Applications of Mango’s light hydrocarbon parameters to petroleum from Tarim basin, NW China

Light hydrocarbons in oils from the Tarim basin, NW China, were analyzed by GC. The light hydrocarbon parameters proposed by Mango revealed the distributions of the oils as two main types, marine and terrigenous sources. The Mango parameter K1 not only displays a remarkable invariance (not, vert, similar1) in most of the oils, but also shows significant variations (ranging from 1.20 to 1.54) in the oils occurring in the eastern part of the Tazhong Fault Uplift (EPTFU) located in the center of the Tarim basin. This variation of the K1 value may indicate different petroleum systems in the areas which are superimposed in the EPTFU. Parameter K2 proposed by Mango shows a significant variation between the two main oil types. The marine oils are characterized by relatively low values of K2 (average 0.23) and the terrigenous oils by relatively high K2 values (average 0.35), with general invariance within the same oil set. A plot of (P3 + P2 + N2) vs. image based on the model proposed by Mango can be used not only to discriminate between the two main genetic oils from the Tarim basin, but also to classify the marine oils from the Lunnan area into two sub-types, which may indicate two sub-petroleum systems existing in the area.