Oil-Bearing Properties Of Terrestrial Shales Of The Shahejie Formation In The Liaohe Depression And Its Main Controlling Geological Factors

China’s terrestrial shale oil resources have great potential,with technically recoverable resources of about 80-100 billion tons,and is a key area for oil and gas reserves to increase production.At present,China’s shale oil exploration and development is still in its initial stage,with only a few areas for experimental exploration.The study concluded that the shales of the Shahejie Formation in the Liaohe Depression have good comparability with the North American shale oil commercial exploitation area in terms of organic matter abundance,type,mineral composition,porosity and oil content,but are relatively low in terms of organic matter evolution,and concluded that shale oil exploration should be the main focus.Therefore,there is an urgent need to conduct targeted research on the oil-bearing properties of onshore shales,that important to enhance the effectiveness of shale oil exploration and development in China.In this paper,the geological conditions and exploration potential of onshore shale oil reservoirs are systematically studied by using organic geochemistry,rock mineralogy and rock pyrolysis in the Shahejie Formation of the Liaohe Argentine Trap.The main insights gained are as follows:(1)The Shahejie Formation mainly develops type Ⅱ cheese roots.The shales of the Shahejie Formation are mostly in the mature stage,and the value of Ro generally exceeds 0.5%;the organic matter abundance of the shales is high.(2)The mineral composition of the Shahejie Formation in the Liaohe Depression is mainly clay minerals,followed by quartz and the least pyrite.Intergranular pores,intra-granular pores,organic matter pores,matrix pores,fractures and dissolution pores are mainly developed.(3)The light hydrocarbon recovery coefficient of chloroform asphalt "A" increased with the increase of maturity,and the light hydrocarbon recovery coefficient ranged from 0.3 to 1.73.The oil content was 3.19 mg/g on average,and the oil content value measured by low temperature dry distillation method was slightly higher than that of rock pyrolysis method,and the main body of oil content ranged from 0.4% to 0.9%.(4)With the increase of TOC content and Ro,the amount of shale free oil as well as adsorbed oil increases;the content of quartz,carbonate minerals and pyrite is positively correlated with the content of free hydrocarbons,while the content of feldspar and free hydrocarbons is negatively correlated;the content of clay minerals is positively correlated with the content of adsorbed hydrocarbons,while the content of feldspar and pyrite is negatively correlated with the content of adsorbed hydrocarbons;there is a positive correlation between the amount of shale free oil and porosity;while there is no correlation between the amount of shale adsorbed oil and porosity and permeability.