Data laundering by target rotation in chemistry-based oil exploration

Abstract

The target rotation technique can be used for removal of undesired information provided there are variables uniquely connected to such information. Oil seepage in sea-bottom sediments can be used for oil exploration. The seeped oil constituents may be present in sub-ppm concentrations and the variation in mineral composition of the sediments and contributions from bioactivity may completely dominate over the chemical fingerprint of the seepage. Target rotation to the clay content of the sediment removes the mineral composition signature, while rotations to unsaturated gases absent in seeped oil remove signatures of non-thermogenic hydrocarbons. The assignment of samples to a class of samples over a known off-shore Norway oil field was based on the residual matrix after target rotations that represented only 17% of the total variance of the standardized raw data. The assignment method is very selective and clearly points out another known oil field and suggests one potential oil field in an unexplored area. © 1996 by John Wiley & Sons, Ltd.