东濮凹陷古近系烃源岩特征及其形成环境分析

Characteristics and formation environment analysis of Paleogene source rocks in Dongpu Depression

刘宣威,王学军,李红磊,张云献,张文彬,黄正

成都理工大学地球科学学院，四川 成都 610059 中国石化中原油田分公司勘探开发研究院，河南 濮阳 457001 中国石化华东石油工程有限公司江苏钻井公司，江苏 扬州 224261

School of Earth Sciences, Chengdu University of Technology, Chengdu 610059, China Exploration and Development Research Institute, Zhongyuan Oilfield Company, SINOPEC, Puyang 457001, China Technology Research Institute of Jiangsu Drilling Company, SINOPEC East China Petroleum Engineering Co., Ltd., Yangzhou 224261, China

为明确东濮凹陷古近系烃源岩特征及其成因环境，针对东濮凹陷多种环境频繁变化的特点，采用有机和无机相结合的方法，探讨了烃源岩的发育特征、地球化学特征及其成因。结果显示：东濮凹陷烃源岩具有自盐湖中心向外有机质丰度逐渐降低、有机质类型变差的特征。北部优质烃源岩较为发育，呈环盐岩带状分布；南部地区烃源岩有机质丰度低、类型差，优质烃源岩较少。北部地区烃源岩一般具有（C26+TT）/C30H＞0.4、γ蜡烷/C30H大于0.5、4￣甲基甾烷/C29大于0.4、C27＞C29（生标参数比值均为其质量比）的特征，自含盐区向无盐区，C26+TT和C27优势逐渐减弱；南部地区γ蜡烷、C26+TT和4￣甲基甾烷质量分数均较低，C29优势明显。东濮凹陷古近系间歇发育温湿气候，中—高盐度、强还原的水体环境有利于优质烃源岩的发育，是东濮凹陷优质烃源岩发育的主要原因。

In order to clarify the characteristics of Paleogene source rocks in Dongpu Depression and its genetic environment, in view of the frequent changes of various environments in Dongpu Depression, a combination of organic and inorganic methods was used to discuss the development characteristics of source rocks, geochemical characteristics and causes. The results show that the source rocks in the Dongpu Sag have the characteristics of gradual decrease in organic matter abundance and deterioration of organic matter types from the center of the salt lake. The high-quality source rocks in the north are relatively developed, and the salt rocks are distributed in a ring shape. The abundance of organic matter of the source rocks in the south is low, the type is poor, and high-quality source rocks are relatively poor; the source rocks in the north generally have the characteristics of （C26+TT）/C30H>0.4, G（gammacerane）/C30H>0.5, 4-methyl sterane/C29 regular sterane>0.4, C27>C29; from the salt-containing area to the salt-free area, the advantages of C26+TT and C27 regular sterane gradually weaken, and the content of gammacerane, C26+TT and 4-methyl sterane in the southern region are low, and regular steranes are dominant in C29; Dongpu Sag developed intermittently warm and humid climate during the Paleogene. During this period, the medium-high salinity and strong reducing water environment is conducive to the development of high-quality source rocks. It is the main reason for the development of high-quality source rocks in Dongpu Sag.

10.6056/dkyqt202104004