东营三角洲的古流向研究

PALEOCURRENT PROPERTIES OF DONGY ING DELTA IN BOHAI BAY BASIN

沉积组构分析表明，沙三中期研究区块以正常的三角洲前缘沉积为主。利用旋转钻岩心样，进行磁化率各向异性测试，通过磁极性定向最终恢复出古流向，直观地显示了东营盆地Ｘ、Ｙ、Ｚ区块的沙三中亚段沉积直接受控于东营三角洲，即流向主体与三角洲自东南而西北的进积方向相一致。综合分析研究区的物源和沉积特征，认为东营三角洲的范围应扩大，这预示着东营凹陷沙三中岩性油藏勘探有着更为广阔的领域和良好的前景；沉积物磁各向异性的研究方法本身也为古湖泊三角洲流向分析提供了新手段，为油气勘探的深化提供了新的科学依据。

Sedimentary fabric analysis shows that middle member Ⅲ of Shahejie Formation (S m3) is mainly composed of normal deltafront sediments in this study areas. Magnetic anisotropy measurements were carried out on samples from rotary drilli ng cores, and the results were used to calculate the direction of paleocurrent oriented by magnetic polarity. The distribution of paleocu rrent, coinciding with the prograding direction of the Dongying Delta from t he southeast to northwest, distinctly manifests that in the study areas, X, Y an d Z blocks in Dongying depression are directly controlled by Dongying Delta duri ng the sedimentary epoch of Sm3. The comprehensive analysis on the sourc e and the sedimentary characteristics proves that area of Dongying Delta should be expanded. Thus, there will be widening area in the Dongying Delta inferred to be further prospect of lithological oil pool exploration. The method shown in t his paper could be a new way to analyze the paleocurrent in paleolimnological delta and will provide new scientific data to serve the petroleum exploration.