东营凹陷沙四段烃源岩留-排烃量的实验研究

Experimental study on hydrocarbon retention-expulsion of Es4 formation source rock in the Dongying Depression

东营凹陷沙四段是渤海湾盆地优质烃源岩层,具有丰富的油气资源。选取沙四段烃源岩,运用IH-Tmax图,进行了演化趋势分析。采用溶胀实验对烃源岩的留烃能力进行模拟研究,结合该地区的生烃特征和生烃过程,对沙四段留-排烃史进行了恢复。部分样品是由同一生烃母质演化而来的,而且随着成熟度不断增加,可以视为一自然演化剖面。留烃量模拟显示,随着成熟度的增加,溶胀比下降,留烃量随之降低,其中未成熟样品留烃能力最强。液态烃中各组分的留烃量也不同,饱和烃留烃量最低,最容易从烃源岩中排出,而NSOs留烃量最大。将留烃史与盆地生烃史结合,得到东营凹陷沙四段的整个留-排烃过程。建立了自然演化系列样品留烃量的实验与评价方法。

A large amount of oil has been generated from the excellent source rock of the Es4 formation in the Dongying Depression, Bohai Bay Basin. The evolving trend of the source rock is analyzed by using the IH vs. Tmax plot. Combining the simulation of the hydrocarbon retention potential, which is acquired by the solvent swelling experiment, with the hydrocarbon generation characteristics and process of this area, the retention and expulsion history of the Es4 formation are restored. With increasing maturity, some samples evolved from the same hydrocarbon-generated parent material can be regarded as a natural profile. The results of the retention simulation show that the volumetric swelling ratio and the amount of retention are decreasing with the increasing maturity, and that the immaturity sample has the largest retention hydrocarbon potential. The group-type fractions of the liquid hydrocarbon which retained in the source are not the same, saturates have the minimum hydrocarbon retention and it means that saturates are most easily expulsed from the source rocks. However, the NSOs （resins and asphaltenes） have the largest retention hydrocarbon potential. Combining the hydrocarbon retention history with the generation history of the basin, the whole retention-expulsion process of the Dongying Depression can be obtained. Therefore, the hydrocarbon retention experiment and evaluation method for the natural profile samples are established.