东营凹陷E-N岩浆活动对E_(s3-4)泥质岩生烃范围的影响

The effect of the Paleogene-Neogene magmation on hydrocarbon-generating region of the upper E_(s3-4)—middle E_(s3) dark argillaceous rocks in Dongying Depression

目的探讨东营凹陷古近纪—新近纪岩浆活动对沙四上段—沙三中段暗色泥质岩生烃范围的影响。方法以东营凹陷160余口钻井、录井的岩浆岩资料为基础,编制古近系—新近系岩浆岩的分布图,对岩浆岩分布区的现今地温和古地温特征以及岩浆岩分布区的沙四上段—沙三中段暗色泥质岩的厚度、埋深和生烃特征进行研究。结果东营凹陷古近系和新近系岩浆岩主要分布于凹陷西部和南部,岩浆岩分布区沙四上段—沙三中暗色泥质岩埋深一般较浅(800～2 000 m);其现今地温梯度普遍偏高,一般在3.6～5.0℃/100 m;古近纪、新近纪岩浆活动期,该区具有更高的地温特征,其泥质岩有机质生烃门限深度可小于1 170 m。结论东营凹陷古近纪—新近纪,岩浆活动控制的沙四上段—沙三中暗色泥质岩有效生烃范围主要分布于东营凹陷西部和南部暗色泥质岩埋深较浅的区域。与由埋深增温作用控制的沙四上段—沙三中暗色泥质岩生烃范围在平面上形成了互补,致使沙四—沙三段暗色泥质岩的有效生烃范围几乎覆盖了整个凹陷。在油气勘探过程中,应充分考虑东营凹陷古近纪—新近纪岩浆活动控制的沙四上段—沙三中暗色泥岩有效生烃范围对油气藏形成与分布的影响,并加强在埋深较浅的受岩浆活动影响的暗色泥岩分布区页岩油气藏的勘探。

Aim To probe effect of Paleogene--Neogene ceous rocks in the E^3.4 in Dongying Depression. Methods magmation on hydrocarbon-generating region of argilla Using the data of magmatic rocks derived from the drill- ing wells and logs of approximate 160 wells to plot the map for distribution of the Paleogene--Neogene magmatic rocks in Dongying Depression, to study the characteristics of the present geotemperature and paleogeotemperature, and the characteristics of the thickness and burial depth and hydrocarbon generation of the upper E^4--middle E^3 dark argillaceous rock in the region of magmatic rocks distribution. Results The Paleogene--Neogene magmatic rocks are mainly distributed in the west and south of Dongying Depression. In this area, the burial depth of the up- per E^a--middle E^3 dark argillaceous rocks are relatively shallow, generally ranging from 800 to 2 000m, the pres- ent geothermal gradients are relatively high, generally ranging from 3.6 to 4.0℃/100m, the paleogeotemperature in the period of the Paleogene--Neogene magmatic activity is much higher than the present geotemperature, and the hydrocarbon-generating threshold depth is less than 1 170 m. Conclusion The effective hydrocarbon-generating re- gion of the upper Ea--middle E,3 dark argillaceous rocks relating to the Paleogene-Neogene magmation is mainly distributed in the area of shallow burial depth of dark argillaceous rocks, the western and southern Dongying depres- sion, which is complementary to the effective hydrocarbon-generating region of the upper Ea--middle E^3 dark ar- gillaceous rocks relating to burial depth in a plane, resulting in the effective hydrocarbon-generating region of the upper E4--middle Es3 dark argillaceous rocks almost covering the entire Dongying depression. During the explora- tion of oil and gas in the Dongying depression, it should be fully taken account of the effects of the effective hydro- carbon-generating region of the upper E4--middle E^3 dark argillaceous rocks relating to the Paleogene--Neogene magrnation on the formation and distribution of oil and gas reservoir, and the exploration of shale oil and gas reser- voir in the area of shallow burial depth of dark argillaceous rocks affected by the Paleogene--Neogene magmation should be strengthened.