东营凹陷岩性油气藏动态成藏过程

利用流体包裹体均一温度,结合埋藏史和古地温资料,对东营凹陷牛35砂体和营11砂体成藏的动态过程进行了研究。通过砂体埋藏史、热史和油气充注史动态模拟,系统分析了烃源岩演化,砂体孔隙度、渗透率演化,油气充注时期及超压的形成时期等。综合分析后认为,砂体在90℃的古温度和17MPa的古压力条件下,利于形成岩性油气藏。在成藏过程中或成藏后,油气的大量充注会导致地层超压的形成。处于不同成藏系统中的砂体,其充满度以及压力系数不一致。在油源充足情况下,深层封闭成藏系统中易形成高充满度、高压力系数的透镜状岩性油气藏;而在半开放成藏系统中会形成充满度中等、压力系数较高的岩性油气藏。

A study on dynamic reservoiring process of hydrocarbon in lithologic reservoirs in Dongying depression

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.