辽西凹陷Z区东营组层序地层格架

Study of Sequence Stratigraphy Framework of Dongying Formation in Area Z of Liaoxi Depression

袁竞 辛仁臣 宋修艳

YUAN Jing XIN Renchen SONG Xiuyan

中国石油化工股份有限公司上海海洋油气分公司研究院, 上海 200120; 中国地质大学(北京)海洋学院, 北京 100083

Institute of SINOPEC Shanghai Offshore Oil & Gas Company, Shanghai 200120, China; School of Marine Sciences of China University of Geosciences (Beijing), Beijing 100083, China

辽西凹陷Z区位于辽东湾海域西南部,已在古近系发现了绥中36-1亿吨级油田,展示了辽西南洼为富烃洼陷,具有巨大的油气勘探潜力。以古近系东营组为目标层系,综合分析全区的古生物、岩心、录井、测井及地震资料,将Z区东营组划分为3个三级层序,自下而上分别为SQd3、SQd2和SQd1,其中SQd3、SQd2均可进一步划分出湖扩域和高位域不同的层序界面在古生物、岩性、测井响应、地震反射特征上存在一定差异。构造-古地貌对层序具有明显的控制作用。在斜坡高部位和凸起区,东营组超覆于基岩之上,上覆馆陶组与东营组之间有明显的削截现象。东营组各三级层序内部,总体上表现出从水进到水退的沉积旋回,且具有不同的岩性、测井响应及地震反射特征。

Liaoxi depression is located in the southwest of Liaodong Bay, with Suizhong 36-1 oil field discovered in Paleogene of the southern Liaoxi depression (SLXD), which has hundred million tons of original oil in place (OOIP), indicating a great hydrocarbon potential in this area. Dongying Formation (Paleogene) is the main exploration targets in area Z of the southern Liaoxi depression. On the basis of the paleontological data, core, logging and seismic data, three sequences have been distinguished in Dongying Forma-tion from bottom to top, including SQd3, SQd2 and SQd1, of which SQd3 & SQd2 can be divided further into lacustrine-expanded systems tract and highstand system tract. Various sequence interfaces are different in the characteristics of paleontology, lithology, log responses and seismic reflection. The stratigraphic sequences and sedimentary systems are controlled obviously by the structures and paleogeomorphy. At the upland of slope and the uplifted area, Dongying Formation overlays on the basement rock, and trunca-tion occurred between Dongying Formation and the overlying Guantao Formation. Within order III sequence of Dongying formation, transgressive to regressive sedimentary cycles deposited, with obvious different lithology, log responses and seismic reflection char-acteristics.

https://doi.org/10.3969/j.issn.1008-2336.2013.01.038