Abstract:

Dynamic reservoiring process of hydrocarbon in Niu-35 and Ying-11 sandbodies in Dongying depression have been studied by using homogenization temperature of fluid inclusion, in combination with burial history and palaeogeothermal data. This paper systematically analyzes the evolution of source rocks, porosity and permeability evolution of sandsbodies, the time of hydrocarbons charging into the sandbodies, and the time of overpressure being formed on the basis of dynamic modeling of burial, thermal and hydrocarbon-charging histories. Based on comprehensive analysis, it is believed that a palaeotemperature of 90℃ and a palaeopressure of 17 MPa are favorable for the formation of lithologic reservoirs. Charging of large amount of hydrocarbons during-after reservoiring can lead to overpressured formations. sandbodies located in various reservoiring systems would have different fill factors and pressure coefficients. When sources of hydrocarbons are abundant, lenticular lithologic reservoirs with high fill factor and large pressure coefficient can be formed in deep and closed reservoiring systems, while lithologic reservoirs with moderate fill factor and relatively high pressure coefficient can be formed in half-open reservoiring systems.

Key words: fluid inclusion, Dongying depression, lithologic reservoir, dynamic reservoiring, reservoiring system