Effect of Long-term Weathering in Mixtures with Different Mixing Ratios of Oils from Two Oil Fields

Oil collected from Tarim oilfield was poured with different proportions into oil collected from Shengli oilfield. The mixed oil samples were placed in an artificial climate chamber to simulate a 160-days weathering process and reveal long-term weathering effects on conventional biomarker diagnostic indicators of n-alkanes in these mixed oil samples. The results show that only CPI2 in all common characteristic ratios of the experimental oils are suitable as the characteristic ratios for oil identification in long-term weathering processes (160d). The fact that a common diagnostic ratio of an oil sample after a serious weathering process changed more shapely than its original oil, maybe manifest that the original oil sample is a one with mixed source.