The characterization of surface carbon on organic bearing shale by Auger lineshape analysis

Abstract

An investigation of the Auger lineshapes of individual organic compounds indicated the presence of positive-going peaks in differential Auger Spectra which correspond to the presence of φ-bonds, aliphatic chains and methyl or methylene groups. Also it was discovered that the intensity of the negative-going differential peak or EN( E) area was proportional to the reciprocal of two raised to the number of methyl of methylene groups present in an organic compound. This last relationship can readily yield a measure of cross-linking or methyl substitution on the surface of an organic compound or polymer. The following equation summarizes the relationship: I/ I 0 = 1/(2 S ), where I is a peak intensity, I 0 is the peak intensity of a compound with no methyl or methylene substitution, and S is the number of methyl or methylene groups substituted. Samples of eastern and western shales were examined and the Auger lineshapes analyzed. The Auger lineshapes of the organic material on the surface of the shale indicated that western shales and especially Colorado shale had a greater aliphatic character than eastern shales. The eastern shales had more φ-bond substitution than western shales.