渤海湾盆地东营-惠民凹陷孔店期原型盆地分析

ANALYSIS OF THE EARLY TERTIARY PROTOTYPE BASIN IN THE DONGYING-HUIMIN SAG OF THE BOHAIWAN BASIN

东营—惠民凹陷隶属渤海湾盆地,位于济阳坳陷的南部,古新统和始新统的下部的孔店组中已获工业性油气流。孔店组的含油气远景与控制形成油气藏各要素的孔店期盆地原型密切相关。该文通过分析构造演化剖面沉积相图,认为孔店期原型盆地为北断南超的伸展半地堑,盆地长轴方向整体为近东西向,主要的控制性断层是北东东向的宁南断层、无南断层西段和陈南断层西段,北西向的陈南断层东段、无南断层东段和石村断层有重要影响。北西向构造的影响在东部大于西部,孔店早期大于晚期。太平洋板块向欧亚板块俯冲以及亚洲东部大陆边缘由安第斯型向西太平洋型转化导致上地幔隆升作用的加剧和郯庐断层由左旋走滑向右旋走滑的转化是东营—惠民凹陷孔店期盆地发育地球动力学背景。

DongyingHuimin Sag is located in the south of Jiyang Depression of the Bohaiwan Basin. Commercial oil and gas has been found in the Palaeocene and Lower Eocene Kongdian formation. Hydrocarbon potential of Kongdian formation is closely related to the Early Tertiary basin prototype that controlled formation of oil and gas reservoirs. Based on analysis of tectonic evolution and sedimentary facies, prototype basin in that period was recognized as an extending half graben that was faulted in the north and onlapped in the south. The major controlling faults included the northnortheast struck Ningnan fault, the western part of Wunan fault and Chennan fault. The Shicun fault, the east part of Chennan fault and Wunan fault that struck to northwest have also played a great part. The influence of northwest direction structures was more obvious in the east and in the early period than that in the west and in the later stage. The geodynamic background of prototype basin development of DongyingHuimin sag was the sharpening uplift of upper mantle resulted from the subduction of Pacific plate to Eurasian plate, the conversion of continental margin of east Asia from Andean type to west Pacific type, and the shift of TanchengLujiang fault belt from leftlateral strikeslip to rightlateral strikeslip.