Abstract: Statistical Analysis of Geochemical Spatial Point Patterns

James M. Fausnaugh

The statistical theory of spatial point pattern analysis is the study of patterns of points in a plane. This process successfully estimates the frequency of gas wells located within an oil field and determines the frequency of producing wells where a large number of wildcat wells are drilled. When used with geochemical data, the same method gives a frequency estimate of the spatial variation of geochemical anomalies. In large, sparsely sampled reconnaissance surveys, spatial point analysis identifies "clusters" of anomalies which may require more detailed sampling. In smaller surveys with a high density of data, spatial point analysis focuses on the more significant anomalies.

Interpretation of the spatial patty is facilitated by graphical presentation of distance "r" and the function L(r) which is a randomness estimation relative to the Poisson model. Clustering of points occurs if there are more points in the vicinity of an arbitrary point then predicted by the Poisson model. When the estimated number of points is more than expected in the vicinity of an arbitrary point than anticlustering occurs.

AAPG Search and Discovery Article #90959©1995 AAPG Rocky Mountain Section Meeting, Reno, Nevada