dimensional stochastic joint geometry modeling including a verification: A case study , 1990 .

[15]  M. Mauldon.  Intersection probabilities of impersistent joints , 1994 .

[16]  Pinnaduwa Kulatilake,et al.  Estimation of mean trace length of discontinuities , 1984 .

[17]  P. M. Warburton,et al.  A STEREOLOGICAL INTERPRETATION OF JOINT TRACE DATA , 1980 .

[18]  J. L. Yow,et al.  Blind zones in the acquisition of discontinuity orientation data , 1987 .