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

Novel Method for the Classification of Shale Oil Reservoirs Associated with Mobility: Inspiration from Gas Adsorption and Multiple Isothermal Stage Pyrolysis

“…The S 1‑2 , an indicator of medium hydrocarbons, , shows the highest value, ranging from 0.1 to 10.61 mg/g (mean: 3.27 mg/g). Especially, the superior S 1‑2 implies that although the medium component is free oil (Figure ), it is not prone to leakage at normal temperature and pressure. ,, The heavy components (i.e., S 2‑1 ), characterized by adsorbed oil, , vary from 0.02 to 4.23 mg/g. The remaining kerogen generation potential is heterogeneously indicated by S 2‑2 values ranging from 0.01 to 2.17 mg/g for samples (Table ).…”

“…Theoretically, oil molecules stored in shale pores mainly include heavy hydrocarbons, medium hydrocarbons, and light hydrocarbons (Figure ). Due to the affinity for a pore wall, heavy components show tremendous adsorbed performance on the wall surface. − Thus, heavy hydrocarbon molecules are characterized as adsorbed phases and are likely to be trapped in pores. , The existence of adsorbed layers weakens an interaction force between a pore wall and light-medium components, resulting in light-medium oil existing in pores as free phases. ,, It is also worth noting that light and medium hydrocarbons show different physical behaviors, prompting them to have various mobility behaviors. ,, Light oil components with high mobility are prone to leakage even during coring and storage conditions. However, medium oil components often take certain conditions (e.g., experimental heating) to be significantly lost. , Especially, previous works pointed out that an increase in the pore size leaves more free space for a lighter fluid, causing an improvement in shale oil mobility. ,, Collectively, the features of oil molecules are closely related to pore size.…”

“…34,35 The existence of adsorbed layers weakens an interaction force between a pore wall and light-medium components, resulting in light-medium oil existing in pores as free phases. 6,36,37 It is also worth noting that light and medium hydrocarbons show different physical behaviors, prompting them to have various mobility behaviors. 31,38,39 Light oil components with high mobility are prone to leakage even during coring and storage conditions.…”

“…Shale oil resources, with global technically recoverable reserves of 1.4 × 10 12 t, are about three times the total conventional oil resources . Relying on the shale oil revolution, shale oil has been leading the world’s incremental oil production in recent years. ,− Accelerating the development and utilization of shale oil is the most effective way to ensure the sustainable supply of global petroleum energy. , …”

Heterogeneity of Micro- and Nanopore Structure of Lacustrine Shales with Complex Lamina Structure

“…Shale oil refers to the liquid hydrocarbon retained in the reservoir space of organic-rich shale formations, which has the characteristics of in situ or extremely short distance migration and accumulation [1][2][3]. Shale oil reservoirs are dense, with a matrix permeability typically less than 0.001 × 10 3 µm 2 and porosity ranging from 4% to 6%.…”