FRA--A Computer Program That Uses a Fractal Methodology to Calculate the Volume and Number of Undiscovered Hydrocarbon Accumulations
Christopher C. Barton and Grigori L. Troussov
A new method based on fractal geometry has been developed and computerized for assessing the size, number, and total volume of undiscovered, conventionally recoverable hydrocarbon accumulations based on fitting a truncated fractal (power-law) distribution to a log-log plot of the cumulative size-frequency distribution of discovered accumulations in a play or other geologically or geographically defined region.
The computer program, FRA, is written in Borland C++ version 4.5 and performs calculations of the size and number of hydrocarbon accumulation remaining undiscovered. For a play or other geologically or geographically defined region, the user designates the minimum accumulation size to be considered and the accumulation size (which we term the perceptibility limit above which, in the user's judgment, all or most of the accumulations have been discovered. The program then fits a truncated power-law to the accumulations above the perceptibility limit and extrapolates the power-law down to the smallest accumulation volume selected by the user. Output from FRA is (1) a series of log-log plots of the discovered accumulations fit by fractal (power) distributions, (2) a histogram of the numbe of undiscovered accumulations binned into size (volume) classes, and (3) a listing of parameter calculated by the program. Parameters include the volume and percentage undiscovered hydrocarbons between the perceptibility limit selected and smallest accumulation size (volume) selected. FRA has been tested on several hundred plays and regions from the USGS 1995 National Assessment of the United States oil and gas resources, from the Gulf of Mexico, and from other petroleum producing regions of the world.
AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California