ABSTRACT: Fractal geometry in the evaluation a stratigraphic records: with an example on a well log data

Putrohari, Rovicky Dwi , Kondur Petroleum, Jakarta, Indonesia

Fractal analyses methods (R/S - rescale-range analyses and Power Spectrum analyses) were applied to evaluate a stratigraphic record using wireline logs of the fluvial to marine Lower-Middle Miocene in the Central Sumatra Basin. This study was a test the applicability of a fractal analysis of well log data especially for stratigraphic evaluation. These analyses reveal that the fractal dimension of gamma-ray logs is the best log for stratigraphic well log evaluation using fractal. The study was also suggested that the fractal dimension showing that the complexity of the deltaic sequence is simpler than the marine and fluvial sequences.

Many problems in geology and geophysics can be solved using linear equations. Examples include seismic waves, the earth's gravity and magnetic field, and problems involving heat flow and elasticity. However, other problems are essentially non-linear; the classic example is fluid turbulence. In the past twenty years major advances have been made in the understanding of nonlinear problems. In the past four years many of these advances have been applied to geophysical problems. Applications range from mantle convection to distributed seismicity to the stratigraphic structure of sedimentary basins to floods.

Modern geological science uses many physical characteristics of rocks on evaluation, all of these data indirectly mimics the geological character of the rocks. Geologists are interested in describing how some properties, such as porosity, fossil content or element abundance, and changing in stratigraphic section (sedimentary process). The description of fractals, and the determination whether a particular natural object is fractal, has led to the development of large set of mathematical techniques for the description of irregular or heterogeneous natural system. Depositional systems and stratigraphic records are good candidate to be evaluated numerically using fractal methods.

AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia