Quantitative characterization of various oil contents and spatial distribution in lacustrine shales: Insight from petroleum compositional characteristics derived from programed pyrolysis

The strong heterogeneity of lacustrine shale oil occurrences and the lack of proper parameters representing the shale oil content are impediments to assessing shale oil reserves. The shale oil content was characterized in the study using petroleum compositional characteristics determined by loss light hydrocarbon restoration and chemical kinetics decomposition and reconstruction of hydrocarbon groups; the shale oil spatial occurrence of the Second Mbr of the Funing Fm in Haian Sag, Subei Basin was determined using logging prediction and measured data; and finally, the controlling factors of shale oil content were discussed. Organic matter abundance, thermal maturity, and lithofacies have the primary impact on shale oil content. Shale oil enrichment intervals are distributed in an adjacent part of the maximum flood surface in the third-order sequence and some ascending semi-cycles in the fourth-order sequences in the deep sag area. This work has implications for exploration target optimization and resource potential evaluation of shale oil.