Abstract: China is rich in continental shale oil resources,but no substantial breakthrough has been made in their deve-lopment over recent years.In view of the issue,various data including thin section observation,rock pyrolysis,low-temperature nitrogen adsorption (LTNA),shale oil adsorption experiment,high pressure mercury injection (HPMI) experiment,and nuclear magnetic resonance (NMR) are integrated to investigate the major factors controlling shale oil accumulation and mobility in Biyang Depression.The results show that the TOC of shale interval enriched with oil is relatively higher,and its inorganic macropores are well developed.The shale reservoir enriched with oil is usually characterized by higher content of saturated hydrocarbon and lower content of asphaltene,so the shale oil has higher mobility.Clay minerals are the main contributor to the specific surface area of shale and the main carrier for shale oil adsorption.Thus,the lower the clay mineral content,the better the mobility of shale oil.The optimal depth for shale oil enrichment is 2 800 m in Biyang Depression.When the burial depth exceeds 3 000 m,the shale oil has a higher API degree and lower viscosity,thus fair mobility.The depth of Wells HF1 and Anshen1 is in the range from 2 400 m to 2 500 m,being shallower compared with the optimal depth for shale oil production.In addition,the adsorption capacity of small molecular hydrocarbons is relatively weaker under high temperature,so the deep intervals (over 3 000 m in depth) are the play fairway for petroleum exploration in the area.The pressure coefficient of Biyang formations is relatively small,and the higher interval transit time mainly indicates higher TOC.

Key words: mobility, reservoir capacity, hydrocarbon enrichment, shale oil, Biyang Depression, Nanxiang Basin