Abstract:

The characteristics of pyrolysis(P-FID),thermogravimetric analysis (TGA),infrared spectrums(IR),elements composition and carbon isotope ratios of kerogen in the Palaeozoic rocks of the Shaanxi-Gansu-Ningxia Basin have been investigated,and the types of kerogen in vari-ous sequences have been described in this paper.The main types of ke-rogen favourable to oil-gas formation in this basin are sapropel(O₂)and mixed humus and sapropel(C₂b,C₃t),because of their high con-tents of C degradation hydrocarbons,It is suggested that,with the grade of metamorphism getting higher,the H/C(atomic ratio) and O/C(atomic ratio)of kerogen tend to de-crease,the H/C(atomic ratio)of asphaltene and the fractionation ofδC¹³ to increase.