Journal of Petroleum Geology, vol. 19(3), July 1996, pp. 339-350
©Copyright 1996. Scientific Press, U.K. All rights reserved.
FRACTALS AND THEIR APPLICABILITY IN GEOLOGICAL
WIRELINE LOG ANALYSIS
J. Pang* and C. P. North**
A fractal analysis method (rescaled-range analysis) was applied to
wireline logs through the fluvio-deltaic Brent Group (Middle Jurassic) in the Dunlin
field, northern North Sea, to test the applicability of fractal analysis in geological
interpretation of subsurface data. This analysis reveals that the fractal dimensions of
gamma-ray logs range from 1.0025 to 1.1033. A higher-fractal dimension may indicate more
heterogeneous lithologies or reservoirs. Analysis of the procedures adopted suggests,
however, that fractal concepts in wireline log analysis should be treated with caution.
Changes in the calculation procedure can cause larger variations in the estimate of the
fractal dimension for a single well than is seen between wells. The validity and
suitability of fractals in geological wireline log analysis need to be considered
carefully.